差动光栅在精密测试中的应用

提出差动光栅概念,举例说明差动光栅在光纤面板刀口响应测试和材料形变自动监测系统等精密测试中的应用。     

Development of temperature compensated high elongation resistance strain gauges for use up to 250°C

The paper describes the development and evaluation of temperature compensated high elongation resistance strain gauges for use from room temperature to 250°C. These gauges could be temperature-compensated on steels with coefficient of thermal expansion α = 11 ppm/°C. Thermal output within 250°C was about 1 μm/m/°C and maximum standard deviation of 5 gauges was 34 μm/m. Strain limit was > 4% at room temperature and at 250°C. Gauge factors of different strain ranges at R.T. and at 250°C are tabulated. Some applications are stated.     

4TYD112型离心空压机联轴器故障的分析及处理

对新冶钢动力厂制氧机组配套的原料空气压缩机故障现象进行了原因分析,并有针对性地提出了处理措施,经运行检验,故障基本消除。     

Electron microscopic observations and DNA chain fragmentation studies on apoptosis in bone tumor cells induced by ~(153)Sm-EDTMP

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Energetics of Plastic Deformation of Metastable Austenitic Stainless Steel

The change in the internal energy during uniaxial tensile deformation of austenitic stainless steels EN 1.4301 (AISI 304) and EN 1.4318 (AISI 301LN) was determined by measuring the extent of γ→α'‐martensite transformation and the temperature increase of the samples. From the results the fraction of the stored energy of cold work and the free energy change related to the strain‐induced γ→α'‐martensite transformation were determined. The fraction of stored energy varied around 0.4. With the metastable steel grades the free energy change related to the γ→α'‐martensite transformation was found to vary between ‐98 MJ/m³ and ‐206 MJ/m³ depending on the austenite stability of the steel. Furthermore, the magnitude of the mechanical driving force was estimated by comparing the results with the free energy change of thermally induced transformation.     

铁铝酸盐复合膨胀水泥化学预应力机理及其应用研究

本文阐述铁铝酸盐自应力混凝土的主要物理力学特征.研究了限制膨胀应变与配筋率之间的定量函数关系.通过正交试验和方差分析,确定了复合外加剂对其性能的影响.针对其在自应力管中的应用,提出多层中空圆柱理论计算模型,按弹性理论计算出自应力管初始应力分布规律.对比以前的线性理论计算误差,给出相应的修正系数.本文对类似的自应力混凝土,具有普遍的指导意义.     

Hardness-stress-strain correlation in aluminium—A simpler alternative to visioplasticity in metal forming

Local stress and strain variations in the deformation zone can be ascertained by measuring hardness. Hardness is correlated with strain and stress. The expressions discussed later are useful in determining the local variations in stress and strain from hardness measurement. It is a simple method compared to visioplasticity. One can estimate the forces required for a forming process. It helps in the choice of equipment, design of tooling and selection of lubricant for the particular process.     

填充HDPE复合材料基体结晶形态的控制因素

本文以HDPE/玻璃微珠和HDPE/CaCO₃体系为研究模型,通过扫描电镜、红外光谱、偏光显微、小角激光散射和材料力学性能实验等方法考察了这两种体系的界面粘结性、填料含量、粒径及试样成型冷却速率等与其材料性能及基体结晶形态变化间的关系。实验结果表明;在复合材料试样成型过程中,因基体树脂冷却收缩而产生的界面应力可干扰基体中球晶的生长环境,应变诱导填料颗粒周围基体树脂的结晶,促使其表面伸展链晶体结构的形成,并由此而明显改变了复合材料的耐热性;复合材料的界面粘结性是产生这种应变诱导作用,并控制异相结晶的关键。     

Inverse Analysis of Axisymmetrical Compression of HSLA Steel

The objective of the present work is to further explore the problem of selection of the flow stress function which will give the best agreement with experiments for a wide range of the Zener‐Hollomon parameter. Analysis of various flow stress functions was performed, with particular emphasis on the Zerilli‐Armstrong model. Inverse analysis was successfully applied to identify the flow stress model for microalloyed steels deformed in ferrite, two‐phase and austenite regions. Inverse method is applied to interpret the results of the axisymmetrical compression tests performed for HSLA steel samples on a Gleeble 3800 and Split Hopkinson Pressure Bar. Sensitivity analysis is performed based on local and global methods. The objective of the sensitivity analysis in the present study is the evaluation to what extent the selected coefficients in the rheological model influence the result of simulations. In the considered tests this result is represented by two dependent variables, the load and the shape of the sample (barrelling). It is confirmed that the Zerilli‐Armstrong equations should be applied at very high strain rates. Physical meaning is an advantage of this model. Difficulties with identification are the main disadvantage.