The Research And Development Of The3500KN Static Load Testing System

According to the demand of large tonnage, horizontal structure tension and compression testing machines in the market, this project aims to develop a3500KN static load testing machine, which can conduct the loading tests of a variety of specimens, such as rope, chains, hooks and crane structures and complete the different kinds of tests like tension, compression, bending and twisting through different fixtures. This testing system provides a constant displacement rate loading mode, constant force rate loading mode and constant strain rate loading mode.The main innovation of this project lies in three parts. Firstly, the adjustable mechanical structure of the system allows different loading stroke, from2.5m to12.5m, different specimen height, from0.565m to1.725m and different testing types like tension, compression, bending, twisting and other tests by different fixtures. Also it has high bearing capacity and favorable expansibility.Secondly, the electro-hydraulic proportional loading system based on the proportional flow rate control valve and proportional relief valve has been successfully applied to the testing platform and has achieved good control effect, reducing the hydraulic system development cost and energy consumption, meeting the requirements of design. Thirdly, the control system can conduct most of the tests automatically. Most of its functions such as test load operations, data display, data storage and printing can all be completed on the PC monitor screen.The main content of the dissertation is concluded as following.In Chapter1, the paper analyzed the advantages and disadvantages of the existing testing machines, expounded the main problems existing in the current testing machines, crystallizing the direction of the research.In Chapter2, the paper disserted the overall design scheme of the testing machine. At the beginning, the paper elaborated the main design indexes and parameters of the testing machine. Then it concluded the general plan and working principles. Finally it discussed the design of electro-hydraulic proportional loading system and the host system. Comparing the advantages and disadvantages of other hydraulic loading systems, the paper chose the electro-hydraulic proportional loading system based the proportional flow rate control valve and proportional relief valve finally.In Chapter3, the paper conducted some design calculation of the hydraulic system and finite element analysis to the key components of the testing platform using ANSYS Workbench and optimized the mechanical structure to improve the reliability and economy.In Chapter4, the paper modeled the proportional relief valve and proportional flow rate control valve on AMEsim and conducted some simulation. The results show that this loading system can achieve the constant displacement rate loading mode, and constant force rate loading mode. Its precision and responsiveness meet the design requirements.In Chapter5, the paper established the hardware platform of the electrical control system and developed control program. Also, the author developed the prototype of the testing system and conducted some tests based some kind of rope. Through the real tests, the results were ideal and the control system can be transplanted to the test platform of3500KN.In Chapter6, main research work and some innovations of the dissertation were summarized and some future research work is predicted.