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Sudari brodova rijetki su događaji, ali takvi koji mogu imati katastrofalne posljedice: gubitak ljudskih života, oštećenje brodske konstrukcije i onečišćenje okoliša. Zbog toga, tijekom konstruiranja brodske konstrukcije veoma je bitno obratiti pažnju na odziv konstrukcije uslijed takvog događaja. Zbog praktičnih razloga kao što su cijena i vrijeme, eksperimentalna istraživanja su rijetka te se umjesto njih provode numerička istraživanja. Također, kao dobar izvor podataka za konstruiranje novog broda s obzirom na odziv tijekom sudara, na raspolaganju stoje podatci o nesrećama koje su se već dogodile. Na početku ovog rada bit će spomenute neke od njih kako bi se stvorila općenita slika problematike. Cilj ovog rada je prikazati proces detaljnog modeliranja pramca broda za prijevoz sirove nafte, izrada adekvatne mreže konačnih elemenata te priprema nekoliko scenarija sudara takvog pramca s krutim zidom. Proračun sudara bit će proveden korištenjem nelinearne metode konačnih elemenata s naglaskom na analizu unutarnje mehanike sudara i strukturnu analizu konstrukcije. Priprema scenarija sudara uključuje prikaz postavljanja parametara proračuna kojima se pokušava što vjernije opisati stvarni događaj. Na kraju će biti analizirani i prikazani najbitniji podatci dobiveni proračunom. Proračun je proveden uz pomoć programskog paketa „LS-DYNA“. Ship collisions are rare events, but they can have catastrophic consequences: loss of human lives, damage to the ship's structure, and environmental pollution. Therefore, during the design of a ship's structure, it is crucial to pay attention to its response in such an event. Due to practical reasons such as cost and time, experimental research is scarce, and numerical investigations are conducted instead. Additionally, dana from accidents that have already occurred serve as valuable sources of data for designing a new ship, specifically regarding the structural response during a collision. Some of these accidents will be mentioned at the beginning of this paper to provide a general overview of the issue. The aim of this paper is to present the process of detailed modeling of the bow of a crude oil carrier ship, the creation of an appropriate finite element mesh, and the preparation of several collision scenarios involving striking bow and rigid wall. The calculation of collision will be performed using a nonlinear finite element method, focusing on the analysis of internal collision mechanics and structural analysis of the construction. The preparation of collision scenarios includes defining calculation parameters that aim to accurately describe the real event. Finally, the most important data obtained from the calculation will be analyzed and presented. The calculation was carried out using the software package "LS-DYNA."

The current work studied the crashworthiness behavior of thin-walled circular steel tubes against axial and oblique crushing. Parametric analyses of crushing angle and tube wall thickness were conducted aiming to identify their effect on dissipated energy, collapse initiation and deformation stability. Quasi-static experiments and finite element (FE) simulations in LS-DYNA were implemented for crushing angle parametric analysis, while the wall thickness effect was studied numerically for the same loading angle range. Both experiments and simulations revealed that an increase in crushing angle results in lower energy absorption (EA) and peak force. Low-angled oblique loading was indicated as the most efficient impact condition reaching sufficient EA and facilitating plastic collapse initiation. The occurrence of global bending mode revealed a critical loading angle value reacting to a significant EA drop due to unstable plastic deformation. Finally, higher wall thickness resulted in greater peak force and increased critical angle reacting to a smoother EA decrease with respect to loading angle by preventing unstable deformation mode.

A monopost seat is a novel, lightweight seat developed to utilize most of the interior space of vehicles. The space under the seat can be utilized by inserting a monopost columnar structure between a monopost seat rail and the floorboard. This design increases the perceived spaciousness of the vehicle and imparts passengers with a higher degree of freedom, because the seats can be adjusted more easily than standard seats. Meeting these requirements will require the seats to be sufficiently strong and sturdy in order to maintain passenger safety. Compared to traditional seats, it is more likely that a monopost seat will shift under the mass of the passenger, and these seats are more vulnerable to external vehicle collisions. Passenger safety is further compromised if an operational function is added. Therefore, further research on monopost seats is required. This study performed quasi-static and dynamic simulations to determine if the attachment of monopost seats to a vehicle meets international safety requirements in collision events. With a focus on clarifying the dynamic simulation process, the outcomes of quasi-static simulations were compared with the results obtained from dynamic simulations.

Ultra-high performance fiber-reinforced concrete (UHPFRC) is an advanced cement-based composite with enhanced compressive strength, tensile resistance and toughness when compared to conventional concrete. Interest in the application of UHPFRC as a retrofit material has been rapidly increasing, and a few existing studies have examined the ability of UHPFRC to retrofit and strengthen existing reinforced concrete (RC) structures under static loading; however, very limited studies have examined the effectiveness of UHPFRC to improve the response of RC members under blast loading. This thesis aims at filing this research gap and investigates the behavior of UHPFRC retrofitted RC flexural members under both static and blast loads. A total of twenty-one (21) specimens, in two different series are tested. Series 1 includes nine (9) singly-reinforced beams built with high-strength concrete (HSC) and strengthened by UHPFRC to improve shear and flexural behaviour. Series 2 includes a further twelve (12) doubly-reinforced beams/columns built with normal-strength concrete (NSC), and strengthened by UHPFRC to improve response under blast, or combined blast-axial loading. Various test parameters are examined including the effects of varying retrofit types (full jacket, U-jacket or T-sided), surface roughening methods, longitudinal steel reinforcement ratio, single vs. repeated blasts, and the effects of axial loading. The results from this thesis are presented in six journal articles. Papers 1 and 2 study the effects of UHPFRC jacketing on the static and blast behaviour of the singly-reinforced HSC beams in Series 1, while Paper 3 discusses the effects of additional parameters such as: the effect of retrofit type, roughening method and steel detailing on blast behaviour. Under static loading (Paper 1), the UHPFRC jacketing was found to be effective in increasing shear resistance (by preventing shear failure), and improving flexural behaviour (by increasing strength, stiffness, ductility and overall toughness) when compared to control beams built without UHPFRC. Similarly, under blast loads (Paper 2) the use of UHPFRC jacketing prevented shear failure, and improved flexural behaviour by reducing displacements at equivalent blasts, increasing overall blast capacity, and improving damage tolerance. On the other hand, the results show that UHPFRC-retrofitted beams with low longitudinal steel ratios may be vulnerable to brittle bar fracture failures. As part of the numerical research, finite element (FE) modelling is used to predict the static and blast behaviour of the test beams using software LS-DYNA (Papers 1 and 2). The results from Paper 3, provide further insights into the effects of retrofit type (FJ, UJ and T) and roughening method on blast performance; both the UJ and FJ retrofits were found to be effective in increasing shear resistance, reducing blast-displacements and increasing blast capacity, while the benefit of the T-sided retrofit was limited by the crushing capacity of HSC concrete. The effect of roughening method was found to be negligible, except at the very late stages of blast loading. Papers 4, 5 and 6 present the experimental results from the doubly-reinforced NSC beams tested in Series 2, with a focus on the effect of UHPFRC jacketing, UHPFRC retrofitting type and Axial loading, respectively. Paper 4 shows that the UHPFRC jacketing increased the stiffness and strength of the beams under both static and blast loading, however the high bond capacity of the UHPFRC and relatively low tension steel ratio increased the vulnerability of bar rupture failure. The numerical parametric study investigates the effects of steel ratio and blast load scenario, jacket thickness and interface location on blast performance and failure model. Paper 5 confirms that the blast performance of the beams is influenced by the retrofit type, with optimal performance obtained when using full- or U-jacketing. The efficient use of localized "hinge" retrofits was also found to be effective, and reduced the vulnerability to bar rupture. The numerical parametric study investigates the effects of steel ratio and blast load scenario (single vs. repeated) on the blast performance of the beams. Paper 6, studies the effect of UHPFRC jacketing in columns tested under combined axial and blast loading. The retrofit is shown to increase blast capacity and reduce blast-induced displacements and damage, though the final failure of the columns was governed by bar rupture. As part of the numerical parametric study the effects of axial load ratio, boundary conditions, steel ratio, jacket thickness and jacket design are studied numerically and found to have significant effects on blast behaviour and failure mode.

