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This study considered the solution of the stochastic vibration of nonlinear mechanical systems with Gaussian random excitations. It realised a short review of linearisations techniques in stochastic dynamics mainly with application in the area of truss finite element modelling. The presented method of statistical linearisation is applied to numerical testing. In the second part of the article, the sensitivity analysis of the first two stress statistical moments and structural weight minimising subjected to the random stress constrains presented by mean value and standard deviation was brought to the fore. Cross-sectional areas were used as optimising parameters.

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This article is divided into two parts—in the first part, authors inform about their testing device that enables the acquisition of results from uniaxial and multiaxial fatigue tests (the bending−torsion combination). We present the approaches used during designing and building the testing device. The direct implementation of the research in the second part will concentrate on implementing the acquired results for the frame design of a vehicle worked out by the authors. The three-wheeled vehicle has the front steered wheel suspended in an unconventional way. This original design can cause an increased load on the vehicle’s frame. This can be apparent mainly during driving through curves. Therefore, the fatigue curves of the tested material (EN AW 6063) will be implemented from the point of view of its usability in operation. A vehicle frame is most often loaded by bending and torsion. The authors assess the influence of welding on the fatigue life of this unique unconventional vehicle by determining the fatigue curves of the material for its production. The stresses achieved on the test specimens fully correspond to the load of the frame (in welds) during its operation.

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The paper deals with experimental simulation measuring and the analysis of defect distribution in passenger car tire under dynamic loading. The main reason for detection of defect extension is to recognize an influence of closed air, small bubbles, separations in tire and it is mainly connected with its quality during its service in a vehicle in terms of road safety. This analysis should help constructors to solve critical conditions in tire casing, whether material selection and individual components proportions are suitable and fit or even the whole construction of tire casing is suitable. The reason for detection of internal defects in tire casing is to avoid the wear of those tires which already contain some internal defects and already recognised separations, which could propagate during the movement of vehicles. This is closely connected with the occurrence of tire destruction and the main purpose is to prevent its critical status and later vehicle crash and human life menace.