Search

Fibre-reinforced composites (FRPs) are strong, light, and resistant to corrosion. However, they are complex, anisotropic materials: They can deform and degrade via a variety of damage and failure modes, and their performance can be affected by macro-, meso- and micro-structural properties such as fibre architecture – as well as by specimen geometry, loading configuration and environmental conditions. Wider use of FRPs is limited by the need for accurate and reliable predictive modelling, which in turn relies on good experimental data. However, their inherent complexity and structure means they are not necessarily suited to the usual suite of high-rate 'materials characterization' tests, as the concept of a wholly bulk-representative specimen may not be applicable. Indeed, we should arguably consider FRPs as structures, rather than materials in the traditional sense. To explore this issue, this paper considers the effects of specimen geometry, fibre weave, ageing and strain rate on mechanical response to compression. [ABSTRACT FROM AUTHOR]

The use of recycled concrete aggregate has positive environmental and economic contributions to the sustainability of the materials. However, when recycled aggregate (RA) is used instead of natural aggregate, the mechanical and structural performance of concrete are negatively influenced. Therefore, the development of practical techniques that reduce these negative influences are very important. Due to the confinement effect, the mechanical behaviors of the RA can be improved by encasing it in a circular steel tube. This paper describes a series of comparison tests on steel tubular columns of circular sections filled with normal self-compacting concrete and recycled aggregate self-compacting concrete. Ten specimens consist of 5 recycled aggregate concrete filled double skin steel tubular (RACFDST) columns and 5 normal concrete filled double skin steel tubular (CFDST) columns divided into three groups according to the type of load were tested under (axial, uniaxial, and biaxial) compression loads. Loading eccentricity and full replacement of natural coarse aggregate with recycled coarse aggregate were the main parameters in this study. Overall, the failure mode, ultimate capacities, and general deformational behavior have been presented in this paper. The results clearly showed that the failure mode of the RACFDST columns is generally similar to their normal CFDST counterparts with a slight reduction in ultimate bearing capacity. Specimens under axial compression were subjected to local buckling failure, while the global buckling failure was the mode of all eccentrically loaded columns. As expected, due to the confinement effect of the steel tubes, the strength of the sandwich concrete was enhanced, and all tested columns exhibited ductile failure. [ABSTRACT FROM AUTHOR]

According to available literature, it is assumed that outer packaging container, which is usually made of corrugated cardboard, does not influence the mitigation of the impact effects, thus in the designing process of packaging system the outer packaging is skipped. The purpose of this paper is to verify the above assumption, including determination of the influence of the 5-layer cardboard on the properties of structures that consist of that cardboard and polyethylene foam. Verification is performed with the use of the finite element method. To apply this method the dynamic compression curve of cushioning material is required. Therefore in the paper it is also presented the modified method to determine the curve. [ABSTRACT FROM AUTHOR]

In this paper, buckling analysis of composite stiffened panel with different shapes stiffener under uniaxial compressive load was carried out. Buckling behavior of straight stiffened panel on different shape of stringers were studied and compared. Stiffeners are providing the stiffness to the stiffened panel. In this paper several types of shapes like Z- shape, L-shape, Hat shape, I-shape, C-shape, J-shape and T- shape were taken. Numerical analysis done by non- linear software (ABAQUS 6.14-1). Main motive of this paper understands the shape of stringers and influences of the shapes in buckling strength. Influences of stiffener with various cross section areas of stiffened panel were deciding the buckling strength of the panel. Once buckling strength was improved, relatively high stiffness of assembly is also improving. Closed sections and more fasteners providing high buckling loads. [ABSTRACT FROM AUTHOR]

In this paper, a finite element model for the amphibious aircraft spreader bar using a composite structure will be presented. The initial spreader bar cross-section is an ellipse with an overall thickness of 3.8 mm and an additional thickness on the minor axis. The spreader bar using a composite structure is proposed to replace the initial spreader bar using aluminium. Composite Toray-TCA T700S-12K-50C#2510 Plain Weave Fabric will be used to replace aluminium 6061-T6. The composite spreader bar cross-section is similar to the initial design by applying ply drop-off to vary the thickness of its cross-section. There are 44 plies for the thick zone and 18 for the thin zone. For stacking sequences, all zones use symmetric layers. Model verification has been performed by comparing the spreader bar cross-section from the computer-aided design and finite element model. The spreader bar is modeled with a 2D shell element to obtain the failure index and margin of safety using Tsai-Wu failure criteria. The side load while landing will be used in this paper because it is a critical load during the flight. The side load generates tension, compression, shear, roll moment, yaw moment, and torsion in the spreader bar structure. The spreader bar structure using composite material is 42.8% lighter than using aluminium. The margin of safety of spreader bar structure using aluminium and composite material are -0.37 and 1.54, respectively. This results mean that composite structure can be used as an amphibious aircraft spreader bar, which is safer than aluminium in terms of strength, but not better in terms of stiffness due to its lower elastic modulus than aluminium. [ABSTRACT FROM AUTHOR]

