高强高性能混凝土强度的实测研究

本文通过研究高强高性能混凝土的特性,比较了回弹法、超声回弹综合法和钻芯法等检测方法在高强高性能混凝土结构检测中的优缺点及适用范围。并以实际工程为例,结合该工程超高、大悬臂的结构特点,详细分析了各检测方法在该特种结构中的可行性,最终确定采用高强回弹仪对其混凝土强度进行回弹法检测,并制定了相应的检测方案。依据现场实测强度,采用规范方法对其进行修正,并对修正值进行了统计分析,进而评定了该混凝土强度的可靠性,得出:该结构混凝土强度服从正态分布,且达到设计要求;采用高强回弹仪对其进行检测是有效可行的。本文对同类采用高强混凝土的型钢组合结构、大悬臂特种结构具有重要参考价值。     

混凝土强度测试新方法研究与试验

通过对规程[4、5]规定的混凝土强度测度局限性的讨论，提出了一种 新的测试方法，即超声平测－回弹综合法，本文对该方法的原理和操作步骤进行说明，并通过现场实验进行了验证，通过实测证明该方法使测试条件更加宽松，测量精度满足工程实用要求，具有较大的理论意义和实际意义。     

历史保护建筑砖材强度检测方法研究

该文采用无损检测方法测定历史保护建筑砖材强度,利用回弹法、超声法以及超声回弹综合法对人工砖进行检测,经过回归分析建立历史保护建筑人工砖强度计算公式,并对历史保护建筑物所在区域获取的具有相同损伤状态的人工砖进行校核检验。研究表明:所得经验公式可用于相同类型的历史保护建筑砖砌体结构的检测,且超声回弹综合法比单纯的用回弹法或者超声法测得结果精确的多,最后提出了适用于历史保护建筑砖结构的检测方法,研究结果具有实用价值。     

关于超声回弹综合法检测混凝土强度技术的应用研究

随着我国社会经济建设的快速发展,水利行业管理日趋完善,水利工程施工质量的验收逐渐由科学的检测数据来判断,例如采用超声回弹综合法来检测混凝土的强度。本文通过对超生回弹综合法的概念及检测原理的介绍,并结合水利工程应用实例来对混凝土强度的检测进行深入的探讨分析,供类似工程参考与借鉴。     

建筑混凝土材料强度检测的技术分析

该文通过举例和对比分析法对建筑工程中的混凝土强度关键检测技术进行分析,包括回弹检测技术、超声回弹检测技术、拔出检测技术以及钻芯检测技术。经研究发现,通过检测技术的合理选择与应用,可以保证混凝土的强度检测质量。希望通过分析,可以为建筑工程混凝土强度检测质量的提升和整体工程设计与建设提供科学参考。     

钻芯法检测混凝土强度技术规程的应用

采用钻芯法检测混凝土强度，一定要充分注意芯样的钻取、芯样的加工、芯样试件的试验等各个环节，尽量避免这些因素影响钻芯法检测结构混凝土强度，在规范操作、减小外界影响前提下，进一步提高钻芯法检测精度，真正发挥钻芯法的检测作用。     

试论混凝土无损检测技术及其应用

随着社会科技的进步，随着人们生活需求的提高，对各类建筑设施质量的要求越来越高，因此，作为重要的建筑材料，混凝土在各种土木建筑等工程中得到越来越广泛的应用。混凝土无损检测技术在混凝土的质量保证方面起着不容忽视的作用，是建筑结构安全性能的重要保障。结合各种相关资料和多年工作经验，本文中笔者重点介绍了回弹法、超声波法、垂直反射法、地质雷达探测法以及钻芯法等混凝土无损检测技术及其应用。     

