The Multi-Body Dynamics Analysis, Experimental Study And Optimization Of Rubber Suspension System Of Articulated Dump Truck

Supported by Jiangsu province Natural Science Fundation pre-research project of dynamics modeling, analysis and optimization of off-road vehicle suspension, dynamic characteristics of AD250 articulated dump truck rubber suspension had been studied through applying multibody dynamics, finite element theory and experiment. The ride comfort of the truck was improved through optimization of the stiffness and damping of rubber suspension. In detail, the contribution of the paper is as following:1. The parameterized nonlinear finite-element model of Hourglass rubber springs and laminated rubber spring used as main elastic component in AD250 suspension have been built, and non-linear stiffness in vertical direction have been analyzed in this paper. The results of the analysis were consistent with experiment results very well. The sensitivity analysis of structural parameter of Hourglass rubber springs was explored to find the law of each parameter's contribution to stiffness in vertical direction, and the most sensitive design variable was found for optimization.2. Vibration experiment of AD250 articulated dump truck was designed and implemented on SCHENCK whole vehicle road simulation experimental bench. Using simulated road excitation simulated the status of practice running on different road and at different velocity, The ride comfort of the truck was evaluated according to RMS acceleration under different running status. The nonlinear dynamics properties of front & rear rubber suspension were comprehended through analyzing acceleration spectrum at the upper and lower point of rubber spring under different load.3. Based on topological analyses of the suspension of AD250 articulated dump truck, nonlinear virtual prototyping of the truck has been built through applying multi-rigid body dynamics theory. The multi-rigid body dynamics simulation analyses have been performed with different velocity & load by using different road spectrum excitation. Simulation error has been analyzed by contrasting test result, which indicated it was an important error source to regard suspension links as rigid body. It provided a basis for building more accurate dynamical model.4. Based on AD250 articulated dump truck multi-rigid body dynamics model, flexiblemulti-body models of suspension components for which the deformations are relatively important were built using finite element method. Modified Craig–Bampton modal synthesis and flexible multi-body methods were applied to build rigid-flexible coupling multi-body model of the truck. Dynamic simulations with different road profiles were performed. The results of analysis were consistent with experiment results very well, which showed the correctness of the rigid-flexible coupling multibody model.5. Based on the rigid-flexible coupling multi-body model of AD250 articulated dump truck, dynamic stress of suspension links was analyzed. The location of the maximum stress was indicated and the dynamic intensity of suspension links was evaluated. This research technology is useful to obtain the dynamic stress distribution characteristics of the suspension links and the dynamic stress history of nodes in the time domain. It provided a basis for evaluating the service life of suspension links in its structural design stage.6. In order to improve the ride comfort of AD250 articulated dump truck, optimization design theory and method of rubber suspension system was studied. An optimization model and a set of optimization method based on whole vehicle dynamics simulation are proposed for improving the truck ride comfort and ensuring handling performance at the same time.7. Based on the rigid-flexible coupling multibody model of AD250 articulated dump truck, the optimization design of the rubber suspension was completed under differ load by using Sequential Quadratic Programming theory. The optimum nonlinear stiffness curve of rubber suspension was obtained through least squares fitting the optimum stiffness values according to certain load. The structure parameters of the Hourglass rubber spring have been optimized for fulfilling the optimum nonlinear stiffness curve. The optimization result indicated that Using of rubber spring with optimum nonlinear elasticity character resulted in good and constant ride comfort of the truck.