Fused deposition modeling (FDM) is one of the most common 3D printing technologies and is becoming a well-established production method. Short fiber-reinforced polymers represent a new class of printing materials that enhance the mechanical properties of final components, thus informing an interesting subject of analysis for this study. FDM-printed parts are characterized by a strong anisotropy, so their behavior should be analyzed accordingly. The authors proposed a modeling strategy based on a transversely isotropic behavior hypothesis, representing material behaviors associated with an elasticity matrix in relation to the elastic field and a combination of Hill’s yield criterion and Voce’s isotropic hardening law for the plastic field. Material properties of materials were experimentally identified through tensile tests on dog bone specimens printed with different orientations in space. The numerical model was then calibrated using the finite element software LS-DYNA and the optimization software LS-OPT. An agreement between numerical and experimental results showed the robustness of the modeling strategy proposed to describe the stress behaviors of printed materials until a maximum load is reached, while strain behaviors have yet to be correctly defined due to the difficulties associated with evaluating an equivalent deformation.

Numerical simulations have the potential to be used for designing damage-tolerance composite structures. However, numerical models are currently computationally intensive, and their post-failure evolution and fracture morphology predictions are still limited. In the present work, a numerical methodology to simulate advanced composite joints is presented. The results of a numerical campaign aimed to evaluate the progressive damage and failure analysis (PDFA) of an advanced pin-hole connection under tensile and compressive load are evaluated. A high-fidelity stacked shell-cohesive methodology is employed to simulate the ultimate load, fracture initiation, and propagation of the proposed composite joint. Post-failure erosion methodology is proposed to control the initiation and evolution of composite fractures. The location and extension of the numerically predicted damages are compared with experimental observations. The proposed methodology demonstrates its preliminary ability to be used for designing composite joints up to failure. Specific outcomes are also pointed out.

The shock sensitivity and ignition behavior of explosives and propellants are important safety characteristics for developing insensitive munitions (IM) and ignition systems. Material properties related to shock sensitivity are usually examined in initiation experiments such as flyer impact or gap tests resulting in critical velocities or gap lengths. With advanced methods, models for describing and simulating the initiation behavior of explosives are derived from these experiments but the universality of these models, e.g. I&G and HVRB, is questionable. Generally, these must be tuned for each experiment and depend on the experimental results, from which they are generated. Pop-plots from extensive experiments are usually the basis for optimizing these ignition models used in hydro codes. In this work different initiation models are evaluated for the applicability to predict the results of flyer impact experiments, using different hydro codes. Therefore, initiation models and parameters for HNS available in literature are used in flyer impact simulations and the results are compared and assessed based on the critical flyer velocity with respect to initiation. For deriving future initiation models an experimental setup for the generation of Pop-plots is introduced which could reduce the experimental effort in the future. This setup utilizes the miniaturized velocity of detonation measurement method, formally developed at Fraunhofer ICT.

Systems that allow engineering studies to be done in a virtual environment with computer software, to test designs in a virtual environment and to carry out design verification studies are developing day by day. The Finite Element Method (FEM) is a method used to simulate structurally with strength visualizations, production and weight determination, proper management of materials and costs, and numerically predict how a part or assembly behaves under certain conditions with Finite Element Analysis (FEA). In this paper, control of connection elements, material and mesh (solid, surface and volume) controls and preliminary analysis processes were carried out after transferring a 3D data with defined material and connection elements to Ls-DYNA program to perform Finite Element Analysis. As a result of the preliminary analysis, the crash test of the car with the wall was carried out with the Ls-DYNA program of the model, which is suitable for Finite Element analysis. The results of the crash test were interpreted in the Ls-DYNA program. In this study, it is aimed to understand the results according to time, car displacement and speed as a result of the collusion of the car with the wall.

At the objects of space infrastructure and at nuclear power facilities there are industrial structures, the main task of which is to protect a person, equipment or machinery from emergencies such as, for example, explosions, falling of various objects, fragments. In accordance with the requirements of the Federal Law On the Protection of the Population and Territories from Natural and Technogenic Emergencies, when calculating such structures, all types of loads corresponding to their functional purpose must be taken into account. So, for structures located in the area of a possible accident and the fall of space rockets, it is necessary to calculate for the fall of the destroyed parts of the rocket engine. For nuclear power plant facilities, such accidents occur when containers and other heavy objects fall on the ground, affecting underground structures located in the ground, and for civil defense protective structures built into the basement floors of buildings, it is necessary to consider situations in which the overlying floors of a building collapse when exposed to there is an air shock wave on them. Therefore, this problem is relevant, and in this study, a finite-element method for calculating an underground structure in a non-linear dynamic setting has been developed when a large overall object collides with the ground.

