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Higher efficiency of freight transportation can be achieved through the use of a hopper-type container. This paper presents the results of determining the dynamic loading for a container placed on a flat car during shunting impact. It was found that the maximum accelerations to a container in the longitudinal direction were 36.7 m/s2 (3.7g). The value of acceleration obtained was included in the strength calculation for the container. The maximum equivalent stresses of a container were concentrated in the areas where the bottom side rail interacted with the fittings; they were 315.1 MPa, thus they did not exceed the allowable values. The paper presents the results of the strength calculation for a container in the process of stacking. The maximum equivalent stresses in this scheme of loading were 245.3 MPa, which is lower than the allowable values. The authors suggest a lift-off roof on the container for transportation of freight requiring weather protection. The results of the strength calculation for the roof under the longitudinal loads demonstrated that the maximum equivalent stresses in it were 50.2 MPa, which is considerably lower than the allowable values. The research will be valuable for those who develop advanced container structures with better operational efficiency intended for container transportation. [ABSTRACT FROM AUTHOR]

The goal of the study was to replace traditional steel leaf springs with composite materials while maintaining their size and geometry. This paper represents the design and static analysis of the mono leaf-spring. A Metal Matrix composite P100 Gr/6061 Al has been used to compare the existing leaf spring made up of stainless steel. This paper aims to design and perform static structural analysis comparison between mono leaf spring made up of metal matrix composite (MMC) and existing material steel. The structural modeling and finite element analysis [FAE] of mono leaf spring has been performed in Catia v5 R20 software and then imported to the ANSYS 2022 R1 workbench resulting in the improvement of the design of mono leaf spring along with weight reduction. [ABSTRACT FROM AUTHOR]

In this paper the stress-strain state of a buried pipeline in a viscoelastic medium under the influence of harmonic waves is considered. Here much attention is paid to the long-wavelength and low-frequency analysis and dynamic behavior of a long cylindrical shell (continuous pipeline) located in a viscoelastic medium. The relationship between stress and strain satisfies the hereditary Boltzmann-Voltaire integral. The equations of motion of the environment satisfy the Lame equations with operator coefficients. The conditions of rigid (or sliding) contact are set on the contact. At infinity, the Sommerfeld radiation conditions are set. Techniques and an algorithm for the analytical solution of the problem have been developed. Based on the shell theory, it is shown that the dynamic forces of the hoop and axial stresses arising in the shell due to longitudinal (or transverse) traveling harmonic waves depend significantly on the ratio of the stiffness of the pipe and the surrounding soil. The results of stresses and forces, respectively, in the environment and the shell, depending on the direction of the incident waves, are presented for various values of Poisson's ratios and stiffnesses of soil and pipe materials. [ABSTRACT FROM AUTHOR]

This paper presents a theory for analyzing porous functionally graded (PFG), rectangular in plan, size-dependent shells at large deflections. Three types of porosity are considered in the study. The theory is based on the Kirchhoff-Love kinematic model, incorporating the modified coupled stress theory (MCST) to account for size-dependent factors. The PDEs that are valid for the shells are obtained by means of the Hamiltonian principle. To obtain reliable results, the governing partial differential equations (PDEs) are transformed into ordinary differential equations (ODEs) by means of the second-order finite difference method (FDM), the Bubnov-Galerkin method (BGM) in higher approximations, and either the variational iteration method (VIM) or the extended Kantorovich method (EKM). The numerical methods and algorithms are validated through convergence studies. Among the numerical methods employed, preference is given to the variational iterations method, specifically the extended Kantorovich method, for its effectiveness in obtaining accurate results. The study also investigates the influence of the porosity type, the size-dependent parameter, and the porosity index on the stress-strain state of nano-shells. Through analysis, the optimum type of pore distribution is identified, which can enhance the mechanical performance of the shells. The findings contribute to the understanding of the stress-strain state of nano-shells and the influence of porosity characteristics, ultimately aiding in the development of improved materials and structures. [ABSTRACT FROM AUTHOR]

Usually, the complete system of thermoelasticity equations consists of the equation of motion, the Dugamel-Neumann relations, the Cauchy relation, and the heat influx equation. In this case, usually the boundary value problem is reduced to a system of differential equations for displacements and temperature with the corresponding initial and boundary conditions. Coupled thermoelasticity problems can be formulated in both stress and temperature, but this requires the second order of smoothness of the stress tensor. In this regard, there is an additional condition regarding stress. In this paper, the coupled problems of thermoelasticity are proposed to be considered on the basis of the equations of motion, the continuity equation, the Dugamel-Neumann relation, and the heat influx equation. In this case, a system of three interrelated equations for stress, velocity and temperature was obtained. Based on this system, the problem of the stress-strain state of a homogeneous semi-infinite thermoelastic rod under the action of a dynamic thermomechanical load applied to the end of the rod is considered. The exact analytical solution was obtained by the continuation method followed by the application of the Laplace and Fourier integral transformations. The asymptotic behavior of the stress is studied for small and large values of time. The propagation velocity of a thermoelastic wave has also been studied. Numerical calculations are carried out, the qualitative and quantitative nature of the mutual influence of temperature on the distribution of stresses and velocities of the rod sections is analyzed. [ABSTRACT FROM AUTHOR]

This paper deals with the initial design and realization of a laboratory sample of a birefringent material-based stress sensor. A cube-like sample of commercial polycarbonate (PC) with a volume of approx. 1cm3 is used as an active medium providing information on the applied stress. The sensor uses the stress-induced birefringence of the PC sample for measuring the applied stress. The proposed sensor is calibrated by a commercial weighing element. The utilization of the element allows the conversion of the unknown applied load into a known mechanical stress value according to the known size of the sensing area. In the paper, we report the result of the calibration routine of the sensor sample and discuss the possible application areas. [ABSTRACT FROM AUTHOR]

