Applied Mechanics and Materials Vols. 34-35

Abstract: In order to solve the transmission error from the backlash in precision gear transmission, this paper proposes a mechanism which uses slider and pendulum to eliminate backlash. Based on the force analysis of the new-typed auto-eliminate backlash mechanism, genetic algorithm is selected to optimize the design. The simulation experiment by Matlab shows that spring force of the mechanism is minimum and its performance is ideal, meanwhile the configuration parameters of the mechanism are ensured.

Abstract: In this paper, material properties, geometry parameters and applied loads are assumed to be stochastic, the vibration equation of a system is transformed to a static problem by using the Newmark method and the Taylor expansion stochastic finite element method (TSFEM) is extended for the structural vibration analysis. The optimal design of structural vibration based on stochastic finite element is presented. An example is given respectively and the calculated results are compared to validate the proposed methods.

Abstract: Using the second-order center difference scheme, the difference discrete model of axial symmetry vibration of a circular plate with arbitrary supports was established. In this paper, the stiffness matrix of the discrete model is proved as a sign-oscillation matrix, obtaining the qualitative properties of the axial symmetry vibration of the system. Furthermore, the inverse mode problem was raised and solved. Three examples of the numerical computation were also given in the paper.

Abstract: Green manufacturing is the important manufacturing pattern to achieve sustainable development. The core is to reduce the damage on the environment and to realize sustained rapid economic growth. The Paper establishes evaluation index system of green manufacturing using life cycle theory and the “pressure - state – response” model. The index system is the 3-tier indicator system, a total of 39 sub-indicators, including 17 environmental attributes index, 8 energy property index, 7 resource properties index and 7 economic attributes index.

Abstract: Complex manufacture collaborative design process is a dynamic process with uncertainty, which is a process with multi-task executing in a parallel manner. It has obviously time constraint, which has been few studied up to now. Temporary inference and simulation problem for complex manufacture design process are mainly studied in this paper. Firstly, a Petri net model for collaborative design process is proposed based on time Petri net theory and four temporary inference algorithms of ordering, paralleling, selecting and circling structures in collaborative design process. Secondly, the authors design and develop a visually modeling and simulating circumstance for collaborative design process temporary inference based on time Petri net. Temporary inference for the whole collaborative design process and optimization to design task can be implemented by this simulation software. Finally, collaborative design process for driver of chain-transportation-driven equipment is undertaken to shown the efficiency of the proposed method. Research in this paper affords a determinant principle for time arrangement of collaborative design task and it also affords schema scheduling.

Abstract: Proton exchange membrane fuel cell(PEMFC) technology has been greatly promoted in recent years, but the fault diagnosis and predictive maintenance are unneglectable issues in practical work. According to the safety and reliability requirement of 60kW automotive fuel cell engine designed by our group, a fault diagnosis method based on T-S fuzzy model which is tuned and optimized thanks to particle swarm optimization is put forward in this paper. Its inputs include voltage, the lowest single cell voltage, current, temperature and air pressure, by setting the output threshold of T-S fuzzy model at 0.85,when the healthy degree and its variety rate are below 0.85 and 0.05 respectively, the flooding fault is distinguished, if the healthy degree is below 0.85 but its variety rate is above 0.05,drying of the proton membrane is on-line diagnosed successfully, which can provide a guidance to its real-time monitoring and optimized control in future.

Abstract: Nature of springback in sheet metal forming was analysed in the study, two stress-based objective functions were established to evaluate springback respectively from the stress point of view in an optimization problem aimed to reduce springback. To evaluate springback more comprehensively, multi-objective functions including a stress-based and a strain-based objective function were applied. Results show that when acting in conjunction with strain-based objective function, objective function which is defined on stress component deviation through thickness direction has perfect performance, while objective function which is defined on equivalent stress deviation through thickness direction would work well only when degree of plastic deformation is large for the stamped part. To evaluate the influence of stress position on springback, the parametric coordinate of integration point in thickness direction was also employed as weight factor for those two stress-based objective functions. Accuracy of the proposed two objective functions was also compared with the traditional objective function which is defined on the corresponding nodal distance of the shape before and after unloading.

Abstract: In order to improve the accuracy of stress analysis of blade wheels, one way Fluid- Structure Interaction method was introduced based on the comparisons of existing methods. Finite element analysis software ANSYS along with CFD software FLUENT were comprehensively used for the strength analysis of dual-chamber couplings. According to the simulation results from CFD, the node loads at the interface of pump wheel and the working fluid were obtained and the torque and axial force were predicated. Then the static stress of pump wheel was analyzed with ANSYS. The detail processes were described in this paper. The results show that the blades of pump wheel is loaded by alternating forces, and the maximum stress, which is 64MPa, locates at the junction area of the blades and shell. And the coupling analyzed in this study meets the strength requirement.

Abstract: In this article, seven frontal impact simulation models with same restraint system and different human body models were established through the use of multi-body kinematics software MADYMO. The injuries in head, chest and femurs of different human models and the differences of these injuries were analyzed in detail. The weighted injury criterion was adopted to evaluate the overall injuries of different human body models. The results shows that the injury risk of smaller human body is much higher than the taller human body, and existing occupant restraint system that protects the 50th percentile American occupant well protects other size occupant poorly.

Abstract: Based on the physiological structure of osteon, a single fluid-filled osteon model under only time-dependent axial loading is modeled for calculating the streaming potential induced by canaliculi fluid flow. Solid matrix is modeled as an elastic transverse isotropic thick-walled cylinder and fluid phase is considered as an incompressible Newtonian fluid. Close-form solution of the streaming potential for a single osteon model was obtained and used to study the electromechanical properties on intraosseous pressure and potential distribution. The solution can also be used as a benchmark for numerical studies of other osteon models.