Incorporating elastomers such as polymers in protective structures to withstand high energetic dynamic loads, has gained significant interest. The main objective of this study is to investigate the influence of a Polyurea coating towards the blast-induced response in steel plates. As such, Polyurea coated steel plates were tested under near-field blast loads, produced by the detonation of 1 kg of spherical nitromethane charges, at a standoff distance of 150 mm. Mild steel (XLERPLATE 350) and high-strength steel (BIS80) plates with thicknesses of 10 mm were Polyurea coated with thicknesses of 6 mm and 12 mm on either the front (facing the charge) or the back face. The deformation profiles were measured using 3D scanning. Numerical simulations were performed using the non-linear finite element code LS-DYNA. The strain-dependent behaviour of the steel and Polyurea were represented by Johnson-cook and Money-Rivlin constitutive models, respectively. The numerical models were validated by comparing the plate deflection results obtained from the experiments and were then used in the subsequent parametric study to investigate the optimum thickness of the Polyurea coating. The results indicate that back face coating contributes towards an approximately 20% reduction in the residual deformation as well as the absence of melting of the Polyurea layer, while the front-face coating can be used a means of providing additional standoff distance to the steel plates.

Zugleich: Dissertation, Universität Kassel, 2022

A ligação adesiva vem ganhando protagonismo nos processos de ligação de materiais estruturais, incluindo a união de materiais dissimilares. Com a evolução tecnológica a ligação adesiva vem substituindo os métodos tradicionais como a soldadura, brasagem, e ligações mecânicas como aparafusamentos e rebitagens. Esta tendência deve-se a diversas vantagens que a ligação adesiva oferece, dos quais se destacam a obtenção de estruturas leves, com bom comportamento à fadiga, e sem esquecer que estas permitem ligações de materiais dissimilares e com menores concentrações de tensões quando comparado com os outros métodos de ligação. A crescente utilização da ligação adesiva torna vantajosa a existência de ferramentas que auxiliem o seu projeto. O Método de Elementos Finitos, combinado com critérios ou modelos de dano, tem-se revelado eficaz na simulação e previsão do comportamento de juntas adesivas, possibilitando assim a redução do tempo de projeto e dos custos. Entre os critérios ou modelos de dano associados ao Método de Elementos Finitos, os modelos de dano coesivo revelam bastante eficácia, combinando parâmetros de resistência e tenacidade para prever o desempenho de juntas adesivas. Com o objetivo de obter a melhor configuração de junta adesiva quando os aderentes são materiais dissimilares, especificamente Polímeros Reforçados com Fibra de Carbono (PRFC) e liga de alumínio, quando sujeita a temperaturas criogénicas e carga monotónica de tração uniaxial, na presente dissertação foi modelada em LS-Dyna uma junta adesiva tubular, tendo sido simuladas e analisadas cinco configurações com o mesmo compri- mento colado e lei coesiva do adesivo. A análise da resposta decorrente da simulação dos fenómenos físicos presentes no complexo processo de descolagem da junta foi realizada quantificando os valores de deslizamento interfacial e as tensões de aderência do adesivo e as extensões desenvolvidas nos aderentes ao longo do comprimento colado. Adhesive bonding has been gaining prominence in the bonding processes of structural materials, including the union of dissimilar materials. With technological evolution, ad- hesive bonding has replaced traditional methods such as bolting, brazing, and mechanical connections such as screwing and riveting. This trend is due to several advantages that the adhesive bond offers, of which the obtaining of light structures, with good fatigue behavior, and without forgetting that these allow connections of dissimilar materials and with lower concentrations of tensions when compared to the other connection methods. The growing use of adhesive bonding makes it beneficial to have tools to help the project. The Finite Element Method, combined with damage criteria or models, has proved to be effective in simulating and predicting the behavior of adhesive joints, thus enabling the reduction of design time and costs. Among the criteria or damage models as- sociated with the Finite Element Method, the cohesive damage models are quite effective, combining strength and toughness parameters to predict the performance of adhesive joints. With the aim of obtaining the best adhesive joint configuration when adherents are dis- similar materials, specifically Carbon Fiber Reinforced Polymers (CFRP) and aluminum alloy, when subjected to cryogenic temperatures and monotonic uniaxia tensile load, in the present dissertation a tubular adhesive joint was modeled in LS-Dyna, having been simulated and analyzed five configurations with the same length and cohesive law. The analysis of the response resulting from the simulation of the physical phenomena present in the complex process of debonding was carried out by depicting the interfacial slip and the adhesion stresses of the adhesive, and the extensions developed in the adherents along the length.

O livro de atas da 4.ª Conferência Científica é constituído por 35 artigos, onde divulga os mais recentes desenvolvimentos científicos e tecnológicos ao nível das Forças Armadas e da GNR, promovendo a colaboração dos investigadores dos diferentes Centros de Investigação militares (CIDIUM, CINAV, CINAMIL e CIAFA). Os artigos englobam diversas áreas das ciências militares: Estudo das Crises e dos Conflitos Armados (ECCA), Operações Militares (OM), Comportamento Humano e Saúde em Contexto Militar (CHSCM), e Técnicas e Tecnologias Militares (TTM). N/A

A estudo do Aqueduto dos Pegões apresenta um desafio devido à pouca informação disponível para a caracterização da sua alvenaria de pedra. Devido à vulnerabilidade da alvenaria de pedra a cargas explosivas, o estudo destas estruturas é relevante para a segurança das mesmas. A longa extensão do aqueduto dos Pegões dificulta a sua análise através de modelos pormenorizados. De modo a analisar a influência da extensão em planta em relação a um pilar, foram realizados vários modelos para determinar a extensão longitudinal necessária para caracterizar a resposta estrutural em caso de explosão no programa LS-Dyna com recurso a elementos finitos. Para a caracterização da alvenaria foram utilizados parâmetros de um artigo no qual foram ensaiadas várias amostras à compressão vertical. Foi criado um modelo em LS-Dyna de uma parede de pedra do artigo e este modelo foi calibrado para aproximar a curva força-deslocamento dos modelos numéricos aos experimentais. Estes valores calibrados foram de seguida utilizados para os modelos do troço do aqueduto para proceder à simulação em situação de carga explosiva de 50, 150 e 500 kg de TNT equivalente a várias distâncias de detonação. Os resultados permitem estabelecer valores mínimos das extensões longitudinais em planta para serem utilizados em estudos futuros. The study of the Pegões aqueduct presents a challenge due to the lack of information for the characterization of the stone masonry. Due to the vulnerability of stone masonry to explosive loads, the behavior of these structures is a relevant study for the safety of these structures. The long extension of the Pegões aqueduct makes its analysis difficult through detailed models. In order to analyze the influence of the extension in plan in relation to col-umn 11, several models were performed to determine the longitudinal extension necessary to characterize the structural response in the event of an explosion in the LS-Dyna program us-ing finite element analysis. In order to characterize the stone masonry parameters an article from which several samples under vertical compression were tested was used. An LS-Dyna model of a stone wall of the article was created and this model was calibrated to approximate the force-displace-ment curve of the numerical and experimental models. These calibrated values were then used for the models of the aqueduct section to carry out the simulation in a situation of explo-sive loading of 50, 150 and 500 kg from varied distances. The results allow establishing a lower limit for the extension in plan to be used in future studies.

