利用LabVIEW实现机械式万能试验机的智能化

传统机械式、液压万能试验机的实验分析能力有限，只能测得一些基本的实验数据，已经不适应现代化测试的需求。以低碳钢拉伸实验为例，利用LabVIEW软件对传统机械式万能试验机的拉伸实验进行了数字化改造，使试验机上测量的数据可以在计算机上实时显示、分析和处理。通过实验表明，该方法具有较好的适用性。     

Analysis and mechanical properties characterization of operated gas main elbow with hydrogen assisted large-scale delamination

The pipe elbows with hydrogen assisted large-scale delamination revealed in 40-years operated lateral pipelines located behind the compressor station were investigated. The crack on the external surface of the pipe elbow above the delamination was observed. The causes of the material degradation were studied by non-destructive testing using ultrasound thickness meter, microstructure observing, hydrostatic pressure testing, and mechanical properties characterization. The degradation degree of the pipe elbow steel was higher than of the straight pipe steel regardless of a section was tensioned or compressed. Basing on the tensile tests carried out on the cylindrical standard smooth and proposed circular notched specimens it was established that the plasticity of the operated steel could be measured correctly only on the specimens with a notch due to localisation of deformation in the cross section. The limitations in using elongation and reduction in area for characterization of plasticity of the pipe steel with extensive delamination were established. A special short transverse specimen for impact toughness measurement of pipelines steels was designed, fracture plane in which was parallel to the delamination plane. The extremely low KCV values were obtained under designed specimens testing, which correctly characterized brittle fracture resistance of material along structure fibers and a sensitivity of pipe steel to delamination as well. The two stages of in-service degradation of metal, deformation aging and multiple damaging, were analysed, and two substages of the second one were distinguished: dissipated disoriented damaging and damaging oriented in rolling direction.     

AN INVESTIGATION OF FATIGUE CRACK GROWTH IN A DUCTILE MATERIAL AT HIGH GROWTH RATES

Abstract— Investigations into tearing-fatigue have been performed using three point bend specimens made of mild steel. A computer controlled testing machine was used which could maintain constant cyclic displacement ranges, or constant cyclic energy input ranges, and hence provide a range of crack tip driving force conditions. Fatigue crack growth rates were measured and compared with the predictions of a model based on the linear summation and non-interaction of fatigue and ductile tearing growth rates. The effects of fatigue crack growth on monotonic crack growth resistance properties were investigated. It is concluded that there is no significant interaction between these two crack propagation mechanisms in this steel. Crack growth rate equations governing propagation in the tearing-fatigue regime are given.     

气波制冷机实时压力测试系统的开发

本文设计并开发了一套微机测试系统，实现了对气波制冷机接受管中瞬间变化的压力数值的实时测量，真实地反映了压力值，同时排除了现场的一些干扰信号，准确地表达了管中激波能量被削弱后的压力变化情况。     

铜基面抗拔摩擦摆支座的力学性能研究

为克服现有摩擦摆支座聚四氟乙烯（TEFLON）摩擦面承压能力低和缺乏竖向抗拔功能的不足,对课题组的专利产品—竖向抗拔摩擦摆支座进行了力学性能研究。论文首先介绍了支座的基本构造,并建立了支座的理论模型。为验证理论模型的合理性,设计了竖向承载力3000kN铜基面的摩擦摆支座,并对其进行试验研究。试验测定了竖向抗拔摩擦摆支座滑动面间的摩擦系数,考察了竖向压力和滑移速度对摩擦系数与滞回性能的影响。结果表明：铜基面摩擦摆支座在正弦简谐激励作用下的滞回曲线为平行四边形,与传统摩擦摆支座的滞回曲线具有相同的特征,呈刚塑性;铜基摩擦摆支座的摩擦系数的平均值在0.096-0.109间;滞回曲线的测试结果与数值模拟数据吻合较好,验证了理论模型的合理性。     

缓冲材料动态压缩试验的虚拟仪器设计

基于虚拟仪器思想．用VC 开发出了材料缓冲特性测试虚拟仪器系统。系统使用搜索技术，能可靠采集显示瞬时冲击信号；使用多种数字滤波技术能有效去除信号中的噪声，采取多种曲线拟合技术以得到各种描述材料缓冲特性的曲线。并以各种方式显示之。采用曲线位图转换存储技术抓取曲线图形。以拷贝到文本文件中；能自动按要求模板生成实验报告；采用文件自动管理技术管理数据文件．提高了它的可操作性。     

Failure analysis of forged and induction hardened steel cold work rolls

The premature failure of two forged and induction hardened low alloy steel work rolls used for cold rolling of high and medium carbon steel was investigated. Microhardness profiles indicated that the values of the effective induction hardening depth for both rolls are below the user's requirement. Tensile testing results of the core of the rolls indicated that the tensile and yield strengths are also below the manufacturer's requirements, the latter being 50% below the minimum requirements. The microstructure of the spalling surface presented tempered martensite, dispersed chromium carbides and spheroidised pearlite. The presence of spheroidised pearlite may have promoted the sub-superficial nucleation of rolling contact fatigue cracks. The heat-treatment schedule should be optimised in order to increase the depth of the hardening layer and the mechanical properties of the core, so that the contact fatigue life of the rolls can be improved.     

