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.     

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.     

激光超声无损检测

本文介绍自行研制的非接触式激光超声激励和检测系统，采用共焦式法布里—珀珞干涉仪实现对纳米量级微幅单次超声窄脉冲的检测，并应用该系统进行激光超声探伤及测定材料弹性常数的研究，实验结果表明激光超声技术是有效而且实用的     

Grating Recording for Moiré Testing

Experimental Techniques -     

A Pinned-end Fixture for Off-axis Testing

Experimental Techniques -     

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...     

An Adaptive Controller for Hybrid Fire Testing

Experimental Techniques - To experimentally assess the fire resistance of civil structures, testing whole structures is very costly but the standard tests on individual structural elements can...     

超塑胀形CCD光电检测技术

本文介绍了用 CCD 光电检测系统,测量超塑胀形高度随时间变化的规律 H(t).该系统具有测试精度高、稳定性好,和实时采集处理数据等优点.实测了 Ti-6Al-4V 圆形薄板等应变速率的 H(t)曲线.解决了反映超塑胀形过程的关键问题.     

Testing for nonlinear dependence in financial markets

This article addresses the question of improving the detection of nonlinear dependence by means of recently developed nonparametric tests. To this end a generalized version of BDS test and a new test based on symbolic dynamics are used on realizations from a well-known artificial market for which the dynamic equation governing the market is known. Comparisons with other tests for detecting nonlinearity are also provided. We show that the test based on symbolic dynamics outperforms other tests with the advantage that it depends only on one free parameter, namely the embedding dimension. This does not hold for other tests for nonlinearity.     

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。     

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．     

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.     

大型桥梁动力特性检测方法

本文提出了对运营中的大型桥梁在不影响效能的前提下检验大桥主要结构受力状态及性能的实用方法。重点介绍了斜拉桥与悬索桥索力的振动测量法，桥梁动力特性的测试、桥塔水平位移的激光测量等实验技术；给出了山东东营黄河大桥实测与计算的结果。     

二种岩石断裂韧度试样测试的稳定性分析

本文分析了 ISRM 采纳的两种具有人字形切槽的试样在测试过程中裂纹扩展的稳定性问题,计算了它们在不同加载条件和试验机刚度时各自的稳定性因子;指出对岩石等一类脆性材料,加载方式和试验机刚度对测试的稳定性有很大的影响;说明了这两种试样在稳定性方面的差异,并指出它们在稳定性上明显地优于普通直裂纹试样.     

Non-Contact Eddy Current Excitation Method for Vibration Testing

When a conductive material is subjected to a time changing magnetic field, eddy currents are induced in that structure. The eddy currents circulate inside the conductor resulting in a magnetic field that interacts with the applied field. The eddy current field is such that it opposes the change in flux resulting in a force between the source and conductor. The time changing magnetic field necessary to induce an electrometric force in the materials can be generated through a variety of different ways. In the present study, a permanent magnet will be mounted to the tip of an electromagnetic shaker such that the motion of the magnet relative to the structure will cause a time changing field and the formation of eddy currents. The actuator will be demonstrated to be beneficial due to its ability to apply actuation forces without contacting the structure. This study will show that the non-contact nature of the system eliminates mass loading and added stiffness which are downfalls of traditional excitation techniques. Additionally, it will be shown that the use of a non-contact device preserves the mode shapes of the structure, whereas a stinger results in distortions due to the added constraint. Using this concept, a model of the actuation system will be developed, allowing the beams response to be simulated. The actuation system will then be used to excite a cantilever beam to obtain the modal parameters without contacting the structure. The novel non-contact actuation system developed in this paper provides a new method performing vibration testing of on lightweight or flexible structures while preserving their dynamics.     

一种用于软材料测试的改进SHPB装置

本文提出了一种新的、用于测试橡胶、高弹体及高聚物软泡沫材料动态力学性能的SHPB改进装置。该装置取消了常见的入射杆而采用长杆弹直接撞击试件从而实现了持续的长时间加载，使得在相当大的应变率范围内试件的最大应变在一个加载过程中即可达到。配合该装置采用了瞬态响应优良、分辨率良好的光电式位移测试系统来测量试件的变形；为记录微弱的应变信号，在透射杆中使用了半导体应变片。本方案克服了传统SHPB在测试软材料时由于子弹长度限制带来的加载幅度不足及由于阻抗失配导致的应变信号微弱的困难；与采用高聚物杆的SHPB改进方案相比，本方案的测试结果也更为可靠。在试验装置中还运用了加载整形技术以改善试件中的应力均匀性。从测试结果看，该装置能有效地实现大变形范围、近似恒应变率持续加载以及相应的微弱应变信号的测量。     

人体平衡功能测试仪及定量指标研究

本文介绍了人体平衡功能测试仪的构造,工作原理及标定.同时应用概率统计原理对仪器测试数据和前庭功能试验的眼震时间进行相关分析。两种数据有良好的相关性,获得了人体平衡功能定量指标.     

Power-Flow-Based Stabilization for Adaptive Feedforward Filters in Hybrid Testing

Experimental Techniques - Real-time hybrid testing is a technology which allows the coupling of simulations and component tests in order to simulate complex system dynamics. Delays and time lags...