St12T steel (X22CrMoV12-1) is characterized by high resistance to deformation, including the ability to withstand mechanical loads at high temperatures above 550 °C, which justifies its widespread use in turbine components. The main aim of the paper is determination of the model material coefficients for steel St12T after termo-mechanical exploitation. For this purpose it has been carried out termo-mechanical compression test. Afterwards the termo-mechanical compression test was repeated using tools CSD (Computational Solid Dynamics) in a numerical simulations. In the present simulation a modified Chaboche viscoplasticity model with hardening has been used. In the paper it is shown simulation of the experimental probe with a cylindrical shape, distributions of temperature, analyzed the status of the stress effort and plastic strains. The results of simulation compared with chart from termo-mechanical test is presented. [ABSTRACT FROM AUTHOR]

The numerical analysis of the composite materials is generated and structural analyses are carried out with the help of ANSYS ACP-Pre 17.2 and Structural analysis tool. Composite materials are widely used for their high strength to weight ratio and their tensile and compressive stress handling capacity. In order to achieve more strength and load-carrying capacity, the multi-layer composites are being used nowadays. In this paper, the comparative analysis between Carbon fiber, Glass fiber and Kevlar fibers are carried out for both conventional and hybrid composites. The ASTM D3039-76 standard specimen is taken for the analysis and the contours of total deformation (TD), equivalent stress (ES), normal stress (NS), equivalent elastic strain (EES), and strain energy (SE) with respect to tensile and compressive load are taken for each composite material and compared. Finally, the results are compared and the composite material suitable for tensile and compressive applications is optimized. From the analysis, it is observed that CFRP-UD-Wet and its associate's hybrid composites have the least structural outcomes when subjected to tensile and compressive loads. [ABSTRACT FROM AUTHOR]

This paper evaluates the behavior of non-structural masonry built with horizontal hollow clay bricks. The aims of the study are to reduce the structural vulnerability of houses built with this type of bricks in seismic zones of Latin America, especially Colombia and Ecuador. The tested specimens were 50 centimeters wide, approximately 10 centimeters thick and 1 meter high. The retrofitting methods consisted of two types of reinforcement: the first one with a 3:1 sand:cement ratio. (S:C) mortar overlay with 2.5 centimeters thick for overlay the welded wire mesh (WWM) (ϕ4mm/15cm) adhered to the masonry with plastic anchors on each face of the wall. The second one with the use of mortar overlay reinforced with steel fibers (SF20) using a dosage of 20 kg/m3, with an average thickness of 2.5 centimeters and a 3:1 S:C ratio. The experimental program included the testing of 13 axial compression specimens, 4 prisms for compression with WWM reinforcement, 4 prisms for compression with SF20 reinforcement, 4 with plain mortar overlay and 1 control masonry without any type of reinforcement, only with hollow bricks. Each type of reinforcement was assessed using a monotonic quasi-static axial compression test and 3 quasi-static cyclic tests. The results showed that SF20 reinforcement increases the compressive strength, controls crack growth, but the failure mode is fragile. On the other hand, the WWM reinforcement shows a lower compressive strength, but a less fragile failure mode since the more cracks are visualized and their size increases as the load increases in the test. This is also evident in the load-deformation curves. The WWM reinforcement does contribute to life safety, by holding the collapsed clay block fragments between the mortar diaphragms. In addition, it was observed in the experimental tests that the resistance can be increased by ensuring a continuous anchorage that holds the WWM on both faces of the horizontally drilled bricks. Finally, as a conclusion, the increase of resistance by SF20 reinforcement generates stiffer prisms for compression, but it would not guarantee life protection in case of cracking or collapse of masonry walls; on the other hand, WWM does allow greater deformations, despite not having a similar resistance as the walls reinforced by SF20. [ABSTRACT FROM AUTHOR]

The research reported in this paper is regarded as a series of tests, highlighting the application of nickel slag along with superplasticizer-blended cement-based paste in the production of porous concrete. Performance at the early age of three and seven days related to compressive strength, elastic modulus and position ration serves as the focus of discussion in this paper. The results indicate the satisfied outcome in appearance and shape resulting in a good performance of porous concrete made of slag nickel and natural crushed coarse aggregates to bear compressive loads at the early age of three and seven days. It is thus confirmed that the hydration process in the superplasticizer-blended cement-based cement paste results in the stronger binding to nickel slag from the early age of three to seven days. The modulus of elasticity reported in this study provides an input in the design criteria for the application of porous concrete at the early age. [ABSTRACT FROM AUTHOR]

This study investigates the application of carbon fiber reinforced polymer CFRP sheets to repair the damaged two-way reinforced concrete RC slabs under cyclic compression loads. The experimental work includes testing six RC slabs with the dimensions 1050x1050x70 mm and reinforcement φ8@150mm. All slab specimens were tested as simply supported on all four sides and were subjected to a concentrated load. In this paper, two specimens served as reference slabs without repair; one was tested under static loading to determine the ultimate load, and the other was tested under the repeated load RL. The four slabs were tested under repeated load RL. The parameters tested include slab damage rate (50- 75) % and repair configuration (orthogonal and parallel scheme). The experiment results showed that the use of CFRP sheets led to an increase: in the bearing capacity of damaged slabs, the stiffness at cracking, the cracking load, and stiffness after yielding load, respectively. And the best results were when using the orthogonal repair configuration in rehabilitating the damaged slabs with a 75%. [ABSTRACT FROM AUTHOR]

