Experiment investigation on effects of elastic modulus on cavitation erosion of silicone rubber

Research into cavitation phenomena in various fields shows that the elastic modulus of a boundary has a potential impact on cavitation erosion. To obtain the direct relationship between the elastic modulus of the boundary and cavitiation erosion, single-layer samples with different chemical composition and moduli, and double-layer samples with different elastic moduli and the same surface layer material, were prepared with silicone rubber. The results of cavitation experiments on single-layer samples, show that the coating chemical composition and mechanical properties together affect the cavitation morphology of the coating, and dominant factors vary with erosion stage. Through the cavitation test of double-layer samples, it was found that there is a positive correlation between the elastic modulus of the coating and the degree of cavitation. This study helps us to understand the relationship between coating elastic modulus and cavitation more directly, and provides theoretical and technical guidance for the application of anti-cavitation for elastic coating in engineering.     

基于虚拟仪器技术开发的超声弹性模量测量系统

本文利用脉冲回波法，通过声速测量材料弹性模量，基于虚拟仪器技术发挥软件算法的优势提高测量精度。通过研制超声脉冲收发卡，编制弹性模量测量系统软件，开发了超声弹性模量测量系统。     

Point load determination of static elastic moduli using laser speckle interferometry

Electronic speckle interferometry (ESPI) is used to determine the Young's modulus E and Poisson ratio ν of an isotropic material. Micron scale deformations of the surface of the block of polymethyl-methacrylate (PMMA) are induced by normal application of a known near-point force. These deformations are recorded in speckle interferometric fringe patterns. An iterative minimum error inversion technique is developed to obtain the elastic properties from the positions of fringe peaks and troughs observed in the fringe patterns. Sensitivity tests of the method on calculated fringe patterns using measured experimental uncertainties suggest the technique will provide measures of the elastic moduli to better than 5%. In an experimental test on a bloc of PMMA (acrylic) the technique gave values of E and ν that differed from corresponding measures obtained using more conventional strain-gauge methods by less than 4%.     

Field-dependent elastic modulus and damping in pure iron, nickel and cobalt

Measurements of the ΔE-effect and magnetomechanical damping are reported for crystalline pure iron, nickel and cobalt bars. An automatic experimental system for measuring both magnitudes simultaneously has been used, taking advantage of its improved features which make it possible to include stress-dependence and path-dependence (due to magnetic hysteresis loop) studies in this work. Our results not only provide a useful qualitative comparison among the magnetoelastic behaviour of these three classic ferromagnetic materials, but also show a useful set of quantitative ΔE-effect and magnetomechanical damping values.     

Influence of internal stresses on field-dependent elastic modulus and damping in pure nickel

Measurements of the ΔE-effect and magnetomechanical damping are reported for crystalline pure nickel under several states of internal stresses. The different internal stresses are obtained by means of a wide variety of heat treatments and studied via microscopic examination and measurement. The influence of the heating temperature, the heating time and the cooling method on the magnetoelastic properties is studied. Our results make it possible to select the most suitable heat treatment for each application and to optimize the magnetoelastic response of nickel. Relative variations from 2% to 13% can be obtained in the ΔE-effect, whereas relative variations from 40.0% to 99.9% are possible in magnetomechanical damping, in terms of specific damping capacity.     

Bulge deformation measurement and elastic modulus analysis of nanoporous alumina membrane using time sequence speckle pattern interferometry

Nanoporous alumina membranes containing parallel regular pores of uniform size and normal to substrate surface were fabricated by anodically oxidizing high purity aluminum foils in acid solutions. The continuous out-of-plane displacement and current load of the porous membranes were obtained through bulge test combining time sequence speckle pattern interferometry (TSSPI) observation system. Then the deformation of whole field under different loads was deduced through point-to-point scan analysis and the elastic modulus was calculated through an analytical model. Measurement of mechanical properties indicates unusual mechanical behavior of these anodic alumina films compared with bulk alumina materials or dense alumina films. This method is useful and convenient for mechanical test on membranes with such structure and bring further understanding on connecting of micro–meso structure and mechanical properties.     

倒挂式弹性模量测量仪

设计了倒挂式弹性模量测量仪,消除了传统悬挂式仪器的诸多弊病,简化了仪器的调节并减小了测量误差.     

Elastic modulus of suspended purple membrane measured by atomic force microscopy

We have probed the mechanical properties of purple membrane (PM) in a physiological environment using the atomic force microscope (AFM). By suspending PM over nano-trenches, the elastic properties of PM can be evaluated free from the interaction with the substrate. Force-displacement curves were obtained on the suspended membrane and the data was compared to that of a simple model of a thin film over a trench. By fitting the data to the model, the elastic modulus of PM was estimated to be 8 MPa. When the membrane is repeatedly indented, we observed a change in the force-distance data consistent with damage to the two-dimensional crystal of PM. In this paper we demonstrate that the AFM allows us to evaluate the mechanics of biological membranes in their native conditions.     

利用电容器测量杨氏弹性模量

提出用可变电容器测金属杨氏弹性模量的新方法，并从实验上测定了碳钢丝的杨氏弹性模量。     

横梁弯曲衍射法测玻璃杨氏模量的改进

设计、制作了横梁弯曲衍射法测物质材料的杨氏模量仪器,并利用单缝衍射测量了火石玻璃挠度的变化,实现了螺旋加力装置配合拉力传感器对拉力连续、稳定控制.     

