共查询到20条相似文献,搜索用时 171 毫秒
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JJG145-2007《摆锤式冲击试验机检定规程》于2008年实施至今,笔者对规程中的两种检定方法有一些看法,和大家探讨一下。
JJG145-2007中提出直接检定和间接检定两种方法。直接检定方法又称部件检定方法,是通过量具、力值标准等器具对试验机关键部件的检定,以保证冲击试验机的几何尺寸、摆锤力矩等满足规程的要求。 相似文献
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冲击试验标准ASTM E23—16b和EN 10045-1:1990,对于摆锤刀刃半径的要求分别为8mm和2 mm,为了研究这两种摆锤刀刃半径对于冲击试验结果的影响,依据这两个标准对SA508Gr.3Cl.2钢进行了系列温度冲击试验,并对断口形貌进行了观察。结果表明:摆锤刀刃半径对冲击吸收能量、侧膨胀值、剪切断面率以及韧脆转变温度等均有影响;总体上在韧性区和脆性区即低能量和高能量范围内,2 mm摆锤刀刃半径测得的数值小于8 mm摆锤刀刃半径测得的,在韧脆转变温度范围内,两者之间没有明显的大小关系。 相似文献
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本文详细地介绍了WE系列液压摆锤式万能材料试验机的检定、力值误差的分析和力值误差的消除方法。阐明了作为一名称职的力值计量检定人员,不但要会检定试验机,而且还要会对试验机所产生的误差进行综合细致地分析,将超差的试验机词修到合格的范围之内。 相似文献
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介绍了摆锤式冲击试验机的ASTM直接鉴定和间接鉴定方法。指出了直接鉴定部件的鉴定项目和要求,间接鉴定所用标准试样的制作要求、能量范围和鉴定结果的允许误差等。依据标准直接鉴定和间接鉴定均合格,则该试验机合格。 相似文献
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正JJG608-2014《悬臂梁式冲击试验机检定规程》(以下简称"新规程")经国家质检总局于2014年11月30日批准,自2014年5月30日起施行,代替JJG608-1989《悬臂梁式冲击试验机检定规程》(以下简称"旧规程")。旧规程制定将近25年,随着科学技术的发展和检测手段的提高,无论是在技术要求上还是在检测方法上,都已不能满足要求。同时,GB/T3808-2002《摆锤式冲击试验机的检验》、GB/T21189-2007《塑料简支梁、悬臂梁和拉伸冲击用摆锤式冲击试验机的检验》在此期间也进行了修订,因此,对旧规程进行修订非常必要。与旧 相似文献
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该文采用非接触式应变视频测量系统,开展了冷拉1860级钢绞线高温力学性能试验研究。基于试验测试的钢绞线高温应力-应变全过程曲线,建议了预应力钢结构用钢绞线的比例极限、弹性模量、名义屈服强度、断裂强度的高温折减系数以及高温应力-应变函数关系。试验结果表明,高强冷拉钢绞线高温下应力-应变全过程具有显著的应力强化阶段和颈缩阶段,1.25%应变下的高温名义屈服强度适用于高强冷拉钢绞线,钢绞线在高温下的捻度松弛效应对其高温力学性能存在影响。该研究成果进一步完善了预应力张拉钢结构用冷拉高强钢绞线高温下基本力学性能指标体系。 相似文献
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T. A. Siewert D. P. Vigliotti L. B. Dirling C. N. McCowan 《Journal of research of the National Institute of Standards and Technology》1999,104(6):557-565
Valid comparison of impact test energies reported by various organizations and over time depends on consistent performance of impact test machines. This paper investigates the influence of various specimen and test parameters on impact energies in the 1 J to 2 J range for both Charpy V-notch and Izod procedures, leading toward the identification of a suitable material for use in a program to verify machine performance. We investigated the influences on the absorbed energy of machine design, test material, specimen cross sectional area, and machine energy range. For comparison to published round robin data on common plastics, this study used some common metallic alloys, including those used in the international verification program for metals impact machines and in informal calibration programs of tensile machines. The alloys that were evaluated include AISI type 4340 steel, and five aluminum alloys: 2014-T6, 2024-T351, 2219-T87, 6061-T6, and 7075-T6. We found that certain metallic alloys have coefficients of variation comparable to those of the best plastics that are reported in the literature. Also, we found that the differences in absorbed energy between two designs of machines are smaller than the differences that can be attributed to the specimens alone. 相似文献
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液压静力压桩机的检定是保证其量值准确可靠的基础性工作,直接关系到施工机械的选择及桩基工程的质量,本文在介绍和分析液压静力压桩机的检定必要性、福建省的检定现状及形成该现状的原因的基础上,提出了加强液压静力压桩机检定工作的建议,以期为此项工作提供参考。 相似文献
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In Germany, structural fire design of masonry is carried out in a simplified way using tabulated minimum wall thicknesses depending on the loading level in fire. Against this background the procedure of structural fire design is shown briefly before two approaches for a more efficient verification of the fire resistance are explained. The first possibility is to determine the reduction factor for the design value of the actions in fire more precisely and thereby reduce the loading level. Secondly, a design methodology is presented which can be applied in case of masonry walls with low vertical load but a large load eccentricity at mid‐height of the wall. Finally, the verification of the fire resistance of masonry according to national technical approval is discussed with an explanation how to obtain the same loading level in fire if the design is based on DIN EN 1996‐3/NA as when it is based on DIN EN 1996‐1‐1/NA. 相似文献
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According to the German National Annex to DIN EN 1996‐3, a calculative verification of the bracing system may be omitted if, besides other requirements, an obviously sufficient number of sufficiently long shear walls is in place. If it is questionable whether a building complies with this requirement, a time‐consuming verification of the bracing system according to DIN EN 1996‐1‐1/NA is unavoidable. This article therefore presents a simplified verification method for the bracing system, which will prospectively be included in the next revision of DIN EN 1996‐3. The simplified bracing verification can already be used as a decision‐making aid to omit the calculative bracing verification according to DIN EN 1996‐1‐1/NA. 相似文献