This paper examines the stress-strain state of a pipeline inspection window made of polymethyl methacrylate (PMMA). Two cases are considered: without a defect in the thickness of the body under consideration; taking into account a small defect near the inner wall. The problem reduces to the Lamé problem, taking into account the physical nonlinearity of the material. Analytical estimates of the principal stresses in a cylindrical coordinate system for a defect-free body are given. Based on the obtained estimates, a numerical solution to a similar problem was verified using COMSOL Multiphysics. The problem of the influence of a defect on the stress-strain state of a body was solved numerically, taking into account the physical nonlinearity of the material, and the dependence of the safety factor on the position of the spherical cavity was shown. [ABSTRACT FROM AUTHOR]

Elasticity modulus, Poisson's ratio and shear modulus are important material constants needed in structural analysis to calculate stresses and strains. The first two of them are determined by a relatively affordable tensile test, and the third by a torsion test, which is less common in testing laboratories. There is a mathematical relationship between the three material constants, so only two of them are independent. This allows one of the three constants to be calculated if the other two are known thus saving some experimental work. Or, if all three constants are determined by experiment, to check the accuracy of the results obtained. In this paper, the most used methods and approaches of these material constants determination are presented and analyzed. Tension and torsion tests were carried out on S235JRC cold-drawn steel rods, with diameter of 6 mm. [ABSTRACT FROM AUTHOR]

The shock absorber is a key element of the car's suspension. Comfort, cornering stability and braking properties depend on its condition. In good condition, it must provide the necessary levels of damping for the relative displacement between the sprung and the unsprung mass of the vehicle. The reasons of a faulty shock absorber include a breach in the integrity of the seal between the different chambers, fatigue of the springs in the valve (piston) systems, plastic deformations in the working inner cylinder due to high temperature and mechanical stresses, etc. In the event of a shock absorber fault, usually there are no visual or noise changes to alert the driver. Therefore, the technical condition of the shock absorbers is often neglected. The visual inspection at annual tests of vehicle safety and roadworthiness does not give a satisfactory result. Expensive vibration stands are used to diagnose the technical condition of the shock absorbers, which also repels maintenance centers from such a purchase. The paper presents a comparative method that determines the technical condition of the shock absorber. For this purpose, the free damped oscillations of the sprung mass are recorded with measuring equipment at an affordable price. The measuring equipment includes an accelerometer, a DAQ-module and a laptop. The tyre is disturbed in the contact patch by artificial obstacles. Based on the logarithmic decrement of the oscillations, the damping coefficient of the suspension system is determined. Its value is an indicator for the technical condition of the shock absorber. [ABSTRACT FROM AUTHOR]

In this paper, it is proposed to evaluate the elastic properties of structures made of porous materials by creating an equivalent homogeneous model with effective elastic moduli found in accordance with the continuum hypothesis. This approach greatly simplifies calculations and facilitates the task of modeling the designed structure. A comparison of two methods for calculating the effective compression and shear moduli for a porous material is presented. The first method involves calculating the bulk compression and shear modules by solving two independent problems of deformation of a representative cell of a porous material by the finite element method. The second method is an analytical calculation for simplified representative cells. The possibility of presenting products with an internal porous structure as equivalently homogeneous for performing design calculations was verified by comparing the calculated values with the values obtained experimentally. An MBB (Messerschmitt-Bolkow-Blohm) beam of optimal topology with an internal porous structure was chosen as the object of research. Experimental samples of this beam were made with an internal filling of 10, 30 and 70%. Calculations of the stress-strain state of the beam were carried out according to the linear theory of elasticity. A two-component model of a beam, consisting of a shell with real elastic moduli and an internal porous structure with effective moduli, is proposed. The average deviation between the results of numerical calculations and experimental data for such a model did not exceed 6%. [ABSTRACT FROM AUTHOR]

Research on the compression behavior of concrete has been widely carried out, on the other hand, information about the behavior of concrete in tension was limited. The existing concrete tension tests are the splitting, direct tensile, and rupture tests. These methods provide information on the tensile strength of concrete through concrete tension stiffening tests. This paper aims to elaborate on the experimental study to develop and construct the equation of concrete tensile strength based on the tension stiffening effect mechanism. The basic principle of this newly proposed method was the composite action between steel and concrete. The straight and continuous steel bar was embedded in concrete to ensure no eccentricity that could interfere with research data due to the bending moment. 45 Specimens made from cylinder concrete with 101.6 mm diameter and 450 mm length, steel bar embedded at the center of the section. Three concrete mixes with actual compressive strength of 31.66 MPa, 40.27 MPa, and 46.60 MPa and steel bar diameters of 15.9 mm, 18.7 mm, and 21.7 mm were used as variables. The test was performed by applying an incremental tensile loading at both ends of the steel specimen with a load rate of 5-10 kN/minute to obtain a force-displacement relationship. The curve must be lessened with steel bar response to get the load-displacement of tension concrete, and then by dividing load with concrete area and displacement with the length of both LVDT can be generated stress-strain of tension concrete. This study shows that the tension-stiffening effect is affected by the reinforcement ratio. Where the reinforcement ratio increases, the tension-stiffening decreases. The steel bar to concrete-area ratio higher tends to more cracks. The concrete tensile strength of this research is taken from the stress of the first crack indicates very close to the direct tensile test but slightly higher. [ABSTRACT FROM AUTHOR]

