Prediction of the elastic behaviour of hybrid and non-hybrid woven composites

A micromechanical model called MESOTEX is presented for prediction of the elastic behaviour of composites reinforced with non-hybrid weave (plain weave, satin weave and twill weave) and hybrid weave (hybrid plain weave and hybrid twill weave) fabrics. By using the classical thin laminate theory applied to each woven structure, this analytical model takes into account the strand undulations in the two directions and also integrates the geometrical and mechanical parameters of each constituent (resin, fill and warp strands). A representative volume is chosen for each woven composite and the fibre architecture is described by several functions. To determine the effectiveness of this analysis, the elastic properties predicted for each woven composite are compared with experimental results and results extracted from the literature. This correlation shows excellent agreement between measured and predicted values, with a very low calculation cost (CPU time of less than 0·01 s).     

Robust pole assignment for incomplete nonlinear decoupling applied to robots

A robustness analysis and synthesis for incomplete nonlinear decoupling for a class of nonlinear systems is discussed. Rigid and elastic-joint robot models belong to this class. For the elastic case, a transformation facilitates the robustness analysis under a weak assumption. Charts with H ₁- and H - norms of closed-loop disturbance transfer functions of the nonlinear-decoupled system are presented for a robust pole assignment.     

经济型矿用无极绳绞车控制装置设计

介绍了经济型矿用无极绳绞车控制装置的组成、工作原理、硬件及软件设计。该装置以主控制箱为核心,可实时检测速度信号和绞车运行信息,并可将信息实时显示在触摸显示屏上,具有绞车启停、正反向控制、调速和自动加减速控制、机头机尾过卷、启车预警、岔道告警等功能;当绞车出现故障时能够立即停车,确保绞车安全运行。该装置既可以作为无极绳绞车的软启或直启控制系统,又可以作为无极绳绞车变频控制系统。     

The effect of α phase on the deformation mechanisms of β titanium alloys

The effects of α and β phase interactions on the tensile and creep deformation behavior of β titanium alloys was studied using Ti-6.0wt.% Mn and Ti-8.1wt.%V as the model two-phase alloys, and Ti-13.0wt.%Mn and Ti-14.8wt.%V as the single-phase β alloys. The β phase of α-βTi-8.1V deforms by stress-induced hexagonal martensite (α′), while slip and twinning occurs in the single-phase β alloy with the same chemistry as the β phase. No stress-induced martensite was observed in the β or α-βTi-Mn alloys. This behavior is modeled in terms of a number of factors, including elastic interaction stresses between the α and β phases, coherency between the α phase and hexagonal martensite, and β phase stability. This paper was presented at the Beta Titanium Alloys of the 00’s Symposium sponsored by the Titanium Committee of TMS, held during the 2005 TMS Annual Meeting & Exhibition, February 13–16, 2005 in San Francisco, CA.     

压入深度与膜厚对薄膜与基体复合硬度及弹性模量的影响

根据高华建的复合弹性模量模型，提出了用一个测点的载荷-位移曲线计算整个压入深度内薄膜和基体复合硬度分布的方法，探讨了压入深度与膜厚对硬度与弹性模量测量值的影响，指出可由膜-基复合性能反推膜本身的性能。     

熔模铸造型壳抗弯弹性模量的研究

依据材料力学、陶瓷材料的有关理论和方法,分别对水玻璃型壳、硅溶胶型壳及其复合型壳在不同温度时的抗弯弹性模量进行了测试研究.结果表明,耐火材料、温度对型壳的弹性模量有较大的影响,硅溶胶型壳和复合型壳的弹性模量值比水玻璃型壳的大.     

大型弹簧钢片开裂原因分析

为保证大型弹簧钢片在热处理过程中，不发生开裂和翘起度超差，重新制订了热处理工艺。通过增加高温回火、降低淬火温度、加快冷却速度等手段，获得了最好的效果。     

轴类零件校直工艺广义预测多步算法研究

本文基于行程控制的轴类零件校直工艺公式 ,构建了模拟轴类零件校直工艺过程的广义预测控制模型 ,应用广义预测算法 ,实现了对轴类零件弹塑性非线性残余变形的均匀控制 ,实验研究表明 ,该方法能满足精密校直要求 ,并且随着控制步长的增多 ,控制效果显著。     

AB INITIO CALCULATION OF THE ELASTIC AND OPTICAL PROPERTIES OF Al_3Sc COMPOUND

The ab initio method has been performed to explore the elastic and optical properties of Al3Sc compound, based on a plane wave pseudopotential method. It can be seen that the calculated equilibrium lattice parameter and elastic constants are in reasonable agreement with the previous experimental data. The elastic constants satisfy the requirement for mechanical stability in the cubic structure of the Al3Sc compound. The optical property calculations show that a strong absorptive peak exists from 0-15eV and a relative small absorptive peak exists around 30eV. The form is caused by the optical transitions between high s, p, and d bands, and the latter results from the optical transitions from high s, p, and d bands to the low 2p band.