Balsa wood is a natural cellular material with an excellent resistance-toweight ratio that is ideal for manufacturing the core of sandwich structures. In this study, sandwich specimens with a carbon-fiberreinforced polymer (CFRP) skin and a balsa wood core were tested with static and dynamic loading. Three-point flexural tests in static regime determined the mechanical characteristics of the CFRP-balsa specimens that were needed for subsequent fatigue strength tests. Also, experimental research was performed on the Charpy impact response of the CFRP-balsa sandwich specimens. This study implemented an accelerated fatigue testing method to identify and predict the mean fatigue life of the CFRP-balsa sandwich specimens subjected to cyclic fatigue via three-point flexural tests. Using the accelerated fatigue and the three-point flexural testing methodology on the CFRP-balsa sandwich specimens, the testing period was reduced by 11.9 times, and thus the material costs necessary for the tests were also reduced. Also, the breaking surfaces were analysed to reveal the failure modes of CFRP-balsa specimens subjected to static and fatigue tests at threepoint flexural and at impact tests.

This paper presents an experimental investigation on the abrasive waterjet machining (AWJM) of Hardox steels. A full factorial plan was designed and carried out to determine how the traverse speed, the material thickness, and the material type influence the surface roughness. Two materials were machined during the experiments: Hardox 450 and Hardox 500. The experimental data were analysed using statistical methods, and a mathematical model was obtained. Additional experiments were made to validate the model. The results proved that the analysis is accurate and the mathematical model will be a useful tool in industrial environments for process planning when abrasive waterjet machining is used for the considered material.

In this paper, we present a calculation methodology of the testing duration of the products' reliability, using the Weibull distribution, which allows the estimation of the mean duration of a censored and/or complete test, as well as of the confidence intervals for this duration. By using these values we can improve the adequate planning and allocation of material and human resources for the specific testing activities. The proposed methodology and the results' accuracy were verified using the Monte Carlo data simulation method.

The research carried out within this paper addresses the issue of impact analysis with a spherical ball of an automobile fender, following two directions: the finite element method modeling of named part and situation, and experimental validation of the study mentioned beforehand. The part itself - car fender - is represented by a thermoset composite panel armed with Kevlar-Carbon fibers, while the analyzed situation is depicted as a Charpy/Izod test with a spherical ball on the specified component. The evaluation of named inquiry is performed in a virtual environment by means of FEA and verified accordingly within laboratory testing.

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