In the practice of designing reinforced concrete structures is more widely used the beam model, so it showed to good advantage for assessing the bearing capacity of the structures. However, in some cases when a more detailed picture of the behavior of the structure is needed the beam model is not suitable by its mathematical nature, which is extremely one-dimensional. The paper deals with numerical approach in developing modern method for calculating of reinforced concrete structures taking into account the elastoplastic characteristics of the material. For more accurate description of behavior under loads it is used the relations for the increment of stresses with the corresponding deformations through the matrix of limiting state, obtained on the basis of the transformation of the certain yield function of the material. The new approach for structure analysis and corresponding algorithms of numerical calculation are developed. It is given an example of determining bearing capacity of reinforced concrete beam, where the results of the solution are compared with the known solutions of structural and solid mechanics. [ABSTRACT FROM AUTHOR]

The problems of propagation and diffraction of non-stationary waves in elastic bodies are of great theoretical and practical importance in such areas of science and technology as aircraft construction, shipbuilding, seismic exploration of minerals, seismic resistance of structures, and many others. The paper considers the problem of propagation of skew-symmetric nonstationary waves in an elastic spherical layer. To solve the problem, the integral Laplace transform with respect to dimensionless time and the method of incomplete separation of variables were used. In the space of images, the problem is reduced to an infinite system of linear algebraic equations, the solution of which is sought in the form of an infinite series in exponents, which makes it possible to obtain a solution to an infinite system without using the reduction method. Formulas are obtained for the components of the displacement vector and the stress tensor. The transition to the originals is carried out using the theory of residues. Numerical experiments were carried out, the results of which are presented in the form of graphs. The obtained results of the work can be used in the field of geophysics, seismology and design organizations in the construction of structures, as well as in the design of underground reservoirs. [ABSTRACT FROM AUTHOR]

Sustainability urges the construction industry to search for alternative but suitable materials. To evaluate the applicability of these materials, engineers should conduct tests and predictive models. Shear stress – strain behavior of soils and geo-materials is important in the analysis of slope stability of embankment. Dilative and contractive phases are encountered in sandy and non-plastic types of material. While constitutive models are commonly used to predict the behavior of these materials, these models require laborious parameter determination and complex predictive equations. In this paper, the shear strength behavior of dilative and contractive materials, specifically mine tailings, were simulated using Gaussian process regression (GPR) machine learning. Three types of mine tailings tested under the direct shear apparatus were considered. The model predictors included five vertical stresses (KPa), three initial relative densities (%), and the shear strain (%) while the responses were the shear stress (KPa) and the volumetric strain (%). Results show that the GPR models provide good prediction of the shear stress – strain and volume change curves of the three mine tailings both for dilative and contractive samples with 98-99% accuracy on independent experiment data. [ABSTRACT FROM AUTHOR]

Gear transmissions are widely used in modern machines due to the high efficiency, invariability of gear ratio, large power range and compactness of construction. The design process of such machine parts is rather complex since multiple factors such as geometrical, technological, exploitation and material features has an impact on the obtained results. In this paper, the influence of the parameters of the zero-backlash spur gear wheel on the stress distribution is presented with using finite element analysis performed in ABAQUS. The obtained results shows the importance of proper shaping of the geometrical features of the gear wheel. The methodology presented in this paper can be used to improve the design process of zero-backlash gear transmissions as well as to analyze the existing designs in order to verify its exploitation properties. Additionally, the presented research has a didactic purpose to highlight main risks and problems with using dynamic FEM analysis for analyzing gear transmissions. [ABSTRACT FROM AUTHOR]

To calculate analytical model of buildings and receive stress-strain state results, triangulation of structural elements is required. Great attention should be paid to reinforced concrete multi-span floor slabs at the joints with vertical elements. Due to unevenness and complexity in form, the finite element mesh of slab in such places can become more concentrated, which leads to an increase in stress values and inadequately elements design. To prevent such negative consequences and create an even mesh all over the slab, additional mesh generation in such places is required. To simplify such problem and reduce human costs, adjustment of finite element (FE) mesh can be obtained by means of visual programming. The purpose of this paper is to obtain and compare the results of finite element analysis (FEA) of reinforced concrete floor slab in residential building and to adjust generated mesh at the joints with vertical elements by means of visual programming in SAPFIR-3D. The scientific and practical importance of the work stands in the describing of the method of adjustment of FE mesh generation of floor slabs at the joints with vertical elements by means of visual programming. The results of the research are based on the results of calculation in programming complexes SAPFIR-3D and LIRA-SAPR, also analysis of literary sources and practical experience of the authors. The article revealed the possibility usage of visual programming to adjust FE mesh of floor slab with aim to simplify its shape at the joints with vertical structural elements. There is considered method and options for visual programming in the SAPFIR-3D. In this paper, results of the 8-storey skeleton reinforced concrete residential building with basement, have been analyzed and compared. The practical importance of the results of this paper lies in the presentation of the proposed method to adjust FE mesh of floor slab by means of visual programming. [ABSTRACT FROM AUTHOR]

Ensuring the stability of the railway track at the approaches to artificial structures is ensured by creating sections of variable stiffness in this zone, within which the stiffness of the track is leveled. The paper presents the results of studies on modeling the state of the structure of a section of variable stiffness (reinforced concrete boxes filled with crushed stone) when calculating the stress-strain state of bodies with anisotropic properties and their calculation-based determination. The inverse problem of forced frequency oscillations of a transversely inhomogeneous elastic layer of constant thickness is considered. By varying the values of the mechanical anisotropic characteristics of a structure with variable stiffness, it is possible to determine the confidence interval for the permissible values of frequency oscillations. Based on the mathematical solution of the engineering problem of deformation of the track superstructure under a moving dynamic load, curves of the vertical deflection of the rail were obtained for various parameters of the reinforcing structure. [ABSTRACT FROM AUTHOR]