制动系统气压传感器测试平台研究

为满足实际应用要求,设计一种新的制动系统气压传感器测试平台。该平台以DSP系统为核心,包括气压传感器、制动系统气压模拟装置、汽车气压仪表以及上位机。DSP接受上位机的实验指令后,气压传感器通过调理电路送给DSP系统板以实时测量当前实际气压值,并传递给上位机进行同步显示。测试结果表明:该平台人机界面友好,操作简单方便,可应用于气压仪表及气压传感器的参数测试、标定及相关的培训教育等领域。     

压力容器钢及其焊接接头高速冲击韧性研究

在自行设计的高速冲击韧性测试系统上 ,采用预制疲劳裂纹的标准Charpy冲击试样 ,测试了常用压力容器钢I6MnR及其焊接接头的动态冲击韧性 ,研究了高加载速率条件下材料的断裂韧性特征 ,分析了加载速度、接头匹配性质和试验温度对动态冲击韧性的影响。研究结果表明 :焊缝金属对冲击加载速度最敏感 ,热影响区次之 ;焊接接头的匹配性质对冲击断裂韧性有较大的影响     

包装件压力试验机计算机测控系统

针对YE-50包装件压力试验机落后的测控系统，提出一种基于压力和位移闭环控制的计算机测控系统。根据测得的压力、位移和设定值，通过模糊控制输出驱动伺服阀实现了压力试验时的恒速控制和堆码试验时的恒力控制。并实时显示力——位移及应力——应变曲线。文中还对模糊控制器的实验整定方法进行了探讨。     

A/D Controller for Acquisitions of Signals with Different Sampling Periods

Efficient data acquisitions from analog signals of very different bandwidths require that each analog signal be sampled at a different rate. This paper proposes an A/D controller which has been implemented on an Analogic 5800 data acquisition system. The host computer is a PDP 11/45 with a DR11-C interface (see Fig. 1). Essentially, this programmable controller sorts out the sequencing of eight different analog channels. The sampling rate of each channel is independently set by software from 10 to 255 ps in I-its increments. Once the controller is programmed, it will control the A/D itself. The host computer programs the controller according to the user's instructions. The sampling rate of each analog channel may be independently set by software from 10 to 250 ps. Then the controller sets out the appropriate sequencing of the data collections on the analog channels, sorts out conflicts, and sees that information is stored properly in the host computer.     

圆光栅测角仪的研制

介绍一台高精度、自动化的动态测量角度仪器。该仪器采用了高精度的回转空气轴系和多测量头的均化技术,减小了基准制造误差对系统精度的影响,采用了计算机系统控制测量过程、数据处理,实现了自动化测量。     

Measurement systems for determining formwork pressure of highly-flowable concrete

This paper offers recommendations regarding test set-ups and measurement systems that can be used for laboratory evaluation and field testing of lateral pressure exerted by flowable concrete and self-consolidating concrete (SCC). Test results indicate that pressure sensors placed flush with the inner surface of the formwork can be used to assess the lateral pressure exerted by plastic concrete. The pore-water pressure resulting from the fluid phase of concrete can be evaluated using pore-water pressure sensors similar to the ones employed in soil mechanics. The sensors can be attached at different heights onto rigid formwork system to monitor changes in pressure with time.Sono-tubes made of cardboard are found not to be suitable for monitoring concrete pressure variations because of their flexibility which leads to erroneous values. A pressure column was developed to evaluate lateral pressure and its variations with time exerted by fresh SCC for heights of up to 10 m. Another system consisting of strain gages welded onto steel anchored bars inserted in the formwork was tested and compared to the pressure transducers system.     

Development of small bulge fatigue testing technique using small disk‐type specimen

A new fatigue testing technique, the small bulge fatigue (SBF) test using a small disk‐type specimen with flat and concave surfaces, was developed in this study. In the technique, a cyclic oil pressure could be alternatively applied to both specimen surfaces at the frequency of 10 Hz. After some verification tests for the displacement and strain measurements, type 316 austenitic stainless steel specimens were subjected to a preliminary test using this newly developed testing technique. As a result, the SBF test results (S‐N curve) were in good agreement with those of conventional fatigue tests by defining fatigue life as the number of cycles to the sudden drop in oil pressure because of fracture.     