This paper presents a comparative performance study with the standardized emission results of a controlled output of 7.4 KW, a stand-alone diesel engine equipped with biodiesel (B100) and diesel fuel. Biodiesel was used in this study is produced from transesterification-processed Pilliostigma Thonningii (PT) oil. The tests were performed at full load for different compression ratios of 18:1, 19:1, 20: 1. Impact of these compression ratios affecting the performance parameters like brakes thermal efficiency, BSFC and emissions such as CO, CO2, HC, NOx and Smoke. The compression ratio that provides better performance and less emission have been identified. The results show higher break thermal efficiency, reduced fuel consumption and a growing trend in CO2 and NOx emissions. [ABSTRACT FROM AUTHOR]

The paper studies the behavior of a pivotally supported rod, the ends of which are fixed in the longitudinal direction under the action of a compressive load. The stability of a centrally compressed rod with an incompressible axis is considered if transverse reactions occur during buckling that are proportional to its deflections. It is assumed that these reactions are distributed along a vertical axis parallel to the axis of the rod and are determined by the coordinates in three-dimensional space x, y, and z. The equations are used, taking into account which it is possible to study the buckling of the rod in the case when the axis around which the cross sections rotate during the buckling does not shift. The condition is assumed that if the compressive force differs little from the critical load, then the resulting curved form of the rod equilibrium differs little from the rectilinear one, and the usual approximate expressions can be used to express the curvature. It is shown that in this case, the buckling of the rod in the planes of symmetry does not depend on torsion. When studying the stability of the rod under the action of end forces, it is shown that even in the first approximation, the results are close to the exact solution of F. S. Yasinsky. The stability of the supported rod is analyzed when the intensity of the longitudinal compressive load changes according to a linear law. The author believes that buckling occurs at a non-deformable surface. [ABSTRACT FROM AUTHOR]

This paper presents an investigation finding on the mechanical properties of BIB walls under compressive load. BIB refers to a new interlocking masonry unit design with multiple biaxial geometries of a groove and tongue to cater for a load. The multiple biaxial geometries allowed BIB to provide load resistance on the x and y-axis. In this study BIB unit was used to build a wall at the dimension of 1400 mm (L) x1500 mm (H) x 100 mm (T). The BIB wall was loaded with compressive load to evaluate the mechanical properties specific to compressive strength, flexural strength and Modulus of Elasticity (MOE). All data obtained on BIB wall properties investigated were then compared with normal cement sand brick walls. The properties of the BIB single unit were identified and present in this investigation. From all the data and analysis carried out, it is found that the utilization of BIB as a wall unit has successfully improved the compressive strength, flexural strength and MOE of the wall as compared to normal cement sand brick walls. The improvement level of the BIB wall to the cement sand brick wall was also presented. [ABSTRACT FROM AUTHOR]

Confined concrete technology significantly improves the properties of concrete in terms of compressive strength, tensile strength and flexural. It also makes the concrete more ductile, and more durable as it gives better resistance to acid and sulfate attacks. This paper provide an experimental study on the performance of concrete specimens confined by carbon fiber tube impregnated with a geopolymer adhesive under axial compression load after exposure to sulfuric acid attack for (30, 60, and 90) days. Fourteen cylinder concrete specimens with dimens ion 100mm×200mm were studied, that divided in to two groups, the first, included eight specimens were confined via two -layers of carbon fiber reinforced with geopolymer adhesive tube, and the other group was six specimens were unconfined. The results ind icated that the effect of erosion increases with the increase in the period of exposure to acids -attack. Also, the confined specimens gave a slightly decreas ing in compressive strength estimated by (4% to 9%). Finally, it becomes clear that the carbon fiber tube reinforced with geopolymer adhesive showed good anti-acid behavior, provided protection to concrete from corrosion i.e more durable, which increases the efficiency of the structural section subject to acids attack. [ABSTRACT FROM AUTHOR]

This paper investigates how concrete behaved when a carbon fiber reinforced geopolymer adhesive tube confined it. The effects of ground granulated blast furnace slag content on the geopolymer adhesive that used to reinforce the carbon fiber tube were investigated. The experimental program included, twenty-four cylinder concrete specimens confined by two layers of carbon fiber tube. Two specimens were confined by carbon fiber reinforced epoxy adhesive (CFREA) tube and twenty -two specimens were confined by carbon fiber reinforced geopolymer adhes ive (CFRGA) tube. Eleven mixes of geopolymer adhesive were prepared with replacement (0% to 100% by increment 10%) of binder by slag. Confinement specimens were tested under compression load. Based on the test results, the optimal geopolymer adhesive was found at the specimens confined by carbon fiber tube reinforced with a fully slag based geopolymer adhes ive, gave a s ig nificant axial stress enhancement ratio and deformation capacity by (2 and 10 times) respectively, which exceeded axial stresses of specimens confined by carbon fiber tube reinforced with fly ash based geopolymer adhesive tube by about (35%), which constituted about (98%) of epoxy adhesive tube. Finally, it is worth noting that it could be considered the geopolymer adhesive as a sustainab le and effective alternat ive to epoxy adhesive in concrete confinement techno logy. [ABSTRACT FROM AUTHOR]

