小型组合变形试验台设计及实验研究

机械设计制造及其自动化论文，论文编号:JX1203  论文字数:23673.页数:46

摘    要
 随着科技的不断发展，每个国家对教育也越来越重视，教育成本的投入也越来越大，对实验硬件设施的小型化、智能化、简便性、功能化、经济性等要求越来越高。然而目前我国力学实验台缺点是功能单一、体积庞大、不经济等原因落后与发达国家的实验设施，给教育带来很大的影响，因而对这些实验设备的改造、重新设计将会极大地提高我国的教育水平,带来很好的效果，同时能为国家教育节约大量资金。
 目前在用的弯扭组合实验装置的缺点是: （1）体积偏大。一套实验装置要占用一张试验台。（2）加载机构复杂,要求所加载荷较大。加载机构一般由旋转手轮、砝码等构成, 所加载荷一般在100 ～1000N ,这也是导致此装置体积大的原因之一。（3）实验误差较大。造成实验误差较大的原因是多方面的,有实验装置结构尺寸设计的不合理,应变花的贴片位置确定的不合理和贴片方式不合理等等原因引起的。(4)设备成本较高不利于扩套。(5)功能单一。不能进行多项实验。面对国内教学实验设备如此多的缺点，作为一名亲身体会过实验设备落后给我们接受知识带来障碍的学生，我深刻感受到实验设备落后带来的教育的负面影响，改进和重新设计实验设备对教育事业意义重大。也是我选择该课题意义所在。
 该课题中所改进设计小型组合实验台应具有以下主要特点：（1）小型化实验装置投资省、轻便可移、占用空间少,便于扩套。（2）由于它们是针对实验教学需要开发出来的,具有功能适用、操作方便、故障低、安全性好、实验精度高等特点。（3）可以做到人手一台,有利用于学生独立完成实验。通过单弯、单扭、弯扭组合与扭转剪切弹性模量G的测定掌握电测法，还可以验证理论。主应力测试和内力素（弯矩和扭矩）测试两个实验只粘贴几个应变花就能完成所有的测试内容,为实验教学提供了一种简便实用的方法,提高了实验教学质量。
 本论文通过对国内现状的分析、方案设计，提出了老式弯扭组合实验设备的缺点,通过对所测点处应力应变状态分析,确立了设计超小型化弯扭组合实验装置的理论基础、设计原则,设计出了体积小,加载简单,结构尺寸合理,计算机数据采集、精度高的超小型化弯扭组合实验装置。

关键词：小型化  实验装置  弯扭组合  应变
Abstract
 As to technical increasing development.  Every country is also increasing emphasis on education and the investment in education is also increasing. the requirements to experimental equipment like Small size、Intelligent, simple, functional and economy is becoming more and more strict. However , compared with developed country, our country is relatively backwards in terms of Laboratory equipment because  China''''s equipment has shortcomings of single function、huge size and not economic. This brings great impact on education. Thus the transformation and re-design of the experimental equipment will greatly enhance China''''s education level, bring very good results, and can save a lot for the state education fund.
 Currently the shortcomings of the Combination of bending and torsion experimental device are as follows:
 1. Too large volume.  An experimental device needs to take up a test-bed size.
 2. Complex Loading institutions, requested large load. Loading institutions are composed with hand wheel spin、weight and so on. The general load is 100 ～1000N, which also contributed to this large volume of devices.
 3. Big experimental error. unreasonable designed experimental device 、unreasonable rosette location of the patch and unreasonable way of patch can cause big experimental error.
 4. High cost of equipment is not conducive to expansion sets.
 5. Single function. Incapable of dealing with a series of experiments. Our country’s teaching laboratory equipment exist so many shortcomings, Improving and re-designing equipment has great significance to education. That’s why this subject is choosed.
 The improved design of small experimental combination of this subject has the following main features:
 1. Low investment, convenient take up less space, facilitate the expansion sets
 2. Easy to operate, low-fault, safety, and high accuracy because they are based on experimental teaching needs.
 3. Each student could have one, help students complete an experiment independently. And also can verify theory by the comparison of Single-bending, single-twisting, bending and twisting combination and reverse shear elastic modulus G. providing simple and practical ways to experimental teaching as well as improving the quality of teaching.
 In this paper, shortcomings of Old-fashioned combination of bending and torsion test equipment are raised through analysis of our country’s situation and program design. The theoretical basis and design principles of ultra-small experimental device combination of bending and torsion are established by measuring point state of stress and strain. An ultra-small experimental device combination of bending and torsion is designed with the feature of small volume、simple to load reasonable size of the structure and high accuracy.
Key words: miniaturization  experimental device  combined bending with torsion                    
strain
 
目录
摘   要 i
Abstract ii
目录 iv
 第一章  绪论 1
 1．1  课题背景 1
 1．2  国内外技术现状 2
 1．3  课题的提出和解决思路 3
 1．4  本章小结 3
第二章  原理分析和方案设计 4
 2．1  功能原理分析 4
 2．2  方案设计 5
 2．2．1  弯扭组合方案设计 5
 2．2．2  测G模量方案设计 7
 2．3  方案的确定 8
 2．4  本章小结 9
第三章  实验台的结构设计 10
 3．1  总体方案分析设计 10
 3．2  小型化组合实验机构装置的设计 14
 3．2．1  小型化组合变形装置主构件————薄壁不锈钢管的设计 14
 3．2．2  小型化组合变形装置底座————底板的设计 17
 3．2．3  小型化组合变形装置支撑座————固定支座的设计 17
 3．2．4  小型化组合变形实台加力装置————加力杆的设计 18
 3．2．5  扭转测G附件及转角指示器的设计 19
 3．3  本章小结 22
第四章  实验台的数据采集 23
 4. 1  数据采集原理——电阻应变桥 23
 4. 2  采集仪器——DH-3818静态电应变仪采集数据 25
 4．2．1 概述 25
 4．2．2 技术指标 26
 4．2．3 工作原理 26
 4. 3 “自动控制”软件使用 29
 4．3．1 软件的启动 29
 4．3．2 软件界面介绍 30
 4．3．3 创建一个新的测试项目 30
 4．3．4采集控制 33
 4．3．5 测试项目管理 34
 4. 4 本章小结 35
第五章  实验的步骤和误差分析 ...36
 5．1 实验步骤的编写 36
 5．1．1组合变形实验台的机械安装调试 36
 5．1．2弯扭组合变形、主应力、主方向测定及弯矩、扭矩分离实验 37
 5．1．3 纯扭转侧G实验 37
 5．2 实验结果误差原因分析 38
总结 39
参考文献 40
致谢 41