Papers by Author: Guo Qiang Wang

Abstract: Kinetic characteristics of chain drive system were investigated in this paper and some corresponding mathematical models were established. In accordance with the theory of chain drive, based on the multi-body dynamics software platform, a dynamic analysis model of timing bushing chain system for diesel engine was established. Chain tension force, chain contact force and chain fluctuation in a rotation cycle at different running speeds were analyzed. By analysis and evaluation these results, the kinematic and dynamic characteristics of the chain drive system during the operation could be effectively recognized, this research results can provide a basis for production tests.

Abstract: To realize the structural light weighting design of the transmission components of engineering vehicles on the basis of life in control, this paper took wheel loader as an example, collected the time-domain load signals of the transmission system in typical working conditions, provided processing steps for load spectrum synthesis by a certain percentage, and generated the program load spectrum which consisted of various amplitudes and means. The load spectrum can be used for fatigue loading at the output flange of gearbox. Then, the finite element model of the flange was established, and the stress analysis was carried out in the stress concentration location such as fillet. The prediction method of fatigue life on the base of program load spectrum was given. After the fatigue life prediction based on the compiled load spectrum and the theory of cumulative fatigue damage, the fatigue life of outside fillet of the flange, where is of maximum stress, is obtained. It was possible to obtain adequately fatigue prediction results in engineering vehicle design, using load spectrum, finite element analysis, and a stress-life approach to fatigue damage calculations.

Abstract: This paper is devoted to study of the helmets which can provide protection for the operator against head injury during an rollover accident. In the present study, the proposed procedure is demonstrated with the help of a validated madymo model of a featureless Hybrid Ⅲ headform in conjunction with a helmet model comprising an outer polypropylene shell to the inner surface of which is bonded a protective polyurethane foam padding of a given thickness, a parametric analysis has been performed in order to investigate the effect of different densities and thickness of the polyurethane foam on the head injury during impact. Based on simulation results of impact on a rigid surface, it appears that a minimum foam padding thickness of 15 mm is necessary for obtaining an acceptable value of HIC(d). The HIC(d) value decreases as an increase of the foam thickness, and the effect of the foam density variable is nonlinear, a second order parabolic shape can be identified.

Abstract: To achieve the rational shape and structure of large or super-large track segment, this paper investigated the optimal material distribution law of the track segment with topology optimization by variable density method. In this method the element density of the optimal area is the design variable, the maximum stiffness between the track segment and the terrain is the object, and the material volume per centum of the optimal area is the constraint. In this study, we obtained the topology optimal results of a track segment for a certain heavy-machinery by OPTISTRUCT software. The paper also presented the transitional geometrical distribution law of the optimal material from solid state to hollow state at the same constraint of the material volume percentum and at the different terrain stiffness. Finally, the optimal shape was put into application.

Abstract: The load time history signal of engineering vehicle is usually polluted by various nonstationary and stationary noises in the field test. An approach based on wavelet transform (WT) and fractal dimension (FD) is proposed in order to improve the adaptability and efficiency of denoising. This method initially decomposes the original signal into detail and approximation space in the WT domain by WT-based multiresolution decomposition. The short-time fractal dimension of detail coefficient is calculated at each scale. After the application of the binary processing to the short-time fractal dimensions, the locations where the thresholding of the detail coefficients has to be executed are ensured. The desired load signal is provided by applying WT-based multiresolution reconstruction to the processed detail coefficients and the unprocessed approximation coefficients. The proposed method is applied to an actual load time history signal of engineering vehicle. And the performance of this method is compared with that of the WT-based hard thresholding denoising method. The results show that this method is an alternative way to process the load time history signal of engineering vehicle.

Abstract: This work is devoted to the development of a new type Rollover Protective Structure which absorbs the impact energy using shear energy absorber during a roll-over accident of engineering vehicles. A method is developed for investigate the energy absorption of the shearing processes using the finite element method coupled with the Cockroft-Latham fracture criterion, remeshing and element kill method accounting for nonlinear isotropic and kinematic hardening under the large plastic deformation. Comparing the simulation results with laboratory test results, the proposed method is valid. Using the finite element analysis method, the effects of shearing clearance, cross-section parameters and the shape of the shear edge on shear force and energy absorption of the process are investigated.