High-strength steel (HSS) conforming to ASTM A1035 is becoming increasingly used in various structural applications, including in high-rise buildings and bridges. Due to their chemistry and manufacturing process, ASTM A1035 steel bars result in a combination of high tensile strength to yield ratio and varying levels of corrosion resistance. One potential application of ASTM A1035 bars is in the blast-resistant design of concrete structures, where their use can allow for reduced steel congestion, and increased blast resistance. Despite their high initial cost, stainless steel (SS) reinforcing bars are also seeing increased use in concrete construction. Solid stainless steel bars are referenced in ASTM A955, which is applicable to various stainless steel alloys. In addition to their inherent corrosion resistance, most stainless steel bars possess greater tensile strength, and importantly, exceptional ductility, when compared to ordinary steel reinforcement. This unique combination of strength and ductility makes SS bars well-suited for blast design applications. The overarching aim of this thesis is to gain better understanding of the blast behavior of RC flexural members designed with high-strength (HSS) and stainless steel (SS) reinforcement. This objective is achieved through a combined experimental and numerical research program. As part of the experimental research, a large set of beams, subdivided into three series, are tested under either quasi-static bending or simulated blast loads using the University of Ottawa shock-tube. Series 1 (HSC-HSS) and Series 2 (HSC-SS) aim at examining the effects of blast detailing (as recommended in modern blast codes,) on the quasi-static, blast and post-blast behaviour of high-strength concrete (HSC) beams reinforced with either ASTM A1035 high-strength bars (8 beams) or ASTM A955 stainless steel bars (16 beams). In addition to the influence of detailing, the effects of steel grade/type, steel ratio and steel fibers are also studied. Series 3 further studies the benefits of combining higher grade or higher ductility reinforcement, with more advanced ultra-high performance concrete (UHPC). This series includes 20 UHPC beams built with either ordinary, HSS or SS reinforcing bars (UHPC-NSS, UHPC-HSS and UHPC-SS). In addition to the effect of steel grade/type, concrete type, steel ratio and steel detailing are also studied. The results from Series 1 and 2 demonstrate the benefits of implementing high-strength and stainless steel reinforcement in HSC beams subjected to blast loads, where their use leads to increased blast capacity, reduced support rotations, and higher damage tolerance. The results further demonstrate the benefits of “blast detailing” on the ductility and resilience of such beams, under both static and blast loads. The results also show that the use of steel fibers can be used to relax blast detailing in the beams with high-strength or stainless steel by increasing the required tie spacing from d/4 to d/2. The results from Series 3 confirm that the use of UHPC in beams enhances flexural response (in terms of strength and stiffness), which in turn results in superior blast resistance. Conversely, the high bond capacity of UHPC makes such beams more vulnerable to bar fracture. Increasing the steel ratio is found to effectively increase the failure displacement and ductility of the UHPC beams. The use of high-strength steel is found to increase load capacity and blast resistance, while the use of stainless steel results in remarkable ductility, which further enhances beam response under blast loading. As part of the numerical research program, the static and blast responses of the test beams are simulated using either 2D or 3D finite element (FE) modelling, using software VecTor2 and LS-DYNA. The numerical results show that the 2D FE modelling using software VecTor2 can provide reliable predictions of the static and blast responses of the HSS or SS reinforced HSC beams built with varying detailing, in terms of load-deflection response, cracking patterns, failure mode, displacement time histories and dynamic reactions. Likewise, the 3D FE modelling using software LS-DYNA with appropriate modelling of UHPC (using the Winfrith Concrete or CSCM models) can well predict the blast responses of UHPC beams with ordinary, high-strength and stainless steel, in terms of displacement/load-time histories, damage and failure modes.

Studied and described the basics of computer modeling technique for truck cab testing in compliance with the international UNECE safety regulation No 29. Analyzed the features of the tests in accordance with Revision 2, 03 series of amendments to the Regulation. Shown an example of truck cab computer test simulation with use of ANSYS LS-DYNA software. Model properties settings and simulation results analysis concerned with estimation of the residual space in the cabin is made using LS-PrePost.

The fascia of a car is a part that is responsible for absorbing the impact during a frontal or rear collision involving vehicles. Energy absorption is a critical parameter in determining the fascia’s efficiency. Twill weave Kenaf and Plain weave Kevlar polymer composites were used to study low-velocity impact behavior. CATIA V5 R20 software was used to create a 3-D solid model of fascia, which was then imported into the Hypermesh environment and simulated using LS-DYNA. In Economic Commission for Europe (ECE) United Nations Agreement, regulations were used to simulate the process for the study. Under the maximum deflection, the intensity was investigated in elastic mode using energy absorption and impact behaviour. The collision test was conducted at a constant low velocity of 4 km/hr., for five different laminate sequences L1 to L5, with fabric stacking as the predominant parameter. Further, L3, L4 and L5 hybrid laminates were compared with pure Kevlar (L1) and Kenaf (L2) laminates. The results were interpreted by using LS-PREPOST to analyze the energy absorption characteristics during crash for different materials. It was observed that the maximum internal energy uptake was recorded by L5 based on the stress distribution model. When compared to L3 and L4, L5 accounted for a 48 percent and a 24 percent increase in energy absorption, respectively, which clearly indicates that hybridization, stacking pattern adopted and the orientation of fabric have greatly influenced the strength of the laminate. In addition to these, the automobile industry can benefit from the use of renewable and environment-friendly materials considered for this study.

