改革高校实验教学体系建立实验技术教学课程

改革高校实验教学体系建立实验技术教学课程中南工业大学刘光连，毛大恒实验教学是高等教育的一个重要教学环节，是课堂教学的必要补充，在巩固学生所学知识，培养和提高学生的实验技能，观察、分析和解决问题的能力上具有特别重要的作用。与课堂教学一样，实验教学总是不...     

桥式起重机小车布置的优化设计

桥式起重机的小车高有起升机构和小车运行机构，为使小车轮压呈均匀分布，应对小车的机构布置进行优化设计。本文以已知小车轨距和轴距的小车为例，以轮压均分配为目标函数，按单钩起重小车的条件提出约束条件，对优化设计的结果进行了分析。     

A novel limiting strain energy strength theory

With applied dislocation theory, the effects of shear and normal stresses on the slide and climb motions at the same section of a crystal were analyzed. And, based on the synergetic effect of both normal and shear strain specific energies, the concept of the total equivalent strain specific energy (TESSE) at an oblique section and a new strength theory named as limiting strain energy strength theory (LSEST) were proposed. As for isotropic materials, the plastic yielding or brittle fracture of under uniaxial stress state would occur when the maximum TESSE reached the strain specific energy, also the expressions on the equivalent stresses and a function of failure of the LSEST under different principal stress states were obtained. Relationship formulas among the tensile, compressive and shear yield strengths for plastic metals were derived. These theoretical predictions, according to the LSEST, were consistent very well with experiment results of tensile, compressive and torsion tests of three plastic metals and other experiment results from open literatures. This novel LSEST might also help for strength calculation of other materials.     

应力控制下的Q345钢疲劳寿命预测研究

基于Gerber模型和Goodman模型这两个考虑平均应力对疲劳寿命的影响的经典模型,提出了一个修正的疲劳寿命预测模型。在室温下,选取3个应力比R=-1、-0.75和-0.5,每个应力比下选取5个最大应力,对Q345钢进行单轴拉压疲劳实验。运用Gerber模型、Goodman模型和修正模型对Q345钢在不同应力比和最大应力组合工况下的疲劳寿命进行预测,并与试验结果进行比较分析。结果表明:修正模型预测寿命和试验寿命的相对误差绝对值平均值、相对误差绝对值最大值、标准差都较明显的小于Gerber模型、Goodman模型。修正模型比Gerber模型和Goodman模型更适合于Q345钢在不同应力比和最大应力组合工况下疲劳寿命的预测。     

试验研究Q345钢和20Cr13合金应变硬化关系曲线

对Q345钢和20Cr13合金进行单轴拉伸试验,获得应变硬化曲线,用于研究两种金属的应变硬化指数n变化规律和应变硬化关系曲线。应变硬化关系曲线的研究从常用金属幂乘关系经验模型和基于应变硬化指数的物理意义建立模型两个方面进行。结果表明:两种金属的n值均不为常数,Q345钢的n值与真应变ε呈幂指函数关系,20Cr13合金的n值与对数真应变lnε呈三次多项式关系;修正后的Swift与Ludwik模型拟合效果要优于原模,且修正的Swift模型要优于Ludwik和Hollomon模型;基于n值的物理意义分别建立的描述Q345钢和20Cr13合金应变硬化关系曲线的两个新模型的拟合效果都优于常用经验模型。     

Analysis of complete plasticity assumption for solid circular shaft under pure torsion and calculation of shear stress

The distribution of shear stress on the cross-section of plastic metal solid circular shaft under pure torsion yielding,the applicability of complete plastic model assumption and the shear stress formula were researched.Based on the shear stress formula of circular shaft under pure torsion in elastic stage,the formula of torque in elastic stage and the definition of yield,it is obtained that the yielding stage of plastic metal shaft under pure torsion is only a surface phenomenon of torque-torsion angle rel...     

对高校教材建设原则的认识

对高校教材建设原则的认识中南工业大学刘光连刘义伦对高校教材建设的原则已有一些学者进行过探讨。这些探讨都具有一定的意义，促进了我国高校教材建设的发展。但是，我国教育在总体上还比较落后，不能适应加快改革开放和现代化建设的需要。教材建设也是这种状况。本文试...     

直边链板的结构优化设计

将优化设计方法和有限元强度分析相结合，建立了直边链板结构优化设计的数学模型，通过对实例的结构优化表明：在链条强度不变时，可显著减轻链板的重量；在链板重量变化不大时，可较大地提高链条的强度。