CFRP lattice shell structures are preferred in spacecraft applications such as rocket interstages, payload adapters in launch vehicle, fuselage components. There is a necessity to improve the structural efficiency of these structures to withstand various loads, especially axial compression. This paper presents the Finite element modeling of CFRP composite cylindrical shells viz., unstiffened and anisogrid under static loading condition. Finite element analysis of unstiffened and anisogrid composite shell structures was conducted using ANSYS® workbench for axial static loading condition. The material model and material properties of the entire finite element analysis is based upon the literature test data results. Based on the Finite Element Analysis results it has been inferred that the anisogrid shell possess maximum load carrying capacity than unstiffened shell structures. [ABSTRACT FROM AUTHOR]

Several difficulties faced the researchers when tested a small and thin specimen in compression testing device. They had problem of interaction between two different tissues, when they were used to enhance the height of the specimen during previous studies. Therefore, some of them forced to use the high load device for the small specimen and this was not accurate and cost too much. According to the significant of the compression test in finding the mechanical characteristics of the specimen, therefore this paper focuses on designing and manufacturing of low load compressive testing device, low cost and tabletop design. The device will use not only for the soft tissue but also for synthetic materials such as composites and elastomers, some of biomaterials, tissue samples and tissue-engineered constructs and other soft materials. The mechanical and electronic parts of the device selected carefully to suit the measuring requirements. The device controlled by the computer application using visual studio 2019 to start the test and display the results. A significant accurate reading of soft tissue specimen had provided by using digital dial gauge and high sensitive load cell for displacement and force measurement respectively as compared with standard reading of previous studies. Moreover, the results had been drawing as load-distance curve or could be saved by the application to the Microsoft Excel to get more results and give broader understanding of the material's properties. In this paper the designed device test; articular cartilage, tendon and liver specimens got maximum load at 78.76N, 397.23N and 15.73N respectively. In addition to these specimen the glass ionomer had been tested to find the ranges loading of the device. In conclusion, the range reading of the designed device was from 0N to 1500N. The device had a good validation, after comparing the results of different specimens (articular cartilage, tendon, liver and glass ionomer) with previous studies results (using other devices) and give the same range the error percent of the device was less than 5%. [ABSTRACT FROM AUTHOR]

Theoretical researches of operating processes of slow-speed reciprocating compressor stages with linear drive, conducted by the authors of this paper, have determined the experimental confirmation necessity for gas compression possibility in one stage up to pressure 10.0 MPa and above at atmospheric suction pressure. The testing results of the newly developed experimental slow-speed piston compressor stage with linear hydraulic drive are presented in the paper at the ratio of the discharge to suction pressure values from 50 to 100. [ABSTRACT FROM AUTHOR]

This paper presents an experiment on the dove tail profiled steel concrete composite shear wall (DSCW) under axial compression. Four DSCWs specimens were designed and constructed in order to test and obtain the deformation behavior, failure modes, bearing capacity, stiffness changes, etc. The results indicate that the failure process of all 4 specimens is initialed from steel sheets local buckling to the final concrete crushing. The steel and concrete can work consistently because the dove-tail-shaped ribs of the sheets have a good anchoring effect on the concrete. Based on the experiment result and analysis, a simplified formula for DSCWs was suggested to calculate the axial compressive strength with consideration of the influence of local buckling of steel sheets. [ABSTRACT FROM AUTHOR]

Analysis and understanding of the behavior of piles and prediction of their bearing capacity under the influence of different loads are important tasks in the design of foundations. Generally, piles are used for two purposes: firstly, to improve the bearing capacity of the pile foundation, and secondly to lower the settlement of the foundation. This paper investigates the behavior of pile load capacity under the influence of axial compressive loads where various parameters were considered. The studied parameters are the pile length, the end condition (close-ended circular pile, open-ended circular pile, close-ended square pile, open-ended square pile, and H-pile) for different length-to-diameter ratios (10, 13, and 16). Also, the failure time for piles was included. The tests were carried out in fully saturated soil. A total of 15 experimental tests were conducted to evaluate the performance of pile models under the influence of compressive loading. It can be concluded that the bearing capacity of the model pile increases with increasing length-to-diameter ratios. Additionally, the close-ended pile has higher capacity than an open-ended pile by 36.9%, 17.7%, and 4.35% for length-to-diameter ratios of 10,13, and 16 respectively. [ABSTRACT FROM AUTHOR]

The paper aims to examine the initial buckling progress of the square plate on a centrally placed cutout of elliptical shape with combined loads (–ve shear load and uniaxial compression). The influence of the orientation of elliptical cutout, cutout geometric ratio and cutout position in various laminated square plates on which buckling load was analysed. The result shows that the magnitude of the buckling load is higher by enlarging the angle of the cutout in all types of laminates. By extending the c/a ratio at a larger angle of the cutout, the buckling capacity magnitudes are increasing whereas, for the smaller angle of c/a ratio, the load is declining. By extending the b/a ratio, the magnitudes of the buckling load are decreasing. The cross-ply laminate [(0°/90°)2]sis impregnable than the angle ply laminate [(45°/- 45°)2]s and Quasi-isotropic laminate (45°/-45°/0°/90°)2 irrespective of the orientation of the cutout, the geometric ratio (b/a and c/a) and cutout position. [ABSTRACT FROM AUTHOR]