Explosions caused by standoff charges near buildings have drastic effects on the internal and external structural elements which can cause loss of life and fatal injuries in case of failure or collapse of the structural element. Providing structural elements with blast resistance is therefore gaining increasing importance. This paper presents numerical investigation of RC columns with different reinforcement detailing subjected to near-field explosions. Detailed finite element models are made using LS-DYNA software package for several columns having seismic and conventional reinforcement detailing which were previously tested under blast loads. The numerical results show agreement with the published experimental results regarding displacements and damage pattern. Seismic detailing of columns enhances the failure shape of the column and decrease the displacement values compared to columns with conventional reinforcement detailing. Further, the effect of several modeling parameters are studied such as mesh sensitivity analysis, inclusion of air medium and erosion values on the displacements and damage pattern. The results show that decreasing the mesh size, increasing erosion value and inclusion of air region provide results that are very close to experimental results. Additionally, application is made on a slab-column multistory building provided with protective walls having different connection details subjected to blast loads. The results of this study are presented and discussed. Use of a top and bottom floor slab connection of protective RC walls are better than using the full connection at the four sides to the adjacent columns and slabs. This leads to minimizing the distortion and failure of column, and therefore it increases the chance of saving the building from collapse and saving human lives. Doi: 10.28991/cej-2021-03091733 Full Text: PDF

Investigation and analysis of the dynamic behavior of composite materials and their failure resistance are essential. The main aim of this study is to investigate the improvement of impact properties of incorporated glass fiber reinforced polymer (GFRP) composite specimens with various loading of nanoclay and nanosilica in a corrosive environment. After fabrication of samples by hand layup method, all of them were immersed in 5 wt. % of sulfuric acid solution for 0, 1 and 3 months. As the immersion time increased, the specimens containing nanosilica absorbed more water than the other samples. The force-displacement, force-time and energy-time diagrams showed the superiority of filled composites with nanoparticles over the pure sample in all immersion periods. Low-velocity impact (LVI) test results of specimens containing nanoclay showed a better behavior and with the addition of 5 wt. % of nanoclay, the impact force increased by 15.72% and the displacement decreased by 5.26%. Also, in these samples, the energy absorption rate decreased by 17.15%, which was associated with a reduction in the damage rate. After immersion of specimens in different times, specimens containing 5 wt. % of nanoclay had better strength than other samples and maintained their superior properties. The obtained results illustrated that the addition of 1 and 3 wt. % of nanosilica had no specific effect on the improvement of impact properties. Finally, incorporated GPRP composites with 3 wt. % of nanoparticles were simulated using LS-DYNA software and the experimental and numerical results were compared to investigate their accordance.

Bu çalışmada, otomotiv sektöründe kullanılan boru profillerin boru bükme makinelerinde döner çekme yöntemi ile farklı çap ve et kalınlıklarında çelik malzemelerden boruların bükümü esnasında büküm parametlerinin geri esnemeye etkileri incelenmektedir. Boru bükme prosesi, uzay-havacılık ve otomotiv sektörlerinde oldukça kompleks şase kısımlarının tek parçada üretilebilmesini sağlayarak komponentin ağırlığını ve üretim maliyetini düşürmesi nedeniyle tercih edilmektedir. Boru bükme prosesinde Döner-Çekme (Rotary Draw), Makaralı-İtme (Push Rolling), Sıkıştırmayla (Compression) ve Pres Kütüğü (Ram) ile boru bükme yöntemleri kullanılır. Bükülen boruların kullanıldığı bu gibi yerlerde hassas büküm açısı ve uygun kesit alanı önem arz etmektedir. Boru bükme proseslerinde en sık karşılaşılan problem kesit alanı bozulmasıdır. Büküm açısını etkileyen bir diğer önemli faktör de geri esneme miktarıdır. Makaralı itme ile bükümde kalıp çapından çok daha büyük radyüslü büküm işlemleri yapıldığı için geri esneme bükülen borunun malzemesi ve kesitine bağlı olarak daha yüksek ölçeklerde görülebilmektedir. Açık ve kapalı kesit alanına sahip profillerin geri yaylanma davranışları kesit alanlarının şekline, kesit alanı ölçülerine, bükme yarıçapına ve bükme açısına göre değişkenlikler gösterir. Bu çalışmada ayrıca boru kesit alanındaki bozukluklar incelenmektedir. Çünkü bükülen borunun iç yüzeyinde (borunun kalıba değdiği yüzey) kalınlaşma görülürken, borunun dış yüzeyinde ise incelmelere rastlanmaktadır. Son olarak, boru bükmede karşılaşılan problemlerin oluşmaması için neler yapılması gerektiği açıklanmaktadır. In this research, an investigation of bending parameters of tubular profiles bent by tube bending machines during bending through Push Rolling method shall be conducted for those used in automotive industry. Tube bending process offers production of chassis parts with highly complicated geometries as single components so that it can reduce weight and manufacturing cost of the components hence it has been preferred in fields of aerespace and automotive. Precise degree of bending and proper cross-section area is of paramount importance in such fields where bent tubes are used. Cross-section distortion is the most widely confronted problem in tube bending process. In tube bending process, Rotary Draw, Push Rolling, Compression and Ram methods are utilized. Another significant factor affecting the degree of bending is the springback. Since bending radius is much larger in comparison to the die radius in the rotary draw bending, the springback occurs large scales depending on the cross-section and the material of the tube material. Springback behaviour of profiles with open and closed cross-section can be various depending on the dimensions and forms of the cross-section area, bending radii, and degree of bend. The distortions at the cross-section area of pipes are investigated. Because while thickening of the inner surface of a bending tube (the surface in vicinity of die) is observed, thinning on the extrados of the tube can be confronted. To sum up, what can be done to prevent such issues in tube bending shall be explained.

The aim of this study is the analysis of the multiple pelvis fracture mechanism in side-impact dynamic load cases. The elaborated numerical model of a pelvis complex includes pelvic and sacral bones as well as soft tissues such as ligaments and cartilages. The bone has been modelled as a viscoelasticity material based on the Johnson–Cook model. The model parameters have been chosen based on the experimental data. The uniqueness of a presented approach refers to the selection of crack criteria for the bone. Thus, it was allowed to analyse the process of multiple fractures inside the pelvic bones. The analysis was evaluated for the model in which the deformation rate influences the bone material properties. As a result, the stress distributions inside particular bones were changed. It has been estimated that the results can vary by 50% or even more depending on the type of boundary conditions adopted. The second step of work was a numerical analysis of military vehicle subjected to an IED. An analysis of the impactor’s impact on the pelvis of the Hybrid ES-2RE mannequin was conducted. It was shown that the force in the pelvis exceeds the critical value by a factor of 10. The results of the numerical analysis were then used to validate the model of a military vehicle with a soldier. It was shown that for the adopted loading conditions, the critical value of the force in the pelvis was not exceeded.

There is growing concern about the possibility of a suicide bomber being immolated when the army forces or the law enforcement agencies discover the place where they prepare their material or simply find themselves inside a building. To study the possible effects that these improvised explosive devices (IEDs) would have on the structures, eight tests were carried out with various configurations of IEDs with vest bombs inside a reinforced concrete (including walls and roof) building constructed ad hoc for these tests. These vests were made with different explosives (black powder, ANFO, AN/AL, PG2). For the characterization of these tests, a high-speed camera and pressure and acceleration sensors were used. The structure behaved surprisingly well, as it withstood all the first seven detonations without apparent structural damage. In the last detonation, located on the ground and with a significant explosive charge, the structural integrity of the roof and some of the walls was compromised. The simulation of the building was carried out with the LS-DYNA software with a Lagrangian formulation for the walls, using the LBE (based on CONWEP) module for the application of the charge. Despite the difficulty of this simulation, the results obtained, in terms of applied pressures and measured accelerations, are acceptable with differences of about 20%.

