Applied Mechanics and Materials Vols. 101-102

Abstract: By assuming that the random parameters of a continuum structure obey the normal distribution, this paper utilized “normrnd” function in Matlab software to generate pseudo random numbers, analyzed structural stress by using finite element method, conducted topology optimization by using k nearest neighbor (KNN) method, and as such, the continuum structure has been stochastic topology optimized. The paper put forward the concept of “stochastic topology optimization”. Numerical examples are given. The results show that the stochastic topology optimization of continuum structure with random parameters is necessary.

Abstract: This paper presents a laser trigonometry system measuring a micro cantilever’s vibration. The system includes a semiconductor diode laser, a short-focus optical system, PSD (Position Sensitive Detectors) and its signal enlarging system, and data collection system. The system can be used to measure the vibration data of micro frictional pairs. Compared with image method, the measuring frequency is higher and more accurate.

Abstract: Double crank indexing cam mechanism is a coaxial layout of the new sub-degree institutions. In comparison with the conventional indexing cam mechanism, the double crank indexing cam mechanism has a more compact structure due to the coaxial input/output arrangement, and enables more stops to be produced at the same input speed. This paper introduces a dynamic model of the cam system by taking this mechanism as research object, and makes systematic analysis about the constrained forces of the new mechanism. On that basis, the effectiveness of the approach is validated by the examples. The results of the study provide important theoretical foundation for the working of this new mechanism.

Abstract: Working unit in hybrid excavator is an open linkage with three rotary joints, including arm joint, boom joint and bucket joint. This research builds several coordinate systems in the joints, then it sets and calculates the kinetic parameters of working unit by the D-H method, and the result is achieved that relationship between any two parts of hybrid excavator’s working unit can be founded. Based on the result, a kinetic and dynamic model of the energy regeneration system of hybrid excavator can be studied easily.

Abstract: Adhesive bonded single lap joints are used extensively in the manufacture of automobile structures. However, the joints involve many factors such as the overlap, the adherend thickness, the adherend yield strength etc. Therefore, strength prediction is a controversial issue. In order to quantify the effects of various variables, Latin Hypercube method was used to design the tests of simulation in the present study. The failure load predictive equation involving the factors of the overlap, the adherend thickness, the adherend yield strength, the adhesive thickness, the test speed and the adhesive toughness were achieved. The tests of single lap joints in tension load were carried on; while the results form experiments and formula were compared to verify its validation for strength prediction.

Abstract: This paper presents a novel 4-DOF (Degree of Freedom) parallel manipulator called 2-PSS&(2-PRR)R manipulator. Firstly, the architecture of this manipulator is described and the mobility is analyzed via screw theory. Secondly, the inverse kinematic analysis including position analysis and velocity analysis is performed. Finally, the Jacobian matrix is obtained through velocity analysis, and then three kinds of singularity configurations are observed in virtue of the Jacobian matrix. This paper lays the foundation for further research of this manipulator.

Abstract: This article discusses how to apply sensor mixture, modern image handle and computer vision technology to analyse and to deal with the feature messages of the ground work piece surface flaw, and computer how to apply the filtered feature messages to identify these flaws. Result shows that this system can find the defect work piece real time from the images for testing.

Abstract: With continuous development of macromolecule technology and great invention of advanced materials with high quality, plastic parts are widely applied in the areas like aerospace, mechanism and medical instruments. However, the design methods of plastics are still restricted in many aspects. This paper proposes an integrated method for plastic product design, which has been demonstrated by a case study as feasible and effective.

Abstract: Aerodynamic design of launch vehicle is facing combinatorial explosion problem caused by modular design. In order to get basic feasible solution from huge design space, the efficiency of design and simulation must be improved. In this paper, a parametric modeling and simulation method is proposed, which is based on CAD/CFD tools. Firstly, the design Variables of the launch vehicle are divided into three categories: size parameters, configuration parameters and mesh parameters. Secondly, parametric geometry model, including size and configuration parameters, is obtained by secondary development of Pro/ENGINEER. Thirdly, parametric mesh files for CFD are generated by implementing CFD-GEOM with scripts written in Python. By specifying boundary conditions through command stream of GAMBIT, FLUENT software will run automatically to calculate the aerodynamic performance of the launch vehicle. Finally, a graphical user interface (GUI) is developed using VC++6.0. With this system, the integration of CAD/CFD application is achieved. As long as designers enter certain design parameters in the GUI, they will quickly achieve 3D geometry model and aerodynamic performance of the launch vehicle. Application examples show that, this system can significantly improve the efficiency of aerodynamic design of the launch vehicle, and the data error between simulation and experiment is less than 10%, which is acceptable.

Abstract: The rolling bearing test rig for heavy vehicles often works under heavy load and high speed, thus it requires high performance for the main shaft and mechanical structure. In this paper a design of test rig for high-speed railway rolling bearings is presented, in which a new structure is adopted to reduce the load on the support bearings. The basic idea is to position the load in a way that they can be balanced by each other.