This paper studies the potential of using carbon black filled polymers as pressure sensors. Changes of their properties under compressive load are investigated. It is found out that the dependence of volume electrical resistance of materials on applied pressure is linear if the applied pressure is less than three atmospheres. Stronger pressure brings nonlinearity and more distinct changes of volume electrical resistance. The sensitivity of composites to applied compressive load can be controlled by adjusting the carbon black filler concentration. It is revealed that changes of volume electrical resistance values under compressive load can be both monotonous and non-monotonous. For the monotonous case, volume electrical resistance changes nonlinearly along with the increase of pressure. The difference of electrically conductive constituent concentration has a weaker influence on changes of volume electrical resistance under compressive load than on resistance variation in a sample set of same-type materials. Rubber matrix type has a greater influence on the changes of volume electrical values than the carbon black filler type. Recommendations on the selection of components for resistive composite polymers are elaborated using the results of the conducted research. The recommendations can help to produce pressure sensors with required volume electrical resistance values along with minimal variation in a set of same-type equipment. [ABSTRACT FROM AUTHOR]

This paper presents the results of laboratory tests and finite element (FE) analyses of concrete cylinders subjected to compression. The laboratory tests of concrete elements were conducted to determine the secant modulus of elasticity and the nonlinear stress–strain relationship for concrete. This relationship was used to validate the numerical model of the concrete cylinders subjected to compression. The comparison between the numerical and experimental results indicates that the adopted 3D model captures the response of the concrete cylinders subjected to compression fairly well. [ABSTRACT FROM AUTHOR]

In geotechnical engineering, ground improvement means treatment of the subsoil underlying the fill to improve the bearing capacity of the subsoil to decrease the settlement. Heretofore, a wide range of various kinds of techniques have been introduced to improve the properties of weak soils and all come with some advantages and disadvantages. In this paper, a commercial FEM program, Plaxis 3D V20 has been used to simulate one of the most economical and effective techniques, called preloading. In the case of the existence of soft soil layers or soils with low permeability in the geological profile and due to consolidation settlement, treatment often takes a long period of time. In such circumstances, pre-fabricated vertical drains can be employed together with the application of the surcharge to shorten the duration of the process. At the beginning of this research, an as-built road embankment that is located on the R2 highway in Slovakia is simulated and the result of the numerical model is compared with the inclinometer measurements installed in the field. Furthermore, compression surcharge load equal to 1.2 times higher than the pressure of the actual structure in combination with a group of prefabricated vertical drains (PVD) are considered to shorten the drainage path and consequently decrease the consolidation time rate. When the consolidation is over, the surcharge will be removed and replaced with the actual embankment fill. In the end, the results of the time-dependent analysis including graphs of vertical deformation, effective stress, and excess pore pressure versus time are plotted, and efficiency of the technique is discussed. [ABSTRACT FROM AUTHOR]

Hydrocode calculations require knowledge of the variation of pressure of a material with density and temperature, which is given by the equation of state. An accurate model needs to account for discontinuities in energy, density and properties of a material across a phase boundary. When generating a multiphase equation of state the modeler attempts to balance the agreement between the available data for compression, expansion and phase boundary location. However, this can prove difficult because minor adjustments in the equation of state for a single phase can have a large impact on the overall phase diagram. Recently, Cox and Christie [1] described a method for combining statisticalmechanics- based condensed matter physics models with a stochastic analysis technique called particle swarm optimization. The models produced show good agreement with experiment over a wide range of pressure-temperature space. This paper details the general implementation of this technique, shows example results, and describes the types of analysis that can be performed with this method. [ABSTRACT FROM AUTHOR]

To complement the creep performance of ultra-high strength concrete, the long creep process of fiber reinforced concrete was studied in this paper. The long-term creep process and regularity of ultra-high strength concrete with 0.5% PVA fiber under the same axial compression were analyzed by using concrete strength (C80/C100/C120) as a variable. The results show that the creep coefficient of ultra-high strength concrete decreases with the increase of concrete strength. Compared with ACI209R (92), GL2000 models, it is found that the predicted value of ACI209R (92) are close to the experimental value, and the creep prediction model suitable for this experiment is proposed based on ACI209R (92). [ABSTRACT FROM AUTHOR]

In this paper, a multivariable model-based non-linear controller for Warm Compression Stations (WCS) is proposed. The strategy is to replace all the PID loops controlling the WCS with an optimally designed model-based multivariable loop. This new strategy leads to high stability and fast disturbance rejection such as those induced by a turbine or a compressor stop, a key-aspect in the case of large scale cryogenic refrigeration. The proposed control scheme can be used to have precise control of every pressure in normal operation or to stabilize and control the cryoplant under high variation of thermal loads (such as a pulsed heat load expected to take place in future fusion reactors such as those expected in the cryogenic cooling systems of the International Thermonuclear Experimental Reactor ITER or the Japan Torus-60 Super Advanced fusion experiment JT-60SA). The paper details how to set the WCS model up to synthesize the Linear Quadratic Optimal feedback gain and how to use it. After preliminary tuning at CEA-Grenoble on the 400W@1.8K helium test facility, the controller has been implemented on a Schneider PLC and fully tested first on the CERN's real-time simulator. Then, it was experimentally validated on a real CERN cryoplant. The efficiency of the solution is experimentally assessed using a reasonable operating scenario of start and stop of compressors and cryogenic turbines. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO. [ABSTRACT FROM AUTHOR]