利用激光干涉测钢丝的杨氏弹性模量

分析了在洛埃镜干涉装置中等效双狭缝间距变化对干涉条纹密度的影响。导出了钢丝因受力引起的绝对伸长量与干涉条纹密度变化之间的关系 ,并通过它计算了钢丝的杨氏弹性模量。结果表明 ,激光干涉法不仅比光杠杆法测量的量要少 ,而且用该方法通过测微目镜测条纹的位置要比光杠杆法通过望远镜对标尺读数精确 ,其测量结果要比光杠杆法更准确可靠     

Anisotropy in elastic modulus of hydrogel containing magnetic particles

We derive the analytic expression of elastic modulus for a gel containing magnetic particles with a magnetic dipole moment. The obtained elastic modulus is anisotropic and the modulus increases and decreases with the density of magnetic particle when the direction of strain is perpendicular and parallel to the direction of magnetization, respectively. This behavior is qualitatively in good agreement with previous experimental data [T. Mitsumata, et al., Macromol. Rapid Commun. 23, (2002) 178].     

激光超声技术测量高温下蓝宝石单晶的弹性模量

利用纳秒激光脉冲所激发的超声纵波, 非接触地测量了蓝宝石单晶沿c轴方向的弹性模量 C₃₃随温度的变化关系. 结果表明, 在室温到1000 ℃ 的范围内, 蓝宝石的弹性模量C₃₃随温度T的升高而减小, 两者之间近似呈如下二次关系: C₃₃ = - 1.541× 10^-5T² - 0.021T + 498.3. 由于该方法利用激光烧蚀效应激发出了强度很大的纵波, 因此对弹性模量的测量具有较高的精度, 估算C₃₃的测量误差不超过0.1%.     

利用光的干涉测钢丝杨氏弹性模量的方法

通过测定空气劈尖的光的干涉条纹间距,确定钢丝的微小伸长量,根据测量结果计算钢丝的杨氏弹性模量。     

激光干涉法测量弹性模量

从光的干涉原理出发，讨论了金属丝弹性模量的光电测量方法．设计了激光干涉法测量长度微变量的测量装置，并介绍了测量原理，给出了动镜移动方向判别电路．     

扬声器纸盆材料动态弹性模量的新测量方法

本文从理论上对末端有负载的臂梁的自由振动频率进行了计算，并采用新的激振和拾振装置，建立一种扬声器纸盆材料的动态弹性模量的新测量方法，测量了若干纸盆试样，得出典型的幅频响应曲线，并对实验结果进行了分析。     

Determination of elastic modulus of a beam by using electronic speckle pattern interferometry

This paper proposes a sonic resonance test for an elastic modulus measurement which is based on the electronic speckle pattern interferometry. Previous measurement technique of elastic constant has the limitation of application for thin film or polymer material because contact to specimen affects the result. It has been developed as a non-contact optical measurement technique which can visualize resonance vibration mode shapes with whole field. The maximum vibration amplitude at each vibration mode shape is a clue to find the resonance frequencies. The dynamic elastic constant of test material can be easily determined from vibration of a beam equation using the measured resonance frequencies. The proposed technique is able to give high accurate elastic modulus of materials through a simple experimental set-up and analysis. The experimental result also compared to the theoretical result.     

对动力学法测定材料弹性模量实验的研究

简要分析了动力学法测定材料弹性模量实验在理论推导中存在的困难,讨论了实验中悬丝的材料、直径等影响因素,并提出相关建议;同时对利用李萨如图形判断共振频率的方法做了介绍和说明.     

基于弹性模量检测骨疲劳的超声导波方法研究

研究早期诊断骨疲劳的方法是当前骨质评价方面的研究热点之一. 本文对不同弹性模量下长骨中超声导波的传播特性进行了理论分析和仿真研究.首先, 通过数值计算得到导波在管状长骨中的理论解析解.然后对管状长骨进行了时域有限差分(FDTD) 仿真, 并验证了它与理论解析解的一致性, 同时得到长骨中不同模式导波群速度、 中心频率和衰减与弹性模量的关系.研究结果表明各个导波模式的群速度和中心频率均随弹性模量的增加而增加, 而衰减随弹性模量的增加而减小.说明超声导波的传播特性参量可以反映长骨弹性模量的变化, 从而为长骨的早期疲劳诊断提供理论依据.     

横向各向同性固体材料中含定向非均匀体的有效弹性模量

针对 含定向非均匀体的横向各向同性复合材料(即TI介质), 采用球形有效体散射等效的方法, 根据TI材料下的D, N_ij表达式, 对横向各向同性条件下Eshelby 张量的积分通用表达式进行化简, 推导出了复合材料的具有横向各向同性特性的有效弹性模量的表达式, 并依此进行了数值分析. 计算结果表明: 利用本方法计算的有效模量随非均匀体含量的增大而减小; 定向排列的非均匀体影响横向各向同性介质的固有各向异性, 水平指向的非均匀体会增大材料的横向各向同性, 模拟结果对评价含非均匀体各向异性介质的特征具有指导意义.