Rocket motor nozzles have to withstand their extreme working loads including thermal loads. In this paper, thermal stress analyses on two different MX-450 motor rocket nozzle designs were performed to study their responses to the ignition thermal loads. The first nozzle design is of which had been used in the 2021 static-firing test while the second one is a newly modified nozzle design with an increased graphite thickness in the front part. The conducted simulations included the fluid-structure interaction method with thermal quantities as the transferred data between the solid region and the fluid region. The results show that the latest iteration of the nozzle has a difference in comparison to the first design in terms of the lowest minimum principal stress by 8.7 MPa. [ABSTRACT FROM AUTHOR]

The paper reports on Finite Element Analysis (FEA) and shape optimization of the automobile brake lever. Finite element analysis was carried out in the finite element tool. The first part of the research was a comparative study of Finite element analysis using real life data collected for polylactide (PLA) samples. The stress and deformations were analyzed on the Brake lever using ANSYS tool so as to compare and achieve safer design. Purpose of the Finite Element Analysis is to optimize the shape of the Brake lever in order to ensure adequate safety and ergonomics of use. The induced stress was well within maximum permissible limits for the material used during its operation. The obtained results have been validated using published data. [ABSTRACT FROM AUTHOR]

Contact stress between the contact parts may not be significant at the time of design in comparison to other parameters but it is very important to consider while designing the product. Contact stresses can be occurred between sphere and sphere, cylinder and cylinder, cylinder and sphere etc. In this paper presented the contact stress analysis for cutting tool of milling machine with various materials such as Al 7075-T6, Brass and Mild steel. The contact stress analysis was studied in simulation and observed the contact stress during the impact and shear stresses in each body. The contact force was calculated experimentally by using milling dynamo meter. [ABSTRACT FROM AUTHOR]

This paper contains brief overview of analysis of chassis in manufacturing of four-wheeler chassis. Analysis of chassis is important factor to make a chassis more durable, economical, and robust in all terrain. Ansys is the software used for the analysis and stimulation of the chassis design with various materials selection at various condition. Chassis of different material have different advantages in the same conditions. This study involves modelling of the chassis in CREO parametric and analysing total deformation, directional deformation, strain energy, equivalent stress and maximum principal stress with taking different materials in static structural module of ANSYS. By plotting the graphs selection of the material is easier from various materials and analysis the final result. [ABSTRACT FROM AUTHOR]

The next phase of industrialization in the world is use of 3D printing Technology. Various 3D Printing technologies are widely used from 1980s. 3D printers has classified based on its Print time, coordinate system and cost. 3D Printer is a machine which produce a complex design of any component by process layer by layer. Delta's printers are the parallel mechanisms where each of the motion is independent of each other. The arms which maintain orientation of the end effectors. Delta's printers are widely used because of its high speeds and accuracy with less inertia. This paper involves the analysis and simulation of faster and fixed bed printer called Delta 3D printer. First part of the paper is model is done in solid works. The model is imported into FEA software ANSYS 18.1 to calculate stresses and deformations of Delta 3D printer with different materials for base, rod and columns respectively. Next part is modal analysis also carried out to the natural frequencies at six nodes of the delta 3D printer for safe design. [ABSTRACT FROM AUTHOR]

This paper presents the failure analysis of the rocker arm, which experienced abrasive wear failure. History and chronology will be given to identify what factors triggered the disappearance. Visual examination and micro-hardness Vickers tests have been carried out to collect evidence to prove the hypothesis. The design evaluation in stress and fatigue characteristic conditions has been simulated using FEM-based software. All data have been analyzed and then assembled into one complete story to conclude. This paper presents a detailed fractographic and stress study to assess the causes of failure. [ABSTRACT FROM AUTHOR]

The cantilevered beam with piezoelectric layers is known for its mechanical vibration-to-electricity conversion. This process is known as the direct piezoelectric effect, where electricity generation is under applied mechanical stress. To investigate a physical and intuitive explanation for the power characteristics of a strongly electromechanical coupled field, understanding the coupling process of the force and electric field in the cantilevered beam is of paramount importance. This paper presents the characterisation of the electric power output of the piezoelectric cantilevered beam. For that purpose, the modelling and simulation of piezoelectric cantilevers beam have been performed using the finite element method. The simulation results show that the deformation of the cantilevered beam influences the frequency attained by the model. The finding of these results may be used as a reference in the development of piezoelectric energy harvesters devices. [ABSTRACT FROM AUTHOR]

The fracture toughness of materials is a fundamental parameter in assessing the structural integrity of crack-containing structures. Issues relating to economic demands in the availability of materials for testing and imposing strict rules to structures that exhibit enhanced toughness due to geometries and loading conditions caused the need to consider the application of fracture toughness measurement with small-scale specimens. The current small-scale testing and fracture toughness characterization still need to fully fulfil the fracture toughness data transferability from the laboratory test specimens to real structures influenced by unavoidable defects. This paper outlines the conventional elastoplastic fracture toughness approaches and how they apply to small-scale specimen fracture toughness testing. Recent techniques to characterize three-dimensional elastoplastic stress-strain fields around the crack tip were highlighted, as an extension to the current two-parameter fracture toughness assessment was proposed. Explicit expressions were given to develop an analytical formulation for small-scale fracture toughness measurement and characterization. [ABSTRACT FROM AUTHOR]

A carport is an integral part of any family home that does not have its own garage. It is an ideal solution that is both modern and practical. The role of such shelters is to secure the vehicle mainly from the external weather and at the same time to ensure their own long life and minimal maintenance. Therefore, for such requirements, there are not only standard standardized shelters, but it is also possible to design atypical shelters that take into account the specific requirements of the customer. In this paper, we therefore focused on the current state of production of carports. The aim was to create a structural shelter for two cars. Another condition of the customer was that the width of the entrance to the shelter was 5.5 m. The resulting design that represented our solution was designed based on numerical analysis and the identification of a number of design concepts that were often oversized or had incorrect shape geometry. For some existing variants on the market, we have confirmed the presence of large voltage concentrators occurring in the critical most stressed places of the shelter. To avoid this problem, it was first necessary to identify which construction materials are often used for these purposes, and then we specified their mechanical properties. After a suitable choice of construction material for the shelter, we were able to proceed to the specification of possible external loads affecting the stability and safety of the proposed shelter. By analyzing the standards and known relationships for the calculation of structural safety, knowledge was obtained whether the proposed structure is sufficiently resistant to the proposed external static load. The results of static analyzes, analysis of loss of structural stability, strength control of anchoring segments and the results of stress-strain numerical analysis contributed to the design of the final design solution for the construction of the shelter according to the customer's requirements. [ABSTRACT FROM AUTHOR]

