Digital Test Platform System Study On The Roll-over Protective Structures Of Engineering Vehicles

Engineering vehicles generally include loader, excavators, rollers, bulldozers, graders, loaders mining, industrial tractors and dumpers, they are usually used in construction, agricultural, mining, water conservancy, road construction, etc. Roll-over accidents often happen because of large deadweight of engineering vehicles, bad stability of full-scale vehicle the complexity of the road and poor working environment. The drivers'life is often threaded by such kind of incidents. Roll-over protective structure (ROPS) is the most effective method to protect drivers'life in the engineering vehicle roll-over presently. ROPS is a group structure installed outside the vehicle cab, and its main function is to safeguard the lives and safety of the drivers when the vehicles encountered roll-over, and minimize the damage caused by the accidents. However, the current design methods for ROPS are not yet perfect. This dissertation is based on "Digital design platform of safty for Roll-over and Falling-object of engineering vehicles", which is supported by national program 863. According to the key problems of design method of ROPS, digital test platform system study on the Roll-over protective structures of engineering vehicles is discussed detailedly in this dissertation. The research results have improvement to the development of the digital design method to ROPS, and have important significance to the development of improving the Roll-over protective structures of engineering vehicles.On the basis of referring to relevant literatures of ROPS extensively, this dissertation summarizes the study status of engineering vehicle ROPS. Based on elasto-plastic structural mechanics method, ROPS digital computing platform is developed through the application of MATLAB's GUI features. Through the application of finite element software ANSYS, finite element calculation and analysis of stiffness, strength and energy abosorption is conducted to ROPS by use of its material nonlinearity and geometric nonlinearity. Parametric FEA software of ROPS is developed, and the digital test platform is set up based on ANSYS. The main working and contents are as follows:(1) The international standard ISO3471 are described, and the performance requirements and test method to ROPS of engineering vehicle are discussed, which provides basis to the method of design calculation, computer simulation and performance test of ROPS.(2) The deformation process and design criteria of ROPS are discussed, and the analytical calculation and finite element calculation are conducted to the deflection and limit load according to international standard. Through comparing this two calculation, it shows that the error different is little, which illustrates the analytical calculation has reliability, and it is feasible that hypothesis is carried out to the simplified model of ROPS non-linear design.(3) Through the ROPS digital computing platform developed by use of the GUI function of MATLAB, it is realized that plastic limit load of ROPS and the displacement in different deformation stage can be calculated only need to input the basic parameters of ROPS. It can make desiger detach from the miscellaneous manual calculation, improving the design efficiency of ROPS, and the design can predict some peoperties of ROPS at the beginning of design.(4) Secondary development is carried out in ANASYS using the UIDL language and the APDL. Through the interfacial menu and dialog box, the APDL macro file in target directory can be called derictly to modeling analysis and realize the parameters design. User can modify the parameters to design analysis, and estanblisd structure and function they need according to the prompt of the software interface. Finally, post-processing is carried out to the process which is analyzed, and detailed and reliable data as displacement cloud chart, stress cloud chart, loading force and displacement curve, loading force and energy absorption curve, etc. And the ROPS digital text platform based on ANSYS is establisded.(5) On the basis of the digital test platform system for ROPS, ROPS simulation model of engineering vehicle is established taking two-column ROPS as example, and a numerical simulation is carried out. Lateral energy absorption capacity analysis, vertical load-bearing capacity analysis and longitudinal load-bearing capacity analysis are completed. Finally, taking the lateral energy absorption capacity as an example, the computer simulation results agree with test well indicates the accuracy of the computer simulation.