Taking into consideration the additional weight of a vehicle, today’s requirements can only be met using new materials and designs. The application of metal foam is one of the most promising methods of enhancing the impact energy absorption ability of the crumple zone. The energy-absorbing capacity of thin-walled structures filled with metal foams during compression can be notably improved, which results in lower loading on the passengers. The main goal of our research is to develop a new design that is suited to absorb more impact energy while taking into consideration weight optimization. The authors wanted to unveil the effect of the inhomogeneous filler material in these thin-walled structures. Therefore, the present study investigates the compression test of two metal foams of different densities, in different ways. In the first section, the foams were compressed independently from each other by a recording of a stress–strain diagram. After the single compression, the foams were loaded together, first in parallel, and subsequently in a serial scheme. The study aimed to reveal the effect of the parallel and serial compression scheme focusing on the sum of impact energy absorption.

Many processing companies use some grades of steel for cold forming. Due to ageing, the formability of unalloyed mild steel sheets deteriorates over time; their formability is not uniform, and surface defects appear, which in many practical applications leads to scrap. This can be particularly important for processing companies when selecting machine settings, as there may be differences in the properties of materials from different manufacturers and the properties of materials of different ages from the same manufacturer. We investigated the ageing behaviour of DC01 steel grade by testing many samples from the third day after production up to one year. Various methods were used to detect ageing, such as tensile tests at different test speeds and supplemented with a digital image correlation (DIC) system, thermo-electric power measurement, deep drawing cup tests, and Nakajima tests. We showed that a reinterpretation of the definition of ageing is necessary. Standard tensile testing can no longer detect the ageing tendency of steels manufactured using the latest technology. However, when supplemented with DIC, these tests show ageing with high sensitivity. Among the used methods the applicability of this technique in industrial material testinglaboratories is the most recommended.

One of the most critical issues during polymer finite element simulations is the selection of the proper material models. The widely used and accepted multilinear material models require load case-specific material tests, which are time and cost demanding. Data for these characteristics must be acquired by standardized measurements. On the other hand, the parameters required to create a linear elastic material model in most cases are easy to obtain, and the establishment of the model is a shorter process. This research is aimed to provide information to engineers about the possibility of modeling the nonlinear elastic materials by using linear elastic material models and about the limits of such models. To create the most accurate material models, laboratory measurements were performed on polyamide (PA6) material, which is a widely used raw material in the industry. Test specimens were manufactured to obtain material constants according to the ISO 527-2 standard, and for validating the effectiveness of the applied material models, three different tensile specimens were created, which were tested under quasi-static loading in the elastic region. A comprehensive finite element investigation was performed, and the numerical results were then compared to laboratory measurements using the GOM Aramis digital image correlation (DIC) system. By comparing the optically measured strain data to the numerical results, it was determined that the nonlinear elastic materials can be modeled using linear elastic models in a well identifiable strain range with sufficient accuracy.