羽毛球风洞的设计与应用

本文根据空气动力学基本原理,对羽毛球的空气动力作了分析研究。设计了为评定羽毛球质量所需的羽毛球风洞。本文还提出一种羽毛球的风洞试验结果与运动员经验评定羽毛球质量的结果进行相关的方法。实践证明,该风洞在评定羽毛球质量方面,取得了十分满意的结果。     

冲击拉伸实验装置的研制及其试验研究

材料动力学试验技术远比准静态力学中的复杂,为了模拟各种速率的冲击加载过程,试验装置设计就成为关键问题之一.特别是针对材料动态拉伸性能的测试,目前的冲击拉伸装置还没有统一标准,因此本文基于一维弹性应力波原理设计了一套双气室间接杆-杆型冲击拉伸试验装置.该装置采用了双气室对称布置的方式,通过气体转换器实现气路的转换,克服了现有气动式冲击拉伸设备结构复杂、密封要求严格的缺点.本文利用该装置对2A12T4铝合金试件的冲击拉伸性能进行了测试,并数值分析了应力波在杆系和试件中的传播效应.通过试验测试和数值分析论证了该冲击拉伸装置实验的可靠性和设计的合理性.     

Nanomechanical Testing of Gum Metal

“Gum Metal” is a newly developed β-Ti alloy that, in the cold-worked condition, has exceptional elastic elongation and high strength. The available evidence suggests that Gum Metal does not yield until the applied stress approaches the ideal strength, and then deforms by mechanisms that do not involve conventional crystal dislocations. To study its behavior, submicron-sized pillars of solution-treated and cold-worked Gum Metal were compressed in situ in a quantitative compression stage in a transmission electron microscope. Solution-treated specimens and half of the cold-worked specimens exhibited essentially monotonic hardening during compression, but with serrated load-deflection curves that included periodic partial relaxations of the stress. The other cold-worked specimens exhibited pronounced shear instability. These samples deformed by a stick-slip motion along a well-defined shear plane, with a serrated load-deflection curve demonstrating partial stress relaxation at each sliding event. The pattern of deformation is consistent with prior work showing deformation by the formation and growth of shear bands and faults in a matrix that is densely decorated with defects.     

人体头发的摩擦特性实验研究

采用微观摩擦磨损试验机对受损、干性和油性头发的摩擦系数及其发根和发稍的摩擦系数进行测试;通过扫描电子显微镜分析3种不同发质头发发根和发梢的表面形貌.结果表明:受损、干性和油性头发发根部位的平均摩擦系数分别为0.133、0.124和0.120,发梢部位的平均摩擦系数分别为0.151、0.138和0.136,摩擦系数从高到低依次为受损头发＞干性头发＞油性头发;受损头发的摩擦系数比自然头发高;干性头发和油性头发的摩擦系数相差不大;发根部位的摩擦系数比发稍部位低.头发品质和受损程度是头发摩擦特性差异的主要因素.     

实时子结构实验的研究进展

如果结构的非线性或不确定性仅集中于结构的某一部分,则可仅把这一部分取出来进行实验,其余部分采用数值模型予以模拟,这就是所谓的子结构实验技术。如果实验子结构的反力与加载速率有关,就必须采用实时加载的方式才能获得可靠的实验结果。由于试件性能的速度相关性和实验加载的实时性,使得实时子结构实验在逐步积分算法、实验系统的加载控制和实验系统累积误差等方面比拟动力实验更加复杂。本文介绍实时子结构实验的研究进展,并指出有待进一步研究的问题。     

人工髋、膝关节磨损测试标准及模拟试验机研究进展

髋膝关节植入物假体在体内发生摩擦磨损进而造成骨溶解、无菌松动是导致其失效的重要原因之一. 人工髋膝关节磨损试验是对假体材料、设计和加工进行评价的重要形式. 天然髋膝关节承受的运动和载荷十分复杂,研究天然关节在各种行为下的受力和运动范围,并利用专门的髋膝关节模拟器来进行试验和评价,有助于人工关节的设计和耐磨关节材料的发展. 本文中整理了天然髋膝关节的运动范围及载荷,对比了人工髋膝关节假体磨损的国内外标准,总结了主流髋膝关节模拟试验机的结构及主要技术参数,为我国关节行业的研究者提供参考.      

Improvised Sliding-Wear Testing Device

Experimental Techniques -     

Structural Testing TAC Meeting

Experimental Techniques -     

新型小载荷冲击磨损试验机的研制及其实验研究

设计并研制出新型小载荷冲击磨损试验机,介绍了该试验机的工作原理、结构及其主要技术参数,并采用所研制的试验机对TC4钛合金进行了8个不同周次的3组冲击磨损试验.结果表明:TC4钛合金的冲击坑形貌规整,具有明显的表面特征和累计损伤特征;在相同试验条件下试验结果的重现性较好,数据最大误差小于6%;试验机所加载荷稳定,长时运行无过流过温现象,能够满足小载荷冲击磨损试验的要求.     

Dynamic Tensile Testing of Soft Materials

Determination of dynamic tensile response of soft materials has been a challenge because of experimental difficulties. Split Hopkinson tension bar (SHTB) is a commonly used device for the characterization of high-rate tensile behavior of engineering materials. However, when the specimen is soft, it is challenging to design the necessary grips, to measure the weak transmitted signals, and for the specimen to achieve dynamic stress equilibrium. In this work, we modified the SHTB on the loading pulse, the equilibrium-monitoring system, and the specimen geometry. The results obtained using this modified device to characterize a soft rubber indicate that the specimen deforms under dynamic stress equilibrium at a nearly constant strain rate. Axial and radial inertia effects commonly encountered in dynamic characterization of soft materials are also minimized.     