力-位移分控多点成形新工艺及其回弹控制机理

目的对比研究力-位移分控多点弯曲成形的受力和变形特点,揭示力-位移分控多点成形技术改善成形质量的机理。方法首先设计制造出采用力-位移分控多点成形原理成形的实验装置,并进行圆柱面的实际成形,比较不同成形模式下所获得成形制件的差异,然后采用理论分析和数值模拟等手段,分析对比不同成形模式的受力与变形条件,探讨不同成形模式下的变形特点与规律。结果从理论上给出了力-位移分控多点成形能有效减小回弹、消除"直边效应"的力学原理,指出了力-位移分控多点成形技术减小回弹的根本原因在于法向约束力的作用,且回弹减小量与法向约束力的大小成正比,并通过数值模拟,从应力和应变分布、支反力变化等方面予以了验证。结论力-位移分控多点成形从本质上改变了板材的受力和变形条件,能有效提升成形质量。     

对当前混凝土检测中常见问题及解决对策的探讨

混凝土质量决定着建筑工程的质量，对建筑工程混凝土结构是否牢固、是否耐用起着举足轻重的作用。所以对混凝土进行质量检测是保障建筑工程质量的关键环节。如果在混凝土质量检测中存在纰漏，马虎大意，就导致整个建筑工程难以进行下去。纵观当前混凝土检测，有严格标准和先进的方法，例如回弹法、超声波法、拔出法、钻芯法等科学方法，但在检测过程中仍存在问题。本文针对混凝土检测中常见问题，提出了解决思路和解决对策。     

回弹法检测潮湿或浸水混凝土强度的研究

回弹法检测混凝土强度时经常会遇到表面潮湿或浸水混凝土，因表面潮湿或浸水混凝土表面硬度降低，采用回弹法对潮湿或浸水的混凝土进行强度检测容易产生误判，必须进行修正。通过对同一标号的干湿混凝土现场检测，所得数据进行二元对比回归分析，提出了潮湿或浸水混凝土回弹法测强的修正方法，并建立精度满足要求的回弹法检测潮湿混凝土的强度曲线方程，可全面反映混凝土强度。     

An Assessment of the Double-Notch Shear Test for Interlaminar Shear Characterization of a Unidirectional Graphite/Epoxy under Static and Fatigue Loading

This research explores a modified testing technique for measuring interlaminar shear properties of orthotropic composite materials. An existing test method (double-notched test method) is examined here to characterize the interlaminar shear properties (strength and fatigue life) of a unidirectional ply under both static and fatigue loading conditions. No complicated fixture is required for the testing method which is beneficial for fatigue testing of the materials. The testing method is verified by a finite element technique where an optimized geometry for the specimen is found. AS4/3501-6 graphite/epoxy material is used in this study. The experimental results show that final failure occurs in the gage area for both static and fatigue loading conditions. Moreover, a reasonable amount of scatter for both the static strength and fatigue life is achieved.     

An Assessment of the Double-Notch Shear Test for Interlaminar Shear Characterization of a Unidirectional Graphite/Epoxy under Static and Fatigue Loading

This research explores a modified testing technique for measuring interlaminar shear properties of orthotropic composite materials. An existing test method (double-notched test method) is examined here to characterize the interlaminar shear properties (strength and fatigue life) of a unidirectional ply under both static and fatigue loading conditions. No complicated fixture is required for the testing method which is beneficial for fatigue testing of the materials. The testing method is verified by a finite element technique where an optimized geometry for the specimen is found. AS4/3501-6 graphite/epoxy material is used in this study. The experimental results show that final failure occurs in the gage area for both static and fatigue loading conditions. Moreover, a reasonable amount of scatter for both the static strength and fatigue life is achieved.     

球压法在线评价脆性材料的强度特性和残余应力

针对接触应力和压痕临界载荷的应力分布,通过应力梯度效应讨论分析了产生球压裂纹中的几个传统强度理论无法解释的问题.利用均强度准则提出了一种脆性材料局部强度和表面残余应力的压痕测试方法,并建立了一种简便的强度保证试验技术,对脆性构件的非破坏性能评价有实用意义.     

A method for testing the mechanical strength and kinetic features of fracture of lacquer coatings in seawater

A method for testing lacquer coatings in seawater is developed. This method enables one to predict the cohesion and adhesion strength of these coatings under conditions close to operating. The mechanical strength of the coatings is estimated with the help of a dimensionless parameter. Within the framework of the proposed testing method, one can also investigate the kinetic properties and other characteristics of fracture of lacquer coatings by using an optical technique and photography.Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 29, No. 6, pp. 108–110, November–December, 1993.     