The goal of design optimization is to find a technically feasible design of machinery, respectively its parts as the best solution of all possible. The optimal result is quantified through the extreme value of a suitably selected objective function while adhering to the constraint conditions defined by the designer. The objective function is often presented as the weight of the optimized design, resp. its volume. We also encounter tasks where the objective function is price, in which case the functions defined in the restrictive conditions are also affected. Depending on the type of engineering problem, the objective function can also be the value of maximum deformation or stress. In the case of dynamics, this can be prescribed the eigenvalues of the dynamic system, etc. In the paper, the authors present selected methods of discrete optimization in terms of the mass minimization of truss and beam structures subject to the limiting condition of limited fatigue life. The load of the structure is modelled by the forces in the given nodes and directions and the number of operating cycles with the appropriate load period. The calculation of fatigue damage accumulation was performed by applying the Corten-Dolan hypothesis. The whole calculation process was realized in MATLAB using a files compiled by the authors. [ABSTRACT FROM AUTHOR]

The paper investigates the influence of steel fibers on the bearing capacity, deformability and fracture resistance of the supporting sections of bending elements. Beams of rectangular cross-section of two series-reinforced concrete beams of ordinary concrete and beams of combined reinforcement using steel fibers were considered. To make the specimens of the second series, steel anchored fibers were evenly added to the concrete, the total volume of which was 1% of the mixture volume. A special force bench was assembled to test the beams. During the tests, the load applied to the beams, deflections and deformations of individual concrete fibers were recorded. The load was applied in steps of 0.05 of the destructive load, the value of which was determined in the process of preliminary test loads. The carried out researches showed that the bearing capacity of the beams of combined reinforcement was practically by 50% higher than that of the conventional reinforced concrete beams. The breaking load in combined reinforcement beams is 162kN, and in conventional reinforced concrete beams 112kN. The deflections in steel-fibercrete beams by the time of failure are 1.4 times less than in reinforced concrete beams. The relative tensile deformations of concrete fibers in the shear span at the moment of failure are 3 times higher than those in the pure bending zone. [ABSTRACT FROM AUTHOR]

A genetic algorithm is proposed for finding the optimal distribution of material along the beam length under constraints on a strength and on the maximum value of beam deflection. The paper considers a beam that maintains the section proportions along the entire beam length. I.e. the geometric parameters of the beam cross section are proportional, for example, to its height, which varies along the beam length. The beam is statically determinate, and the load can be arbitrary, including asymmetric and multidirectional. The points (or point) at which the beam deflections are maximal are not known a priori and are being found in the problem solution process. A linear formulation of the problem is considered. The optimization criterion is the mass of the beam. To find beam deflections, i.e. to solve the differential equation for the bending of a beam of variable cross section, the finite difference method is used. The design problem is reduced to the problem of beam height values finding in a system of nodal points. In this case, the desired solution must satisfy the system of constraints on the shift of nodal points and constraints on the maximum stress values in the beam. Shift and stress constraints in each node are considered separately and independently; therefore, the proposed technique allows solving a wide range of problems. An objective function is proposed, this one is the sum of the beam mass and possible penalties for exceeding the maximum deflection specified in the condition and the maximum allowable stress values. During the genetic algorithm work, the beam thicknesses (from present sets) are selected only that ensure the reach of the objective function minimum. A model problem is solved, and it is shown that the proposed algorithm allows one to effectively solve the optimal beams design problems in the presence of constraints on the maximum deflection. The proposed approach can be developed for several design cases, for statically indeterminate constructions, etc. [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]

Application of Oxy fuel combustion (nitrogen free combustion) into a diesel combustion IC engine is resulting in a huge variation in in-cylinder pressure and temperature, compared to the conventional air combustion. The variation is observed in both rate of change of variables versus Crank Angle Degree and the peak values, impacting the thermomechanical behaviour of piston. This paper presents a study and comparison of oxy fuel combustion with conventional air combustion on thermomechanical stress and fatigue life analysis of piston. The temperature and pressure loads on the piston are extracted using an experimentally validated computational fluid dynamics model, at the most severe working state, which is at peak power operating condition. The analysis is based on the stress life approach using a finite element model, considering temperature dependent material properties of piston coupled with thermal stress field and thermomechanical stress field. The thermomechanical results indicate that the Oxy fuel combustion is the most favourable environment for piston, as the minimum fatigue life is 15.5 times higher and the equivalent stresses, maximum principal stresses are 11% lower than the conventional air combustion. [ABSTRACT FROM AUTHOR]

The paper is devoted to the analysis of the parameters of acoustic emission signals recorded during deformation of the D16AT aluminum alloy used in aircraft construction. The previously developed technique for separating AE signals by source types made it possible to distinguish an additional stage at the stage of strain hardening of the deformation diagram σ(ε), which is not detected by other methods at the macro-and meso-levels of deformation. The stage is characterized by the registration of AE signals with certain values of the parameters of the two-parameter distribution E-Kf, corresponding to radiation from dislocation-type sources. The high activity of radiation of this type AE signals is associated with the formation of dislocation loops on the particles of the secondary phase, precipitated during the aging of the D16AT alloy. [ABSTRACT FROM AUTHOR]

