A fatigue experiment is carried out on filled natural rubber specimens with two different Shore hardnesses (45 and 50) and three different temperatures (23 °C, 60 °C and 90 °C) under uniaxial tension loads. The measured fatigue life data obtained under different displacement loads are used to formulate fatigue life prediction models corresponding to different operating temperatures for the two hardnesses using the peak engineering strain as the damage parameter. The influences of the temperature, the stress softening at high temperatures and the hardness on the fatigue life of rubbers are measured and discussed. The proposed models are used to predict the fatigue life of a rubber mount for a powertrain mounting system. The validity of the prediction model is demonstrated by comparisons with the measured fatigue life data of the rubber mount at 90 °C. A method for determining the damage parameters required for predicting the fatigue life is presented on the basis of the finite element model of the rubber mount. The Mooney–Rivlin constitutive constants of the hyperelastic rubber material are identified on the basis of the measured data on the specimens. Comparisons of the measured and the estimated fatigue lives of the rubber mount at 90 °C revealed reasonably good agreement. The ratio of the predicted fatigue life to the measured fatigue life was within a factor of 2 under the range of loading conditions considered.

Thin-walled structures are widely used as energy absorbers in automotive vehicles due to their lightweight and high-energy absorption efficiency. In order to improve the energy absorption characteristics of thin-walled structures subjected to different loading angles, different types of novel multi-cell structures are proposed in this paper. The numerical method is used to study the crushing behaviors of the proposed multi-cell structures under different loading angles. It is found that the proposed multi-cell structures have considerably small initial peak force under axial load and avoid the appearance of global buckling deformation mode under oblique loads. Moreover, reasonably distributed wall thickness for each square tube in the thin-walled structure can enhance its energy absorption capacity under different loading angles.

Uncertainty widely exists in the powertrain mounting system of a vehicle. The traditional analysis and optimization methods for powertrain mounting system design are often based on deterministic or random models. In this study, an efficient analysis and optimization method is developed for powertrain mounting system design involving interval uncertainty. In the proposed method, the uncertain parameters of powertrain mounting system are treated as interval variables, and an efficient method called as Chebyshev-Vertex method is developed to fast calculate the lower and upper bounds of the natural frequencies and decoupling ratios of powertrain mounting system. Monte-Carlo method is taken as a reference method to verify the calculation. Then, an optimization model is established based on Chebyshev-Vertex method, in which the interval responses of decoupling ratios are used to build up optimization objective while the interval responses of natural frequencies and decoupling ratios are taken to create optimization constraints. The optimization model of the powertrain mounting system with interval parameters is generally a double-loop nested problem, and it is rather time-consuming on calculation. However, based on Chebyshev-Vertex method, the optimization model can be approximately simplified into a single-loop one and the calculation efficiency is greatly improved. A numerical example is provided to demonstrate the effectiveness of the proposed method on the analysis and optimization design of the powertrain mounting system involving interval uncertainty.

To investigate the rotation vibration dynamics of the pulleys and the tension arms, and to estimate the vibrations of the belts and the slip ratio between the belt and the pulleys in the engine front-end accessory drive systems, a systematic modelling and analytical method is proposed for engine front-end accessory drive systems; this can be used for modelling engine front-end accessory drive systems with different layouts and different numbers of tensioners, including automatic and fixed tensioners. In the modelling, the rotational pulleys are classified as fixed-axis pulleys and moveable-axis pulleys (such as the pulley in the tensioner). Moreover, the belt spans are classified as the belt spans between the two fixed pulleys, and the belt spans adjacent to the pulley of a tensioner. The equations of motion for each type of pulley and the tension calculation equations for each type of belt span are developed. In this way, the equations of motion for all the pulleys and the tensioner arms can be obtained easily, irrespective of the layout of the tensioners. To obtain the dynamic rotational vibration responses of an engine front-end accessory drive system by the conventional Runge–Kutta method, high-efficiency algorithms or methods are also proposed for calculating the tangent-point coordinates between a belt and the adjacent pulleys and the belt length of the contact arc on one pulley. The proposed modelling and analysis methods are validated by modelling different layouts of the engine front-end accessory drive systems with different types and numbers of tensioners, and also by comparisons between the calculated dynamic vibration responses of the pulleys and the belts and the real experimental data.