| The material testing machine is a very important precision testing device,which is mainly used to measure the mechanical properties,processing property,internal defects of metal or non-metallic materials,mechanical parts and check the dynamic unbalance of rotating parts and so on.It also helps to study and discover new materials,new technologies and new technologies and so on.It also helps to study and discover new materials,new process and new technologies and so on.For the testing method of the material testing machine,the tensile test method is relatively simple,The calculation method used in the test is very easy to understand and apply,and can get more accurate test results.It has a wide range of application.This paper based on the review of the development of material testing machines at home and abroad,a new type of small non-contact tensile testing machine for mechanical properties of materials is developed.The test machine adopts a horizontal structure,compact and convenient to use.It has greater loading force than other small micro test machines,and has accurate control system and measuring system.In addition,it combines the traditional test technology and digital image correlation method testing technology,facilitating the analysis and processing of test data.The main contents of this paper include the following parts:1、The design of the mechanical structure of small non-contact tensile testing machine for mechanical properties of materials is carried out,the main parameters of the test machine are determined,the programme of the drive unit and the transmission unit is designed,the selection of the ball screw and motor is completed,the structure of the fixture and other parts of the test machine is designed,and the finite element analysis of the ball screw and the loading table is carried out.Their reliability is proved.Finally,the overall structure of the tester is designed by UG.2、The hardware of the test machine measurement and control system is designed: including the motion control system,the data acquisition and processing system and the image acquisition and processing system.First,the different schemes of the motion control system are studied,the "PC+ motion control card" scheme is selected preferentially for motor drive.This scheme has a more open and flexible control mode.The motion control card is PCI-1220 U of the Yanhua company,and research on the use of control card and motor.Secondly,the different schemes of the data acquisition and processing system are studied,and The "NI USB-6366 data acquisition card" is selected preferentially to collect the signal of the sensor,This scheme has the advantages of short development cycle,convenient and flexible design.The selection and research of force sensor and displacement sensor are carried out.Finally,The CCD camera,camera and light source needed for image acquisition and processing system are selected.3、The software of the test machine measurement and control system is designed: Using virtual instrument development platform LabVIEW,graphical programming language to carried out the PC programming.The control principle of motion control system is analyzed,and the control program of the motor is written by the LabVIEW function module which is developed by the YanHua company.Then the principle of data acquisition is studied and the program of data acquisition and processing is written on the basis of DAQmx drive.Finally,based on the Iterative gradient algorithm for sub-pixel displacement measurement of nonlinear optical flow equation,the image processing and calculation process of the tester is developed.4、The test machine is tested and verified: first,the sensor and the camera are calibrated,then determine the size and shape of the sample,Aluminum alloy 6061 was selected as the sample material for tensile test,and the whole process of the test is designed.The test results are in good agreement,which proves that the developed tester has good practicability and reliability. |
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