The automobile industry has shown an increased interest in the use of composite leaf springs due to their high strength to weight ratio. The introduction of composite materials has made it possible to reduce the weight of the leaf spring without any reduction in load carrying capacity and stiffness. In this paper, the results of research on fatigue life of composite (Glass Fiber Reinforced plastic – GFRP) leaf springs are presented. Composite springs were designed in such a way that they could replace steel springs in a van.

This article provides a comparative analysis of the dimensional accuracy and post-surface characteristics of gears produced by the 3D printing technique Direct Metal Laser Sintering (DMLS) from 1.2709 steel immediately after printing and after grinding and grinding treatment. The following tests were performed on the fabricated samples: metallography, hardness measurement, self-stress, surface roughness, and the gears’ shape were dimensioned and measured. The results show that post-processing influences the distribution of residual stress and the printed model’s hardness. The results show that heat treatment results in clear directionality marks and micropores, increasing the material’s hardness to 54.3 HRC ± 0.6 HRC, indicating effective strengthening. Grinding significantly improved the holes’ accuracy, changed the compressive intrinsic stresses to a tensile state, and reduced radial runout, improving gear geometries. In addition, it was noted that different results were obtained for roughness parameters depending on the gear tooth tested.

The paper presents an analysis of the stress distribution in the open, cone-shaped, sandwich shell panel. The shell under consideration consists of two load-carrying facings and a core layer of the soft type. The facings are made of an isotropic, compressible, work-hardening material and they are geometrically and physically symmetrical, so they are of equal thicknesses and the same material properties. The core layer resists transverse shear only. The shell under consideration is under combined external load in the form of lateral pressure and a longitudinal force. Different ratios of the longitudinal force to the lateral pressure are taken into account. In each case, the components of the effective stress as well as the effective stress values corresponding to the shell deformation were determined. To determine the stress state which occurs during the shell deformation, the stability equations have to be derived. The effective stress corresponding to the deformations in the shell under consideration can occur within the elastic, elastic-plastic or plastic range. In order to determine the stress distribution in the shell under consideration which corresponds to the on- and post-critical state, the constitutive relations of the Nadai-Hencky deformation theory, alongside the Huber-Mises-Hencky yield condition, are accepted. Analyses show that, in certain cases, there are very large differences between the values of the components of the stress state. In such cases, it seems to be possible to omit the components with small values

The paper presents investigations of the optimal geometric parameters for the sandwich rectangular pipe. The analyzed parallelepiped shell is loaded with uniform internal pressure. The objective function is the ratio of the shell structure mass to mass of the medium contained in the shell. The minimum of the objective function is searched. The optimization constraints are a geometric conditions relating to the dimensions of the shell, and strength requirements. The solution was obtained and the optimum geometrical parameters are presented.

In the paper the D3 discipline of the G8D method has been presented. In the presented procedure all decisions are made regarding the introduction of interim corrective actions - ICA. The algorithm of conduct for the discipline and the quality management tools that the discipline uses have been also presented. It has been also discusses how to proceed for the D3 discipline in determining temporary corrective actions for the NOK detail with the preceding actions in the D2 discipline.