Human life in the modern scenario has become quite taxing; mental health issues are on the rise. Our medical science may have progressed well enough to furnish physical health excellency in the general populace (of course, in relative terms), but mental health is still taboo. This is especially so in many of the non-first-world countries, where forthcoming mental health issues and asking for help can lead to anything from public ridicule to social ostracism. In such a scenario, it is of paramount importance that someone comes up with a more private approach to mental health care and well-being. In this paper, the authors discuss how the effects of stress can be monitored using a different implementation of k-NN (k-Nearest Neighbors). With this, using the Manhattan distance metric we were able to achieve 99.84% accuracy, and even after the application of PCA, we achieved 93.97% accuracy. [ABSTRACT FROM AUTHOR]

One of the most important techniques of the convective process is by means of fins, which have a significant impact in the manufacture of cooling and heat transfer transformers used in many of the devices used. These fins have the ability to increase the area of heat transfer as they work on turbulence of the fluid used and thus increase the process heat transfer. In this research paper, the presence and distribution of fins in a mini-channel and irrigation system were studied to improve heat transfer in it. The effect of this disturbance on the deformation and stress affecting the fins was studied. The results showed an improvement in heat transfer in the use of distributed fins. [ABSTRACT FROM AUTHOR]

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 present paper is devoted to the analysis of experimental data on the parameters of plastic strain localization within the model of autowave plasticity using specimens of commercially pure polycrystalline aluminum. This material lacks the stage of linear strain hardening: the deformation process occurs with parabolic strain hardening by the law σ~εn at the exponent n=0.5. The analysis of displacement fields of the surface points of a specimen deformed in the temperature range 170–350 K reveals perfect matching of the parabolic strain hardening law working in a region to the plasticity localization pattern in it. It is shown that temperature affects the length of the strain localization autowave at the stage of parabolic strain hardening with the exponent n=0.5. [ABSTRACT FROM AUTHOR]

This paper presents the results of a numerical simulation of the interaction of the cylindrical steel projectiles with orthotropic barriers made of organic plactic. Problems are solved numerically, by the finite element method, in a three-dimensional formulation within the framework of the phenomenological approach to solid mechanics using the original EFES software package. The behavior of the steel projectile material is described by an elastic model. The behavior of an anisotropic material is represented by the elastic-brittle model. The effect of failure criteria on the stress-strain state of an anisotropic barrier is compared. [ABSTRACT FROM AUTHOR]

In this paper, the model of elastic-plastic media in Drucker – Prager form was adapted for analysis of the stress state of the lithosphere. The Cratonic Jelly Sandwich model was used to define the cohesion and coefficient of internal friction dependences on depth. To test this adaptation, the mechanical behavior of deep geological structures was numerically analyzed. To create the computer structures of the researched region, the geological data of the "Shpat– 1983" profile was used. It is shown that plastic strain begins in the weak layers of the Earth's crust and upper mantle and progresses to the strong layers of the Earth's crust in the form of bands. [ABSTRACT FROM AUTHOR]

The sensitive behaviour of two dimensional (2D) materials owing to its unique structural, electronic and mechanical properties make them promising materials for their future applications in the field of medicine and electronics. The evolution of some eminent 2D nanomaterials starting with graphene to silicene to transition metal Di chalcogen have been explored with respect to electrical and mechanical properties. In spite of having extraordinary properties of graphene like high mobility of electron and hole, good stability, its zero-band gap impedes its applicability in the nano science field which is further eradicated by the introduction of new graphene like 2D sheet, silicene. Silicene has non zero band gap with buckled structure can further be altered with the help of functionalization and mechanical strain. In terms of commercialization of 2D materials, transition metal Di chalcogen proved to be the nice choice among the material in relative of graphene and silicone. The tuning of band gap of TMDC's with mechanical strain have been illustrated in the paper with the explanation of optoelectronics devices. [ABSTRACT FROM AUTHOR]

Excavator is a manually operated heavy vehicle used in various processes like construction, digging, lifting heavy loads, and mining. The bucket of the excavator is the one that is used for excavating tasks. Changes in factor of safety of the bucket, deformation, and stress acting on the excavator bucket are discussed in this paper. A three-dimensional model of the bucket is developed and the model is imported to ANSYS workbench 22 R1 software. Data of the materials on which the analysis is to be done are added. The materials used for analysis in this project are AISI 4140, AISI 4150, and AISI 4340. After adding materials, the model meshes, after the meshing is complete fixed supports and the impact on teeth is added followed by obtaining the values of total deformation, equivalent elastic strain, and equivalent stress. Once the result is obtained, the same procedure is followed for different loads, a different number of teeth, and different materials. After obtaining the solution for various combinations of load, teeth, and materials, the solution is graphically analyzed to understand how the stress, deformation, and factor of safety vary with change in impact and how the number of teeth plays a major role in bucket design. [ABSTRACT FROM AUTHOR]

The paper studies pure bending of a strip (beam) containing through crack which is perpendicular to its axis and asymmetrical about the one. One of the crack tips is in the compressive stress zone and crack faces are in smooth contact near it. The other one is in the tensile stress zone and there is a striplike plastic zone on the crack prolongation line near this tip. The solution is reduced to linear conjunction problems using methods of complex analysis and complex potentials. The length of crack faces contact zone, the length of crack tip plastic zone and crack tip opening displacement are evaluated. Their analytical solution is found. The system of transcendental equations for calculating the length of crack tip plastic zone and parameter, that characterized the length of crack closure zone are established. Formula for calculating the crack tip opening in noncontact tip and dependencies for the stress tensor components on the line, where the crack located are wrote. Numerical analysis of crack tip opening in her noncontacting tip and the length of crack tip plastic zone from reduced external load and location of crack center relative to the axis of the strip (beam) is done. The parameter, that characterized the length of crack closure zone doesn't depend from external load is find numerically and a simple formula for its determination is given. The critical value of the bending moment of fracture of the beam (strip) with the contact crack is estimated based on the δк-model of fracture of crack bodies. [ABSTRACT FROM AUTHOR]