硅片键合强度测试系统研究

对现有的几种硅片键合强度测试方法进行总结。在裂纹传播扩散法测试机理分析的基础上,提出了测试系统需要得到的参数和功能,采用模块化设计思想,对测试系统中的精密定位、显微视觉、红外测试和控制系统等关键技术分别研究,最后将单元技术集成,研制成功测试系统样机,通过对多个键合硅片强度测试对比实验,证明了该系统的有效性。     

The spalling of long bars as a reliable method of measuring the dynamic tensile strength of ceramics

An analysis of the spall bar test as a reliable method of determining the dynamic tensile strength of brittle materials is presented. The method is based on the propagation and reflection of elastic waves in bars. Failure occurs when compressive waves are reflected into tensile ones on reaching a free end. The study analyses the hypotheses needed to obtain the true tensile strength with this experimental technique, referring to the requirements of the material and of the experimental procedure. The analysis is complemented with numerical simulations of the testing procedure. The correct way to determine the true dynamic tensile strength of ceramic materials is outlined. Finally, the results of tests of some ceramic materials, three different aluminium oxides, an alumina reinforced with zirconia, silicon carbide and boron carbide are presented.     

A simple method for measuring tensile and shear bond strength of ceramic-ceramic and metal-ceramic joining

A simple method for measuring the ceramic-ceramic and metal-ceramic bond strength was presented, by which uniaxial tensile stress normal to the interface or shear stress in the interface can be produced using uniaxial compression load on a cross-bonded sample. Both tensile and shear bond strength were obtained by this testing technique for Ti₃SiC₂–TiO₂ and Ti₃SiC₂–Al₂O₃ composite as well as for glued steel samples, respectively. The novel method provided a solution for determining bond strength in solid (especially brittle) materials, and it is also demonstrated as a useful method for evaluating the tensile and shear strength of various glues. Electronic Publication     

A Distribution-Free Bayesian Approach for Determining the Joint Probability of Failure of Materials Subject to Multiple Proof Loads

Survival of manufacturing materials or component parts may depend on two or more variables, and yet joint strength tests can be difficult to perform. For many such materials, multiple strength properties can be estimated only using destructive testing. This problem gives rise to a technique called proof loading—stressing units up to a prescribed load, destroying only the weaker units, and leaving the survivors for further tests. We propose a distribution-free Bayesian approach for estimating the probability of joint failure under two proof loads. Our method does not assume that proof-load survivors are undamaged.     

Tensile properties of VGCF reinforced carbon composites

Carbon composites based on vapor grown carbon fibers prepared by a fixed catalyst method were fabricated using a pitch infiltration technique. The composites have both unidirectional and bi-directional fiber reinforcement, and different fiber volume fractions ranging from 25% to 56%. Specimens were prepared from these composites for tensile testing at room temperature, and tensile modulus and strength were determined. The composite modulus was then used to estimate the fiber modulus.     

基于连续球压痕法的45钢强度与韧性测试研究

为研究在役设备的材料强度与韧性测试评价问题,针对工程中常用材料45钢,采用连续球压痕方法,获取了材料的屈服强度、抗拉强度与断裂韧性,通过与常规力学性能试验结果比较,对该方法的可靠性进行了验证。通过研究球压头下压产生的塑性功,与冲击启裂能及断裂韧性之间的关联关系,建立基于仪器化球压痕测试技术的冲击韧性估算评估方法。试验结果表明,利用连续球压痕方法获取的屈服强度、抗拉强度与实际结果的偏差均小于10%,断裂韧性值与试验结果的偏差为12.3%,计算结果在试验值偏差数据范围内。利用连续球压痕技术,建立的断裂韧性与冲击韧性之间的关联公式,所预测的冲击韧性结果与仪器化冲击试验值具有较好的一致性,为在役设备材料的韧性快速评价提供了有效的测试方法。