The paper is devoted to the study of operability of Fiber Bragg Grating (FBG) sensors embedded in concrete cylindrical sample under uniaxial compressive load. The data received from FBG sensors was compared with surface mounted strain gauges. Also the reliability of the FBG readings was established. During long period of time (more than one year) the integrity and optical properties of fiber-optic sensors were tested. A distinctive feature of this study was that fiber-optic line, which was embedded into sample at the manufacturing stage, did not have any special protective coatings only traditional polyimide protective coating. [ABSTRACT FROM AUTHOR]

Sandwich structures, which typically consist of two thin flat plates separated by a core, are commonly used in applications where the light weight considered as one of the influential design criteria. The core is usually designed in a certain way, allowing the structure to withstand the applied loads and to dissipate energy. The main function of the core in the sandwich structure is to redistribute the applied force by deformation and to dissipate the impact energy. The objective properties of sandwich cores are high stiffness to weight ratio, high bending stiffness, and high energy absorption ratio. The conventional designs of sandwich cores, such as foamed cores, honey-comb, and ribbed cores, have been used for many decades. Origami inspired sandwich cores have attracted attention during the last years, due to their high capacity for elastic deformation, force redistribution, bending and twisting resistance. In this paper, we present the results of a quasi-static compression test, and the energy absorbed by Muira origami folded cores, made by direct molding of polymeric blends. The material compositions used were polylactic acid (PLA) and thermoplastic polyurethane (TPU), and the weight percentage of these compositions were (100/0, 80/20, 65/35, 50/50, 20/80, and 0/100) (PLA/TPU). It has been found that cores with high PLA content have high stiffness values, while the cores with high TPU content have the high energy absorptions efficiency. [ABSTRACT FROM AUTHOR]

Hemp is an agricultural product used for various applications. In the Civil Engineering field, only a limited use of this natural material, called the "green pig" since exploitation of all its constituent parts is allowed, has been done. For this reason, in the paper an experimental activity on lime mortars and bricks reinforced with hemp components has been performed. Compression and bending tests have been carried out on specimens manufactured with hemp shives and fibres, respectively. The achieved results have shown that hemp products change the failure modes from brittle to ductile, leaving basically unaltered the strength capacity of reinforced specimens with respect to unreinforced ones. [ABSTRACT FROM AUTHOR]

In this paper, we proposed an effective approach to numerical investigation of the debonding process in composite laminates under quasistatic loading with usage of the cohesive zone model. It is based on contact interaction of the coinciding reference surfaces of two interconnected shell-layers. The cohesive zone model is intended to define a stick area where potentially the debonding can occur. This approach was realized in the ANSYS® commercial software and was verified on the test models, which usually apply to experimental investigation of the fracture process. Both the buckling phenomenon and postbuckling behavior of the ply separation are considered in thin-walled laminated plate under 4-point bending. By using the proposed approach, the defect propagation is investigated, which is caused by the ply separation buckling. [ABSTRACT FROM AUTHOR]

Drop damage resistance is experimentally found and breaking stress is determined in radial compression tests for green and dry chrome concentrate briquettes. The paper studies the influence of compaction pressure and the amount of the binder on compactibility in the testing of cylindrical briquettes. The aim of the study is to determine optimal briquetting process conditions for the production of high-quality metallurgical briquettes by roll briquetting. [ABSTRACT FROM AUTHOR]

Refer to the thin element of cold-formed steel elements, the phenomenon of local buckling and post-buckling be a serious concern on structures. Thin elements undergo local buckling before melting stress while receiving a bending load, tension/compression, or shear around the support. The instability of local buckling caused the post-buckling on structures. Unlike ordinary hot-rolled, cold-formed steel structures normally buckle before yielding but the compression elements do not collapse despite buckling. The additional load could be supported by the elements after buckle through the stress distribution. Post-buckling strength can be several times greater than the force caused by the local buckling critical stress. On the effectiveness width approach, it is assumed that the total loads are supported by the fictitious width bf experiencing at uniformly maximum stress. In this paper, the flexural buckling behavior of cold-formed steel is investigated by numerical modeling using a finite element analysis of software. A Thin element with a ratio of depth (h) to width (bf) great could cause a local buckling element. Local buckling of elements accumulates causing post-buckling structure, which works simultaneously with torque. The h/bf ratio of 3 has better resistance to buckling elements than it of 2. [ABSTRACT FROM AUTHOR]

This paper carried out the research on the axial load carrying capacity of the (CFDST) concrete filled double skin cold formed column with steel inner tube when subjected to compressive loading. CFDST column involves two concentric tubes with sandwiched concrete between them. The steel provided at the outer skin section impart stiffness and strength, the inside skin increase the ductility and in between the concrete contribute local and overall stability to the system. Finite element analysis of sandwich structure with cold formed steel is done using ANSYS. The results acquired from the finite element analysis are compared with the section capacities predicted by using simplified models. Performance compared between the CFDST column and CFST columns were presented. Good agreement in the results was found between the finite element analysis and theoretical investigation. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of the sensitivity of strain gauge force sensors to bending moment which badly affects the measurement accuracy. The bending moment sensitivity can be caused by incorrect force sensor geometry, suboptimal arrangement of strain gauges, imprecise positioning of strain gauges during installation, variation of the strain gauges’ properties. In this study we investigate the effects of the strain gauges’ positioning errors and variation of their properties on the bending moment sensitivity for the case of a compression membrane force sensor having axis-symmetrical geometry. Firstly, we obtain the information about the sensor’s stress-strain state when it is loaded with compressive force and bending moment using Finite Element Analysis. The Finite Element Analysis results are used in conjunction with probabilistic modelling techniques for evaluation of the distribution of the bending moment sensitivity. The modelling results have shown that the distribution’s mean value is approximately zero due to the axis-symmetrical geometry of the force sensor. The standard deviation of the bending moment sensitivity depends on the number of strain gauges in the Wheatstone bridge and the gradient of the strain caused by bending moment in the areas where the strain gauges are installed. The proposed method of evaluating bending moment sensitivity can be applied to other kinds of parasitic loads and other types of strain gauge force sensors for minimizing the sensitivity to parasitic loads in single- and multi-axis strain gauge force sensors. [ABSTRACT FROM AUTHOR]