核电材料在模拟反应堆环境中应力腐蚀破裂测试技术与性能评价

简要介绍了采用慢应变速率试验，Ｕ型弯曲和Ｃ形环试验等技术，分别对８００合金，３０４和３１６及３１６Ｔｉ不锈钢Ａ５３３Ｂ压力容器用多在模拟核反应堆环境中的应力腐蚀破裂敏感性性进行的试验研究的一些主要结果；并结合电化学测试和表面膜俄歇电子能谱分析结果进行了讨论。     

Unexpected Thermal Fracture of a Ceramic Sensor

A ceramic substrate bonded to an electronic sensor was reported to crack during thermal testing between −46 and +71 °C. Initially, this was assumed to occur at high temperature because of the thermal expansion of a polymer pad under the sensor. However, further investigations indicated that fracture was also occurring at low temperature. This was surprising since the suspected cause of fracture was pressure exerted by the polymer pad under the ceramic. This polymer pad has a coefficient of thermal expansion much greater than any other component. Conventional wisdom suggests that this failure would happen only during expansion of the pad during high temperature phases of temperature cycling. Subsequent dynamic thermal analysis revealed that differential contraction of the steel clamp fasteners was causing pressure to be exerted on the ceramic during the initial phase of the cold cycle. In addition, lateral constraint of the polymer pad caused pressure to rise to counterintuitive levels. An alteration of the geometry of the pad proved to be the simplest and most economical solution. This was confirmed by subsequent testing.     

Bond of cement grouted reinforcing bars under constant radial pressure

A ribbed rebar or rock bolt, grouted with Portland cement is the most common type of reinforcement in geomechanical projects such as tunnels, rock slopes and foundations. Due to the frictional nature of the bond slip the normal stress acting on the rebar is the most important parameter controlling the bond capacity of the reinforcement. The more the confining stress, the higher would be the mobilized load bearing capacity of the system. To quantify this effect, series of laboratory tests were designed to study the effect of confining pressure on the bond capacity. A modified triaxial Hoek cell (usually used for testing the strength of rock samples under radial confining pressure) was used to facilitate application of a “constant radial confining pressure” to the grouted sample while pulling the bolt axially through the cement annulus. During test, axial load and displacement of the bolt as well as the radial dilation of the grout was recorded and stored in computer using a data acquisition system. The results show a non-linear relation between the increase of bond capacity and confining pressure. The radial dilation is quantified also as a function of confining pressure. A peak-residual behaviour is also a characteristic of these results which shows the importance of limiting the deformation of rock blocks to avoid entering into the post peak range of the reinforcement with low values of bond.     

Study on high-temperature naphthenic acid corrosion and erosion-corrosion of aluminized carbon steel

High-temperature naphthenic acid corrosion (NAC) and erosion-corrosion (NAEC) behaviors of pack-aluminized carbon steel have been investigated in laboratory to evaluate the resistance of aluminized layer to the NAC and NAEC. A field erosion-corrosion test of 700 days was also performed in an oil refinery. Parallel tests were carried out for carbon steel. It was found that the aluminized steel exhibited a better NAC resistance only at early testing stage than the carbon steel in high total-acid-number (TAN) environment. The NAC resistance degraded rapidly with increasing testing time, and became even worse than that of the carbon steel at final testing stage, accompanying a step-like or lamellar spallation in the aluminized layer. In low TAN environment, the aluminized steel exhibited a much better resistance to both the NAC and NAEC in comparison with the carbon steel. Similarly a good erosion-corrosion resistance was found for the aluminized steel in actual oil-refining environment although relatively serious erosion-corrosion attack simultaneously took place in the aluminized layer. Based on the above results, possible NAC and NAEC mechanisms for the aluminized steel are discussed.     

可穿戴计算机所处的人体振动环境研究

可穿戴计算机所提供的全新的人机交互模式，决定了人体环境即为其工作环境。人体在运动时会产生振动，可穿戴计算机长期在振动环境下使用，其电气性能与可穿戴性能都会受到影响。对走动和跑动两种状态下人体适于放置可穿戴计算机的部位所产生的振动进行了测试和评估。有5名男生参加了测试，被测部位包括人体的上臂、前胸、腹部、腰部和大腿，对每一被测部位在水平方向和竖直方向上产生的振动进行了测试。通过对测试数据在时域和频域上的分析，得到了人体振动环境的特征。