The article deals with the issue of finding the optimal geometry of a thin-walled retaining wall. The ideology of the approach is that the curvilinear retaining wall and the backfill soil are considered as a single system in which the shape of the retaining wall determines the magnitude and nature of the external load distribution. The essence of the approach is that the retaining wall is divided into a finite number of linear segments. As a result of a number of analytical transformations, dependencies between the attributes of the stress-strain state of the structure and the system of segments slope angles are constructed. The task is reduced to finding such a combination of slope angles of segments, which will determine the minimum of the accepted rationalization criterion. As part of the operation of the BEO method, the configuration of the retaining wall was found, which will minimize the potential strain energy of the system. To simplify the use of the study results, the rational form of the retaining wall surface is approximated by a 4th degree equation. The paper presents the values of the coefficients of this equation depending on the initial calculation data. Based on the results obtained, the design of a rational retaining wall is proposed, and the technological process of its construction is described. [ABSTRACT FROM AUTHOR]

The basic function of the gas turbine blades is to rotate the shaft connected to the generator motor. In electricity generation station, because the materials used in manufacturing must resist harsh working conditions, gas turbine blades are subject to high vibration, pressure and temperature. In this paper, the maximum pressure and deformation are caused by the effect of centrifugal force on the gas turbine blades. And to determine the natural frequencies of vibration, which are caused by the rotation speed about 3000 r.p.m under high-temperature conditions. The finite element method (FEM) was used to determine the natural frequency of turbine blade material (GTD-111) applied in the South Baghdad Power Station in Iraq, Baghdad. This paper deals with the structural analysis of gas turbine blades. Analysis was performed to find out the mechanical stresses and radial elongation to which the gas turbine rotor blade is subjected. A solid turbine blade model is constructed using the SOLIDWORKS2018 software. The turbine blade is analyzed for its structural performance due to the loading conditions using ANSYS 19 software to study the stress variation on the GTD-111 alloy gas turbine blades. The results shows that under static load and the stress and strain on the blade, the amplitude of the blade vibration will change at the higher frequencies of 581.42 Hz and 935.84 Hz because the root of the blade is placed on the disk-like cantilever (girder fixed at only one end). [ABSTRACT FROM AUTHOR]

Engineers are particularly interested in brick due to the fact that they contain a maximum amount of space with a minimum amount of surface area, they have shown to be very inexpensive in terms of constructional materials consumption The first braced dome was the ribbed dome. As the name implies, it is made up of a sequence of similar meridional solid girders or trusses, which are linked at the crown by an elastic band or a compression band. In this paper a comparison between the strains and deformations of a brick dome and that of a ribbed dome. With the help of STAAD Pro V8i, finite element models of these domes were built and analyzed. For the bricks, shell elements were used, while steel sections were used for the ribs and rings. There was a pressure on the entire surface of the dome from the loads. Brick failure criteria were determined by analyzing stresses and deflections of the dome. Various distributions of ribs and rings were tested in order to determine the optimal angle of rib distribution and ring spacing. The stresses and deformations of a brick dome and a ribbed dome were compared in this paper. STAAD Pro V8i software was used to create and analyze finite element models of these domes. Shell elements were used to simulate bricks, while steel sections were used to simulate ribs and rings. Loads were applied as a pressure on the entire dome's surface. The stresses and deflections of the dome were investigated in order to determine the failure criteria in bricks. In order to identify the optimal angle of the steel rib distribution and the space between rings, ribbed domes with various steel rib and ring distributions were tested. In order to compare the brick dome with ribbed dome, new analysis of the same dimensions of brick dome were done. Standards steel section was used for ribs and rings, 240 mm thickness of brick fill the area between ribs and rings. The behavior of this dome under the same load was study. The analysis showed, that dome with steel ribs of angle in plan theta (15 degree) was successful to resist the loads and the tensile stresses of brick were less than 0.20 N/mm2 (maximum tensile strength of used brick), when the angle in plane theta increase to 22.5 and 30 degrees, the hoop tensile stresses in brick exceeds the tensile strength limit. So that the meridional cracks may be appear at the springing zone of dome. While crushing failure did not occur, where the compressive stresses in all models were lower as compared with brick allowable compressive strength (0.80 N/mm2). [ABSTRACT FROM AUTHOR]

The paper focuses on replacing the front suspension system of a three wheeler vehicles that are presently seen making use of torsion bar suspension in front suspension. The torsion bar suspension system was earlier used in the early 1990s and late 2000s until then the helical coil suspension came into existence for a lot many vehicles being successfully replaced as it provided better feasibility and maintenance than those seen in torsion bar suspension system. Here, in this project currently a vehicle with payload capacity of 4500N, three wheeler mini-door is taking into application. It has ground clearance of 250mm from the ground level. It was verified both mathematically and analytically which of the designs off different materials pave excellent properties close enough to replace Torsion Bar Suspension. CAD model of the helical spring was done in CATIA, followed by ANSYS Simulation with proper conclusion. This project focuses on designing a helical coil for front suspension for those three wheeler vehicles which are still using Torsion Bar Front Suspension in today's condition as a replacement. The spring was designed by following the methods given in V.B. Bhandari that can withstand the vehicle weight along with payload capacity of 990Kg, that the vehicle can sustain, using different material compositions like 54SiCr6, 50CrV4, ASTM A229 apart from those used in torsion bar suspension, at a lower price and with an objective to provide better facilities that torsion bar cannot provide. Equivalent stress, shear stress analysis have been carried out using ANSYS on the designs proposed by allowing a deformation of 166 mm for set stiffness 25KN/mm as per reference papers and previous research work, and checked out of the three which spring provide the optimum results from the different materials and were selected accordingly. [ABSTRACT FROM AUTHOR]