The ship hull is the basic underlying structure of ship that makes the ship water tight or water proof. Meaning the hull prevents the water from entering the cargo, machinery.so hull are usually made of materials that have high mechanical properties, impact less and less water absorption qualities.conventional hull materials used where steel wherein the boat becomes too heavy in considerations with its high strength, abrasion resistance etc.so composite materials where used which give a single structure offering solutions of strength, durability, light speedy, watertight structure in the manufacturing of boats for past 50 years. This novel paper focuses on a comparative study of composite materials previously used with further improvements in characteristics such as increased strength, ease of manufacturing, more impact resistance and increase is load tensile and compressive load bearing characteristics. The composite materials comprising of GFRP+graphite powder and GFRP+Aluminum powder was tested and analyzed experimentally for enhancement in various mechanical properties, structural and water absorption capabilities, and optimum designs further obtained. Even though experimental analysis where performed numerical analysis of these composite models is yet to done which would lead to determining more efficient structures with best materials used. [ABSTRACT FROM AUTHOR]

The paper presents a numerical model of the response for brittle materials to dynamic mechanical loading and implementation of the model within the discrete element method (DEM) by the example of the movable cellular automaton method (MCA). Verification of the model was carried out using the numerical modeling of the uniaxial compression tests of concrete and sandstone samples at various strain rates. It is shown that the developed model is correct and adequately describes the behavior of brittle materials under dynamic loading. [ABSTRACT FROM AUTHOR]

In this paper the study of cold flow simulation for internal combustion engine with computational fluid dynamics code integrated with ANSYS to obtain very useful results using a modeled engine. In order to improve engine quality, understanding on flow properties in engine cylinder is of major importance because flow condition significantly influences engine efficiency, Capabilities in providing optimum flow conditions which include high discharge coefficient, optimum swirl ratio, and optimum tumble ratio in respective engine can result in enhancement of engine power and comfort, along with reduction of fuel consumption, exhaust emission and noise. The simulation is applied for a geometry with cylinder bore (100mm), stroke length (100mm), inlet valve diameter (30mm), exhaust valve diameter (20mm), valve seat length (2mm) and valve orientation is inclined at from vertical 28°, valve guide diameter (10mm), which is developed to study the effect of valve lift and the effect of valve orientation on the flow of fluid inside the cylinder. Cold flow analysis occurs in engine cycle with moving geometry, air flow, and no fuel injection or reactions. Simulation analysis represents the flow properties in term of swirl ratio and tumble ratio. [ABSTRACT FROM AUTHOR]

This paper illustrates the optimal method for calculation of buckling load in thin cylindrical shell. In addition to experimental setup, the various imperfections of geometrical structures of specimen is discussed and analyzed using coordinate measuring machine. Different types of finite element models depending upon their complexity are used for simulation in an attempt to have good results when compared with experimental buckling loads. Parameters such as measuring the effect of initial geometric irregularities, eccentricity of load, as well as measuring eccentric load along circumferential direction of shell and arrangement, often influenced boundary condition strategies. Effects of measuring the initial geometric imperfections and load eccentricity often revere the experimental buckling load prediction when demonstrated with simplified rigid support conditions. This work also illustrates the dependency of eccentric load position and imperfection in geometry on circumferential direction while buckling load is applied. [ABSTRACT FROM AUTHOR]

Delamination phenomenon as one of the failure mechanisms in hybrid Fiber Metal Laminate structures had been already recognized. It occurs in structures under various type of loading. This paper presents numerical investigation on the buckling and postbuckling behaviour of FML channel section column with implementing of delamination process. Delamination was applied to the model by contact elements using Cohesive Zone Method. Linear buckling analysis and nonlinear buckling analysis with implementation of geometric and material imperfections were performed. [ABSTRACT FROM AUTHOR]

The effects of perforation position on the compressive load carrying capacity of cold-formed lipped channel sections are studied and discussed. Cold-formed steel sections have become competitive structural components in the modern building construction due to their inherent favourable characteristics over conventional hot-rolled steel members. However, the advantages of these members are often limited due to the presence of perforations. Due to the position of perforations, ultimate strength and elastic stiffness of a structural member can be varied. This paper describes the ultimate strength results obtained from numerical, theoretical and experimental investigations for fixed-fixed end condition. The numerical results were compared with the findings from the experimental investigation results, showed good correlation both with ultimate strength and failure modes. The study showed that the reduction in the stiffness associated with the specimen with perforations on the web was found to be lower than that for the specimen with perforations on the flanges. [ABSTRACT FROM AUTHOR]

