In this paper, there are issues related to the choice of elemental modelling of thin-walled beams with various types of fillers for quasi-static bending loading, which causes washing of beams and filler, as applied to the optimal design. The objects of research are thin-walled beams made of aluminium AMG6 contains fillers made of aluminium foam, epoxy resin and composite (consisting of Poraver balls and epoxy resin). One of the best fillers for solving the problems of crashworthiness is requiring expensive technological equipment for filling. Epoxy resin is a fragile material, but inexpensive, affordable and technologically “convenient”. In addition to the influence of the filler on the mechanical properties of beams, the effects of the constrained behaviour of the material of the filler under the bending loading of beams are investigated with Zwick Z100 (for hollow thin-walled beams made of aluminium and the same beams with fillers).The paper presents the results of numerical calculations and the results of the experiment (the error of calculations does not exceed 8%).The most rational is the ratio between the indicators of energy intensity - the mass is aluminium-foam (with an increase in the mass of the sample by 2,1 times the mechanical properties reach 10 of times). The remaining fillers give significantly worse results for the same parameters. To assess the effectiveness of the use and creation materials for the refinement of the cabins and car bodies according to the crashworthiness.

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BACKGROUND: At the present time, new technologies of joints adhesive joints are used more and more widely along with spot welding in domestic and foreign vehicles. Study of the joint strength and the influence of deformation rate and the adhesive layer thickness under impact loading on the parameters of the joint in a vehicle is a relevant technical task. AIMS: Study of the influence of deformation rate and the adhesive layer thickness on the adhesive joint parameters (strength, deformation, etc.) under impact loading as well as evaluation of the efficiency of the proposed modified calibration method for the adhesive layer model on the example of tubular structure, which is often used in the strength elements of a vehicle. METHODS: Experimental studies were carried out with impact loading at the speed of 6.66 m/s (the axial im-pact) and 6.87 m/s (the side impact) with the mass of 22.3 kg. Simulation of operating conditions was performed in the LS-Dyna software that made possible to study the stress-strain states (SSS) of adhesive-bonded tubular structures and to estimate the simulation error. RESULTS: Based on experimental and calculated results, the length of the adhesive layer failure under the impact loading in the steel structures bonded with the Henkel EP 5055 adhesive is shorter in the joints with the 0.5 mm thick adhesive layer than in the joints with the 1 mm thick adhesive layer. The total deformation of the bonded structure at the side impact loading for the 1 mm thick adhesive layer is less than for the 0.5 mm thick layer, as the adhesive layer absorbs some of the energy. For the axial impact loading, the differences are insignificant. Errors of adhesive joint simulation under impact loading have been reduced significantly (by 15%) with using the proposed modified method of calibrating the adhesive layer properties considering the influence of the deformation rate and the adhesive layer thickness in the finite element model. CONCLUSIONS: The practical value of the study lies in the proposed modified model, considering the influence of the deformation rate and the adhesive layer thickness under impact loading on the joint parameters and making possible to improve simulation accuracy, as well as in recommendations for the best value of adhesive joint properties in adhesive-bonded vehicle structures.

Introduction (problem statement and relevance). Ensuring safety of road vehicles is a relevant problem. It is particularly applicable to the road construction machinery. The paper presents an algorithm that allows obtaining the most accurate results of calculations according to the procedure described in GOST R ISO 3471 (ROPS): Earth-moving machinery. Roll-over protective structures. Technical requirements and laboratory tests.The purpose of the study is to investigate the stress-strain behavior (SSB) of a structure of a utility platform taking into account residual stresses, strains and relaxation of the structure under multiple loads according to the roll-over safety requirements for earth-moving machinery.Methodology and research methods. The paper presents a skid-steer loader cabin model created in a fi nite element analysis program to perform the strength calculations. The comparative assessment was performed based on the results of a full-scale experiment carried out on a real structure and of virtual simulations. The research object is a skid-steer loader cabin. The research subject is the design methods for vehicle load-bearing structures and their use taking into account operating conditions.Scientific novelty and results. An algorithm has been created which takes into account residual stresses, strains and relaxation of the structure for further loading and allowing reduction of a displacement calculation error for a utility platform from 84.5 to 4.5%. The internal energy reached under vertical load is 426% higher, while for the longitudinal load case it is 14.6% higher, than for the option not taking into account residual stresses and strains.Practical signifi cance. The proposed algorithm allows considering the requirements of GOST R ISO 3471 regarding prevention of structure readjustment or repair between loadings, which is an actual operating mode.

This paper considered the main problems of finding the optimal parameters of a truck cabin based on parametric and topological optimization in order to meet the requirements for passive safety according to international rules and obtain its minimum mass. The article presents the developed rational finite element models (FEM) of the cabin and the pendulum for optimization problems, allowing to obtain results with acceptable accuracy and minimal solution time when using the LS-OPT and LS-TaSC programs with the LS-DYNA solver. Steel lining and foam aluminum filler are used as cabin reinforcement elements. To solve the problem and more fully assess the effect of the parameters, several options for cabin refinement were considered. Topological optimization was carried out with the aim of obtaining a picture of the best distribution of the filler along the cabin frame. Parametric optimization was carried out by selection of the properties of the filler (aluminum foam) and the thickness of the structural elements of the cabin. In addition to optimization, the sensitivity of the design to the variation of variable parameters was investigated in order to identify the degree of influence on the optimization result. Since the duration of the solution is very high (up to several days on available computers), an approach was developed based on the studies that were carried out, which at various stages reduced the number of variables and, thus, reduced the solution time. As a result, it was ensured that the requirements for passive safety were satisfied (these requirements were not met before optimization) with optimal mass distribution as a result of the combined use of linings and filler. The increase in cabin weight was 20%. The use of linings only allowed to meet the rules for passive safety, but gave an even greater increase in the weight of the cabin.