Methods to predict the fracture of thin carbon fibre-reinforced polymers (CFRPs) under load are of great interest in the automotive industry. The manufacturing of composites involves a high risk of defect occurrence, and the identification of those that lead to failure increases the functional reliability and decreases costs. The performance of CFRPs can be significantly reduced in assembled structures containing stress concentrators. This paper presents a hybrid experimental–numerical method based on the Tsai–Hill criterion for behavior of thin CFRPs at complex loadings that can emphasize the threshold of stress by tracing the σ-τ envelope. Modified butterfly samples were made for shearing, traction, or shearing-with-traction tests in the weakened section by changing the angle of force application α. ANSYS simulations were used to determine the zones of maximum stress concentration. For thin CFRP samples tested with stacking sequences [0]₈ and [(45/0)₂]_s, the main mechanical characteristics have been determined using a Dynamic Mechanical Analyzer (DMA) and ultrasound tests. A modified Arcan device (AD) was used to generate data in a biaxial stress state, leading to the characterization of the material as a whole. The generated failure envelope allows for the prediction of failure for other combinations of normal and shear stress, depending on the thickness of the laminations, the stacking order, the pretension of the fasteners, and the method used to produce the laminations. The experimental data using AD and the application of the Tsai–Hill criterion serve to the increase the safety of CFRP components.

Composites occupy an important place in high-end industries due to their superior characteristics compared to traditional materials or individual constituent materials. The work focuses on the FEA analysis of composite materials with CFRP carbon fibers with polymer matrix subjected to tensile and shear loads, an important subject of study in the field of engineering. The analysis using the finite element method is a real help by simulating the materials in different conditions. Due to their advanced properties, composite materials can be tested and optimized before being used in production. This can reduce the need to make prototypes and testing multiple times. The aim is to increase productivity and eliminate excess waste, an important process that is the basis of all industries today. Modified butterfly-type specimens were used in these research studies to be tested on the Arcan device. The simulation conditions were similar to a tensile and shear test conducted in the laboratory, considering a material without cracks or other impurities in its structure and utilizing mechanical properties provided by software Ansys for unidirectional carbon fiber and epoxy-reinforced matrix.

This paper focuses on the deposition and characterization of tungsten carbide (WC) hard thin films using the plasma jet deposition technique, with special emphasis on their hydroabrasive wear behavior. Tungsten carbide coatings are recognized for their exceptional properties such as high hardness, excellent wear and corrosion resistance, and chemical and thermal stability. The plasma jet deposition technology allows the formation of dense layers, well adhered to the substrate, with precise control over the thickness and microstructure of the deposited layer. The study analyzed process parameters, such as spray distance and particle velocity, which influence the microstructure and performance of the deposited layers. The characterization of the layers was carried out by methods such as scanning electron microscopy (SEM) and the composition was determined with the help of the EDX probe. The tribological properties of the WC layer were also investigated.

Most components fail under complex states of stress and for this reason the study of materials failure under these conditions is an important topic. The article presents the experimental study of the failure of a CFRP material, with a 0/90° cross-ply configuration, subjected to both simple loading conditions (tension, compression, and shear) and combined loading (tension–shear), using a modified Arcan testing method. The Arcan device and specimen geometry were redesigned to reduce experimental errors and the dispersion of results. It was found that there are significant differences between the strength values obtained for simple loads performed by the standardized methods and by the Arcan method, respectively. For this reason, it is recommended to use the Arcan method only for mixed loading modes. Specimens with steel tabs were used to reduce both hole ovality during testing and the number of clamping screws to only four. It was found that the experimental results under complex stress states are well described by the Tsai–Hill failure criterion and the failure envelope for the material studied was plotted. Recommendations are provided regarding the appropriate use of the Arcan method in order to obtain precise results for CFRP composites under multiaxial loading.