The paper presents the results of an in situ investigation of the evolution of deformation fields during compression of cylindrical and dumbbell-like steel rods at meso- and macroscale levels using digital image correlation method. A different nature of distributions of localized strain regions on the sample surface during compression of cylindrical and dumbbell-like steel rods at stages II and III was established. It was revealed that the change in strain patterns on the sample surface during compression of cylindrical and dumbbell-like steel rods correlates with the stages on the “stress-strain” curves and reflects the change in strain mechanisms. [ABSTRACT FROM AUTHOR]

The paper presents theoretical studies on the operation of linear hydraulic drive by changing the ratio of the compression time (forward stroke) and the suction time (backward stroke). The influence of the drive operating mode on the working cycle efficiency is assessed. [ABSTRACT FROM AUTHOR]

The production technology of ceramic materials has a significant impact on the physical properties of the final products. This paper shows the differences in density and Young's modulus of samples made by five different compression pressures. Due to the increasing compression pressure, the particles are closer to each other therefore the porosity of the material decreases, and the density increases. The influence of the firing temperature and compacting pressure on density and Young's modulus of electroporcelain is studied after firing up to temperature 1200 °C with a heating rate of 5 °C/min for heating and cooling stage. The studied material is made from electroporcelain mixture. This mixture is often used in electotechnical industry for the production of high-voltage insulators. The samples are made under a pressure from 70 MPa up to 110 MPa. [ABSTRACT FROM AUTHOR]

The paper considers the stability problem of an arch shock absorber made of a rubber-like material. As a model, the nonlinear theory of thin shells from elastomers K.F. Chernykh is used. The case of symmetrical and asymmetrical deformation of an arch shock absorber under symmetrical compression is investigated. The possibility of asymmetric bifurcation is evaluated depending on the geometric parameters of the shock absorber. [ABSTRACT FROM AUTHOR]

In meso-scale finite element modeling, the yarns of the reinforcement are considered to be solids made of a continuous material in contact with their neighbors. The present paper consider the mechanical behavior of these yarns that can happen for some loadings of the reinforcement. The yarns present a specific mechanical behavior when under longitudinal compression because they are made up of a large number of fibers, Local buckling of the fibers causes the compressive stiffness of the continuous material representing the yarn to be much weaker than when under tension. In addition, longitudinal compression causes an important transverse expansion. It is shown that the transverse expansion can be depicted by a Poisson ratio that remained roughly constant when the yarn length and the compression strain varied. Buckling of the fibers significantly increases the transverse dimensions of the yarn which leads to a large Poisson ratio (up to 12 for a yarn analyzed in the present study). Meso-scale finite element simulations of reinforcements with binder yarns submitted to longitudinal compression showed that these improvements led to results in good agreement with micro-CT analyses. [ABSTRACT FROM AUTHOR]

The aim of the paper is to analyze experimental data on the dynamic response of the marble specimen in uniaxial compression. To make it we use the methods of mathematical statistics. The lateral surface velocity evolution obtained by the laser Doppler vibrometer represents the data for analysis. The registered data were regarded as a time series that reflects deformation evolution of the specimen loaded up to failure. The revealed changes in statistical parameters were considered as precursors of failure. It is shown that before failure the deformation response is autocorrelated and reflects the states of dynamic chaos and self-organized criticality. [ABSTRACT FROM AUTHOR]

This study discussed the evolution and important findings, critical technical challenges, solutions and bonding equipment of flip chip thermo compression bonding (TCB). The bonding force, temperature and time were the key bonding parameters that need to be tweaked based on the researches done by others. TCB technology worked well with both pre-applied underfill and flux (still under development). Lower throughput coupled with higher processing costs was example of challenges in the TCB technology. The paper is concluded with a brief description of the current equipment used in thermo compression process. [ABSTRACT FROM AUTHOR]

The paper deals with the rheological behavior and microstructure formation of a metal matrix composite (MMC) based on a matrix made of the V95 alloy (analogue of the 7075 alloy) with reinforcing SiC particles. The rheological behavior has been investigated from plastometric testing results on cylindrical specimen compression at temperatures ranging from 400 to 570 °C and strain rates ranging between 0.1 and 0.25 s-1. It has been established that the flow stress curve for a V95/10%SiC MMC consists of a few pieces at 400 and 570 °C. First there is material hardening, then there is softening followed by another portion of hardening. At a temperature of 500 °C, instead of a descending branch, on the flow stress curve there is a steady horizontal portion followed by hardening. Electron backscatter diffraction has shown that dynamic recovery and dynamic recrystallization occur in a V95/10%SiC MMC under deformation. Dynamic recovery is more active at 500 °C and 570 °C than at 400 °C due to the annihilation of dislocations, and this is reflected in the formed microstructure. [ABSTRACT FROM AUTHOR]

The paper is devoted to modeling of the structure and calculation of the stress-strain state of trabecular bone tissue fragments under uniaxial compression. The influence of the number of trabeculae nodes used in models on the value of their average longitudinal strain is studied. The results of the research are needed to develop recommendations for creating mechanically compatible implants. [ABSTRACT FROM AUTHOR]