Zugleich: Dissertation, Universität Kassel, 2021. Doktorarbeit.

The paper presents the results of simulation tests of the entry of a floating transporter to a water obstacle. The simulation tests were performed with the use of LS Dyna program, based on the finite element method (FEM). The computational model was developed and used in the simulation of the manoeuvre of entering the water obstacle for the extreme conditions, which are described by NATO standards. For a model, as an example vehicle, the floating transporter PTS-M was used. The results of the application of the elaborated model confirmed the possibility to utilise the method to verify the behaviour of a vehicle in a very important and difficult problem from the point of view of vehicle safety conditions.

Pyrotechnic separation devices are widely used in space separation systems. However, these devices produce high-frequency, high-amplitude shock responses during operation, which endangers the safety of space systems. Hence, it is imperative to study the shock mechanism and characteristics during the unlocking process of a pyrotechnic separation device. This paper uses LS-DYNA finite element software and experiments to analyze the separation characteristics of the separation nut and predict its shock response, quantitatively decoupling the impact of preload and internal mechanism motion on separation shock. The results indicate that the shock response caused by the impact on the inner sleeve is the primary contributor to the total shock response of the separation nut (approximately 55% of the total response). The shock response caused by the release of the strain energy is very small, accounting for less than 5% of the total shock response. Adjusting the preload force without changing the charge and structure of the separation device did not have a clear impact on reducing the shock. This study shows that the shock of the separation device can be decreased by reducing the impact on the inner sleeve.

Single point incremental forming (SPIF) is a choice of interest in many manufacturing industries due to its wide range of applications. Materials such as copper, aluminum, steel, and many others formed various complex shapes through this process. However, the forming process could sometimes result in process defects, which could strongly influence the formed parts' geometric accuracy. The twist defect is one of them, which incrementally twists the forming sheet with a small angle at each forming step. In this paper, twist phenomena in the SPIF process have been investigated both numerically and experimentally. In the experiment, Aluminum Alloy (AA5052) was used to form a truncated pyramid shape, and a room temperature tensile test has been conducted to achieve the material's tensile properties. Then, the material property used in the simulation study of the SPIF using LS-DYNA software, where twist defect, stresses, strain, and thickness distribution are studied. The results from simulation and experiment show significant similarity against the expected results and this conveys that the proposed FE model of the SPIF process can be used to investigate the presence of twist, distributions of stress and strain, and thinning locations in the formed part.

The propagation of shock waves in confined environments is a complex phenomenon due to the potential for a multiplicity of reflections, diffraction and superposition of waves. The study of such wave propagation effects, which is different from the propagation of shock waves in free-field scenarios, is not entirely described in literature, especially when studying their influence on the response of structures. The analysis of such phenomena is of extreme relevance to the evaluation of protective structures to ensure the security of equipment and personnel. This paper studies the influence of shock wave related parameters on the mechanical response of simple structural elements. This is achieved through the analysis of the impulse train, multiple positive and negative pressure profiles and signal simplifications. This research uses the finite element code LS-DYNA to analyse the structural response sensitivity of a metallic plate to different parameters, when subjected to pressure data recorded from experimental tests. It is observed that the structural response is significantly influenced by the loading regime. Results indicate that the impulse has a significant effect on the deflection-time history of the structure in the impulsive regime and that the peak pressure and pulse duration affect the deflection response in the dynamic regime. It also shows that correctly defining the negative impulse train in the pressure-time history is one of the main factors leading to an accurate modelling of the mechanical response of the structure. It is also found that a complex and realistic pressure history profile can be reduced to a simplified pulse for structural analysis and design purposes.

According to the structure form of room and pillar goaf in gypsum mine, the mechanical model of pillar roof composite supporting structure was established in this research. Based on the cusp catastrophe theory and energy dissipation theory, the energy dissipation relationship of the support structure was analyzed, and a new instability criterion of the support system was derived by introducing the control parameters α and β. On this basis, the study of blasting caving was carried out. The influence of row spacing and hole depth on blasting caving was analyzed using ANSYS/LS DYNA software. The blasting influence range, stress wave attenuation and vibration velocity attenuation indices are obtained, and the blasting parameters such as the optimal distance and depth of blast holes between pillars and roof were optimized. Based on the results of theoretical analysis and numerical, combined with the engineering geological conditions of Dahan gypsum mine, the practical study of blasting caving was carried out. The caving scheme and caving sequence was determined, then the blasting caving effect was analyzed. The caving effect was found to be good, and the applicability of the theoretical model is verified.

This paper deals with the comparative analysis of the roll cage for the performance automobile. In a performance automobile, the roll cage is one of the main components. It forms the structure which provides additional protection and prevents the vehicle from crumbling. It must be of adequate strength to protect the driver in the event of a rollover or impact. There are different organizations across the globe which provides car manufacturer a certificate of crash worthiness and structural strength of the cars during the collision. Conducting the car crash test will take much time and cost so in order to solve these problems and Improvise the design of the Body in White part of the car (BIW) a finite element model of the car is developed and it is tested virtually over and over to ensure that the passengers are safe inside the car during an impact. The main thing about the simulation is the cost effectiveness and can be done in lesser amount of time than testing the actual model. Mainly there are three modes of crash testing which are performed in Insurance institute of Highway Safety such are Frontal Impact test, Side way Impact test and Roll over test. Here a BIW part of the car is taken along with the roll cage designed by us with carbon fiber (ePA-CF) material properties and ASTM A36 steel properties (comparison) for the dynamic analysis using ANSYS workbench and LS DYNA.

Considerable research has been carried out to establish a rational assessment method for nuclear power plants against external projectile impact. Most of the empirical formulas have been proposed to quantitatively investigate local damage to reinforced concrete (RC) structures caused by rigid projectile impact. These formulas were derived based on impact tests performed normal to the target structure, while only a few impact tests oblique to the target structure were studied. This work aims to propose a new formula for evaluating local damage to RC structures caused by oblique impact based on experimental and simulation results. At present, we have validated an analytical method via comparison with experimental results and have conducted simulation analyses of oblique impact assessments on RC slabs using projectile with flat nose shape. In this study, the same analytical method will be used to investigate perforation damage to RC slabs subjected to oblique impact by projectiles with hemispherical nose shape. The effect of projectile nose shape on perforation damage to RC slabs, the residual velocity of projectiles and the time history of energy transmission will be discussed.