The paper provides a detailed analysis of the work under load structures of clamp scaffolds and systematizes the features of considering loads and impacts when performing strength calculations. The article analyzes the stress-strain state of free-standing forests. An algorithm for calculating free-standing forests is proposed, considering the features of structural schemes of blocks that are not specified in the normative literature. Based on the results of the analysis of data from a series of numerical experiments, constructive measures are proposed to ensure the load-bearing capacity, rigidity and stability against overturning of spatial blocks of free-standing forests, which will allow installing blocks with a height-to-size ratio exceeding 3,5:1 in open areas (outside buildings and structures) without attachment to existing structures. Considering the eccentric connection of scaffolding elements leads to a complex deformation of columns (oblique eccentric compression), i.e. to increase in the resulting bending moments up to 100%. Using of diaphragms in the design of free-standing clamp scaffolds blocks reduces the displacements of the block nodes by up to 16% in comparison with blocks without a diaphragm Another feature of scaffolds is that they are used for not only classic buildings and structures and for the maintenance and repair of various space stations and aircrafts. [ABSTRACT FROM AUTHOR]

A thin quasicrystal layer is lying on an isotropic base matrix with rather large thickness. The interface crack between these dissimilar materials is considered and the bilayered structure is under a heat flux load. Due to the very thin quasicrystal layer, size effects cannot be ignored and utilization of the gradient theory is a challenge for proper description. Decagonal quasicrystal material properties are considered for this layer. The uncoupled thermoelasticity is considered here, where the thermal transport is analyzed independently on mechanical fields. Classical heat conduction seems to be inadequate for thermal transport in nano-sized structures. A novel gradient theory is applied here, where in contrast to the Fourier law, the heat flux is affected not only by a temperature gradient but also by the 2nd order derivative of temperature. In the gradient elasticity of quasicrystals the constitutive equations for phonon and phason stresses contain both phonon and phason strains, however, only the phonon strain gradients and the conjugated higher-order stresses are taken into account. The finite element method (FEM) is developed for boundary-value problems where governing equations have higher-order derivatives than in classical theories. Therefore, the standard C° continuous finite elements are insufficient. A mixed FEM is developed for boundary value problems of both the gradient theory of heat conduction and elasticity. In numerical examples various microstructural length-scale parameters and the thickness of the quasicrystal layer are considered. The influence of these parameters on the crack opening displacement is investigated in the paper. [ABSTRACT FROM AUTHOR]

The combination of plastic and creep analysis formulation are developed in this paper. The boundary element method and the finite element method are applied in plates in order to do the numerical analysis. This new approach is developed to combine the constitutive equation for time hardening creep and the constitutive equation for plasticity, which is based on the von Mises criterion and the Prandtl-Reuss flow. The implementation of creep strain in the formulation is achieved through domain integrals. The creep phenomenon takes place in the domain which is discretized into quadratic quadrilateral continuous and discontinuous cells. The creep analysis is applied to metals with a power law creep for the secondary creep stage. Results obtained for some models studied are compared to those published in the literature. The uncertainties in both geometric and mechanical properties are considered in order to obtain the structural response. The approach is illustrated in a plate subjected to incremental load, results show that there are high probabilities of exceeding the damage states, w, equal to 0.3, 0.6, 1.2, 1.8 and 2.4 while for values of w equal to 3.0, 3.6, 4.2, 4.8, 5.4 and 6.0 these probabilities are low. The obtained results are in good agreement and evinced that the Boundary Element Method could be a suitable tool to deal with combined nonlinear problems. [ABSTRACT FROM AUTHOR]

The paper examines the effect of cylinder length on the rocket motor tube's safety factor and weight ratio using a thin-walled cylinder. The outer diameter, wall thickness, cap thickness, and cylinder fillet radius were 550, 8, 50, and 100 mm, respectively. The length of the cylinder was varied 3, 3.5, 4, 4.5, and 5 meters. The internal pressure used is fixed, which is 12 MPa. The materials used are Aluminium 7068-T6 and Aluminium 7034-T6. Stress analysis using the finite element method with Ansys Workbench software to select the optimal length of the rocket motor tube in terms of the safety factors and tube weight ratio. The simulation results show that the longer the rocket tube, the lower the safety factor ratio and the weight of the rocket tube both when using Al 7068-T6 and Al 7034-T6 materials. The highest ratio value is when the rocket tube has a length of 3 meters using Al 7034-T6 material. [ABSTRACT FROM AUTHOR]

A premium storage tank has been built in an oil refinery complex. Once the tank is completed then water is pumped into it and tested by loading it with water until the level of HHLL (High-High-Liquid Level) and kept the water for a couple of days as a functional test. Measurement and observation then were carried out after having pumped out the water and the tank become empty. The measurement was focused on the diameter and observation was to the foundation of the tank. The tank was found to be deformed and showed deviation from a perfect circle. On the other hand, there were also some settlements of foundation detected near the tank's bottom edges. Due to this fact, this paper presents the results of the finite element analysis of the storage tank structure using the finite element method after deformed by a functional test. The analysis was carried out to discover the effect of stress and deformation on changes in tank shape and settlement of the foundation (tank base). Furthermore, the factor of safety was calculated by comparing the properties of the material with the maximum stress that occurs in the structure. After results obtained from the 3 (three) run variation, it can be concluded that the three maximum stress values produce a factor of safety value of more than 1.00 (one), so that the stress that occurs does not exceed the required allowable stress and the tank can operate safely. [ABSTRACT FROM AUTHOR]