人体手部皮肤的摩擦特性实验研究

采用微观摩擦磨损试验机对20名男女志愿者双手不同部位的摩擦系数进行测试.结果表明:男性手背皮肤的摩擦系数比女性偏低(女性为0.48～0.49,男性为0.38～0.39);男、女手掌的摩擦系数相差不大(女性为0.60～0.67,男性为0.62～0.70);男、女指纹的摩擦系数比较接近(女性为0.78～0.65,男性为0.77～0.68);男、女指甲的摩擦系数分别为女性0.25～0.21,男性0.23～0.21.在人体手部的手背、手掌、指纹和指甲4个部位中,摩擦系数的高低依次为指纹＞手掌＞手背＞指甲.     

Testing of glass fiber coalescing filters

Experimental Techniques - The paper presents an experimental study of coalescing filters for separating oil from compressed air in industrial systems. A test bench for measuring filter efficiency...     

微构件材料力学性能测试方法

随着MEMS的商业化进程,微构件材料力学性能的研究成为越来越重要的一个课题。微小试件的制备、安装、夹持、微驱动、高分辨率的载荷和位移测量等技术问题都是对微构件材料力学性能测试的很大挑战,很多传统的测试方法和装置已经不再适用了。近十几年,国内外学者发展了一些微构件材料力学性能的研究方法,来测量微构件的弹性模量、屈服强度、断裂强度、残余应力和疲劳强度等。本文从实验系统的集成度出发,将这些测试方法大致分为片外测试和片上测试两类。本文对单轴拉伸法、纳米压痕法、鼓膜法、微梁弯曲法和衬底曲率法等典型的片外测试方法和一些典型的片上测试方法进行了介绍,并比较了各自的优缺点。     

机械性能测试中图形的在线截取和重显

本文针对国产ＷＡＷ－１００万能试验机所带测试软件的不足，给出了采用ＴＳＲ技术对万能试验机在不同的试验情况下产生的变形曲线进行截取、储存，然后将截取的曲线在同一坐标系下进行重显的方法和程序，从而实现了对各种试验所测数据和曲线进行跟踪、比较和分析．     

小冲杆试验确定材料拉伸断后伸长率的研究

小冲杆试验技术可以近似无损地测试材料的力学性能.本文对几十种材料进行了小冲杆试验研究,对小冲杆试样的抽向挠度δ与拉伸断后伸长率A进行了经验关联.研究表明,对于试验中涉及的几十种材料,二者之间没有统一的线性相关公式,但可以按材料的杭拉强度和屈强比将材料分类,然后分别对δ和A进行线性关联.对于抗拉强度小于600MPa的材料...     

Microelectromechanical Systems for Nanomechanical Testing: Displacement- and Force-Controlled Tensile Testing with Feedback Control

Experimental Mechanics - Background: MEMS-based nanomechanical testing has received much interests. However, it remains challenging to perform displacement- and force-controlled nanomechanical...     

Testing techniques for restrained beam-columns

This paper describes a novel testing arrangement designed to investigate the load-deformation behavior of structural subassemblages composed of beams and beam-columns. The purpose of the tests is to investigate experimentally recently developed methods for analyzing structural frameworks. These new methods have placed greater emphasis on the behavior of the framework as a whole rather than as a collection of isolated members, and it has become necessary to study such combined behavior experimentally. The tests described allow this to be done in an efficient and practical manner and represent a step forward in the experimental study of structural behavior.The paper describes the purpose behind the tests, the testing method adopted and the errors and assumptions involved in the testing arrangement. Test results are only briefly presented.M. G. Lay, R. A. Aglietti and T. V. Galambos were formerly Research Instructor, Research Assistant and Research Associate Professor, respectively, at Civil Engineering Dept., Fritz Engineering Laboratory, Lehigh University, Bethlehem, Pa.Paper was presented at Second SESA International Congress on Experimental Mechanics held in Washington, D. C., on Sept. 28–Oct. 1, 1965.     

Problem of Vibration Testing of Space Structures

The results of numerical analysis of the parameters of the first-order synergistic effect are analyzed. They are formalized by means of the amplitude-phase-frequency characteristics of a space structure in absolute coordinates as applied to vibration-reliability problems. The synergistic factor is used to estimate quantitatively and qualitatively the synergistic effect of the vibration parameters of the housing on the vibration stability of the test structure __________ Translated from Prikladnaya Mekhanika, Vol. 41, No. 7, pp. 116–121, July 2005.     

Microelectromechanical Systems for Nanomechanical Testing: Electrostatic Actuation and Capacitive Sensing for High-Strain-Rate Testing

Experimental Mechanics - There have been relatively few studies on mechanical properties of nanomaterials under high strain rates, mainly due to the lack of capable nanomechanical testing devices....     

Testing methods for large aircraft

Some unique testing methods in connection with static-load application and associated data acquisition are described. The “free-flight” method of airplane static testing is covered as it applies to the current test program for the C-133 Cargomaster (300,000 lb gross weight). The loading and safety advantages of the “single-pressure concept” are discussed. Instrumentation provides for visual readout as well as IBM punch cards for records of deflection, cabin pressures, jack loads and up to a total of 2800 strain gage installations. Use of the “Electromec,” and safety methods for fuselages pressurized by air are discussed. Additional areas that are covered: hydrostatic-test methods and instrumentation; fail-safe development for pressurized cabins; and future of fatigue tests of a complete airplane.