The rock-breaking efficiency of a drilling tool directly affects the production costs and progress of foundation construction. It is essential to understand the mechanism of mechanical rock-breaking to improve rock-breaking efficiency. In this study, dynamic rock-breaking simulation research was carried out on a drill bit and was based on the LS-DYNA simulation platform. Additionally, the influence of the rotational speed of the spindle and the feed rate on the force of the drill bit in the rock-breaking process was obtained. The influence of the rotational speed of the spindle and the feed rate on drill vibration was also analyzed. The content of the presented theoretical and simulation research was verified through experiments. The following conclusions were drawn: first, the reaction force that rock has on the drill bit presents a law according to different rock types and drilling process parameters. With the increase in rotational speed, the axial reaction force decreases. With the increase in the feed rate, the axial reaction force increases. The effect of rock type on axial reaction force is nonlinear. Second, the influence of the spindle rotational speed and feed rate on the vibration of the drill bit also presents a law during rock-breaking. When the feed amount is constant, the transverse vibration slows down, and the axial vibration intensifies as the rotational speed increases. When the rotational speed is constant, as the feed increases, the transverse vibration slows down and the axial vibration intensifies. The research results provide a theoretical basis for selecting drilling process parameters and for improving rock-breaking efficiency.

The Continuous Surface Cap Model (CSCM) is one of the most widely used concrete models in LS-DYNA. The model is capable of capturing many important nonlinear mechanical behaviors of concrete well. The model has a built-in auto calibration procedure based on CEB-FIP code data. However, the built-in calibration procedure estimates material properties with significant errors, especially for tensile strength. Our study highlights the imperfection of the built-in automated material calibration procedure by the example of one-element uniaxial tension and compression tests. A calibration procedure is proposed, which significantly improves the accuracy of the material properties calculation: tensile and compressive strength and fracture energy. It is shown that the model with the proposed calibration procedure can describe the structure defamations and the fracture zone patterns more accurately.

Following a shaft failure or loss of load in a gas turbine engine, the turbine overspeeds due to the continuing expansion through the stage(s). The overspeed may result in hazardous conditions which have to be prevented. Several mitigation methods include the control system’s response by shutting the fuel flow, mechanical friction to reduce turbine acceleration, and blade release at a predetermined rotational speed. The release of the blades not only terminates the gas torque which accelerates the disk, but also increases the disk burst speed at reduced centrifugal load. In this manuscript, a design space exploration is presented to avoid disk burst by blade-off in a civil large turbofan engine through a parametric design of blade firtree and disk post system. The firtree design parameters used in the study are the contact angle between the blade firtree and the disk post, firtree bottom flank angle, firtree flank length and firtree thickness with respect to the disk post. The LS-DYNA finite element software was used in the simulations to generate possible failure scenarios. These were ‘disk burst’ and ‘blade-off’. Blade-off conditions manifested in two ways as a function of design parameters. The first type was blade release from serrations without disk post failure, and the second type was blade escape with disk post failure. Following the design space exploration, the effect of several design and material parameters on the design space was investigated. These parameters are; the contact friction coefficient between the blade firtree and disk post, firtree serration number, and the strain hardening behavior of the material.

Relevance. By its nature, seismic action is represented by the accelerogram a pronounced multidimensional random process, generally containing six components. The calculation in the deterministic formulation does not always allow to adequately assess the reaction of the system. While the calculation in the probabilistic formulation more adequately reflects the work of the system and makes it possible to evaluate its seismic resistance with a given security. The aim of the work is to assess the actual load-carrying capacity safety margin and the taken when designing coefficient K1, taking into account the permissible damage to buildings and structures for the steel spatial frame when calculating on the seismic action. Methods. In the article, the steel spatial frame was calculated for two sets of accelerograms, with dominant frequencies close to the main frequencies of the frame's natural vibrations. Each set was synthesized as a family of unsteady random seismic impact implementations. The calculation was carried out on two-component seismic action in nonlinear dynamic formulation in the software complex LS-DYNA. Previously, the frame was designed in accordance with national standard SP 14.13330.2014 “Construction in seismic areas on the seismic action” of the design earthquake level in the software complex PC LIRA 10.8. According to the developed probabilistic method for each set the actual load-carrying capacity safety margins were obtained and the coefficients K1 were estimated. Results . An analysis of the results shows that the steel frame under consideration has a sufficiently large margin of load-carrying capacity, and the coefficient K1 is taken in norms excessively conservatively. The developed technique allows to correct the value of the accepted coefficient K1 for buildings and structures of certain structural schemes. That in its turn will increase the economic efficiency of construction in seismic areas and ensure the reliability of the designed buildings and structures.

The protection of critical infrastructure, including government buildings, airports, religious buildings, military buildings and military vehicles, which are at risk to blast loads, has become important due to increasing terrorist activities in recent years. Sacrificial cladding systems based on negative Poisson’s ratio core topologies have recently received more attention as a protective technology due to its excellent energy absorption capability. In this study, field blast tests were performed on metallic re-entrant honeycomb-cored sacrificial cladding systems as protective structures for steel plate structures. This study focused on the near-field blast loading conditions where liquid Nitromethane (NM) spherical charges were detonated in close proximity to the main structure. Two 6 mm thick mild steel plates and two steel plates protected with re-entrant honeycomb-cored sacrificial cladding systems were among the specimens tested. The proposed auxetic cladding system was fabricated from aluminium sheets using a novel in-house built folding machine. Numerical simulations were conducted utilising LS-DYNA software and the Blast Impact Impulse Model (BIIM). The results obtained from the numerical simulations are in good agreement with the experimental results. It was found that the deformation pattern of the sacrificial auxetic cladding system varies with the intensity of the blast loading, and there is a limit at which the proposed protective system ceases to effectively absorb the applied blast loading. The variation of negative Poisson’s ratio of the system with blast loading was studied. It was found that the auxetic cladding system could become a solid projectile leading to damage amplification for very close-range blast loads due to rapid densification of the auxetic core. The proposed cladding systems with narrow re-entrant angles performed well under blast loads due to relatively low stiffness of the panels. Finally, the optimisation study was performed for the protective system. Overall, the experimental and numerical results assure that auxetic-based cladding systems are suitable for applications requiring blast protection such as armoured vehicles and critical physical infrastructure but need to be carefully designed for the given blast threat to prevent overloading of the protected structures.

Composite sandwich panels are commonly considered as lightweight materials for structural design in many applications including automotive, aerospace and defence systems. These panels must be devel...

The paper presents the analysis of birdstrikes using SPH bird impacts model, 4 lb and 8 lb, on a small bay of a leading edge of an aircraft. Theoretical and numerical investigations were dedicated ...

Composite materials are being widely used in automobile industry in order to meet the ever increasing demand to achieve significant weight reduction by maintaining the performance levels. Additiona...

The phase field method transfers the crack surface area into a domain integral through a smeared damage parameter. As a result, the fracture energy release rate can be directly incorporated into th...

Experimental and numerical studies on the effect of oblique impacts on the ballistic properties of GFRP were carried out. Ballistic tests of specimens using a steel sphere with a diameter of 6.35 mm were performed for inclination angles from the normal of 0, 15, 30, 45, and 60 degrees. Ballistic curves and ballistic limits for each case were obtained, and a function approximating these results was proposed. The size of the delamination area at different angles was also analyzed. The results showed that the most catastrophic failures cases of impact were impacts with angles of 0°–30°. Computational studies of impact loading during oblique impacts were carried out in LS-DYNA using the mesoscale yarn-level model (MSM). Finally, numerically obtained ballistic limits and damaged areas were compared with experimental ones.

One of the biggest challenges associated with modelling the behaviour of reinforced concrete is the difficulty of incorporating realistic material models that can represent the observable behaviour of the physical system. Experiments for relevant loading rates and pressures reveal that steel and concrete exhibits a complicated nonlinear behavior that is difficult to capture in a single constitutive model. LS-DYNA provides several material models to simulate the structural behaviour of reinforced concrete. To provide some guidance in selecting the proper one for users who have limited experience on numerical simulation of steel and concrete, this paper reviews the background theory and evaluates performance of different material models to predicting the response of reinforced concrete structures to dynamic loads as well as advantageous and disadvantageous of models. Comparisons of several widely available concrete constitutive models are presented pertaining to their ability to reproduce basic laboratory data for concrete and steel as well as predict the response of structures subjected to shock and impact loadings. The performance of these models was assessed by comparison of finite element analysis model and experimental results of reinforced concrete structures to insure that the overall behaviour prediction is qualitatively acceptable, even if the exact parameter fit or material characterization is not available. The authors concluded that the accuracy of the finite element results relied on the selection of material model as well as the input parameter values. The material model assessment presented in this study can be used in the numerical simulation to generate appropriate models for concrete and steel.

The methods and results of the modeling of explosions and the kinetics of the stress-strain state of high-voltage, oil-filled electrical equipment are presented on the example of the destruction of high-voltage, oil-filled transformers in the event of a short circuit. The theory, methods, and developed modules in the Flow Vision and Gas Dynamic Tool (GDT) packages and the pairing of the ANSYS and LS DYNA packages are described. The physical and mathematical models underlying the developed approaches, computational schemes, and packet interfaces are described. A comparison with the experimental results is made.

Composite sandwich structures under ballistic impact loading can be a key point in the design for defense applications. This paper presents new armor designs consist of two composite plates with honeycomb core subjected to ballistic impact via 0.3-caliber Armor-Piercing projectile APM2. The numerical modeling of composite materials poses high challenges in simulating their anisotropic behavior under impact loading. Optimizing the failure criteria and examining the influence of changing the materials on ballistic response and energy absorption are considered. An enhanced composite constitutive model for composite plates and Johnson–Cook constitutive model for metallic honeycomb core are employed to permit the simulation of dynamic plastic deformations with the failure mechanisms during impact loading in LS-DYNA. A three-dimensional simulation is employed as highly efficient through the back-analysis of laboratory tests. The results of the numerical simulations are found to be in good agreement with the experimental results. Numerical studies are performed to assess the effects of different composite materials and various aluminum alloys for honeycomb core with different impact velocities on the behavior of hybrid composite sandwich armor. The proposed armor design can introduce a significant influence on enhancing the new armors generations and achieving good sturdiness and lightweight armors for defense applications.

[Objectives] The purpose of this paper is to solve the main steam pipeline whipping protection problem from a ship's steam generator(SG) to the cabin wall.[Methods] Therefore, a finite element model of the inverted L-shaped pipeline and U-bolts is established using LS-DYNA software to simulate the collision dynamic process. Under two layout schemes,the stress-strain distribution and restraint rejection force time history curves of the U-bolts are analyzed.[Results] In collisions caused by the imaginary welding seam break of the SG oblique steam exit,the horizontal pipeline displacement is even greater than the vertical,requiring the installation of another group of U-bolts to restrain lateral pipeline movement. With regard to such limiting factors as cabin spatial dimensions and seam break collision protection for the right-angle elbow at both ends,one set of 45-degree obliquely installed U-bolts located at the inverted L-shaped pipeline elbow can replace two sets of horizontally and vertically installed U-bolts.[Conclusions] The results of this study can have guiding significance for the whipping protection design of the main nuclear power steam pipelines of ships.

This study aims to develop of the bird-impactor model for mathematical modeling of turbofan engine parts damage processes in case of a bird ingestion into the its air-gas channel. The bird-impactor model was justified for simulation of bird with mass of 0,70…3,65 kg for certification requirements on aircraft engines according to aviation regulations CS-E, FAR-33, AP-33. It was implemented in numerical SPH model for explicit LS-DYNA Solver of ANSYS LS-DYNA software package. The pre - and postprocessor LS-PrePost program also was used for numerical SPH model generating, preparing input data and processing the results from calculations. The bird-impactor model was had a hemispherical-ended cylinder geometry form. Material of the bird-impactor model was defined as a mixture of water (90-percent of volume) and air (10-percent of volume). The Null material model with low strength and the linear polynomial equation of state were used for the bird modeling. It was considered impacts bird to the rigid plate at striking velocities of 100...300 m/s and impact angle of 45°, 90° for the bird- impactor model verification. The rigid plate was modeled as a fixed thick steel plate. Volume of rigid plate was meshed with finite elements. The transducer was installed in center of the rigid plate. It was modeled by one finite element. The pressure of impact bird was obtained by dividing the contact force for finite element - transducer to its area. Thus the pressure curves were calculated for each impact bird to rigid plate. The Hugoniot pressure (shock pressure) was defined as maximum of pressure curve. The stagnation pressure was defined for phase of curve with approximately constant low pressure level by Simpson's rule. Verification of the developed bird-impactor model was performed by comparing the calculating results of Hugoniot and stagnation pressures used the developed bird-impactor, the one-dimensional hydrodynamic theory and calculation results of other authors. Verification of developed the bird-impactor model was shown good agreement with the one-dimensional hydrodynamic theory and with results of other authors.