首页 > 最新文献

Journal of Astm International最新文献

英文 中文
Flame Retardant Emissions from Spray Polyurethane Foam Insulation 喷涂聚氨酯泡沫隔热材料的阻燃排放物
Pub Date : 2017-02-01 DOI: 10.1520/STP158920150044
D. Poppendieck, M. Schlegel, A. Connor, A. Blickley
The desire to build more energy efficient homes in the United States has led to the expansion of the residential spray polyurethane foam (SPF) insulation industry. Upon application of SPF, reacting chemicals form expanding polyurethane foam that fills cracks and gaps, reducing infiltration and thermal conductivity of the building envelope. However, more information is being sought on chemical emissions from SPF to better understand occupant exposures and any potential impacts on health. The objective of this investigation was to investigate the emission of flame retardant tris (1-chloro-2-propyl) phosphate (TCPP) from SPF using both micro-chambers and a full scale residential test facility. Two high pressure, open cell foams and one high pressure, closed cell foam were tested using micro-chambers. After 100 hours, TCPP concentrations from the open cell samples were 100 times higher than TCPP concentrations from the closed cell SPF. TCPP emissions from open cell foam were found to correlate exponentially with temperature and vary with flow rate, indicating emission factors from SPF micro-chamber experiments may not directly predict TCPP concentrations in buildings without consideration of material mass transfer properties. Due to the use of TCPP in furniture, SPF has not previously been positively identified as a primary source of indoor TCPP concentrations in actual buildings. This research measured airborne TCPP concentrations in the furniture-free National Institute of Standards and Technology (NIST) Net Zero Energy Residential Test Facility (NZERTF) that contained 15 m of exposed, two-year-old, open cell SPF. The measured NZERTF TCPP emission rates were not directly predicted by emission factors from the micro-chamber measurements, which suggests a mass transfer-based modelling approach is needed for predicting TCPP concentrations from open cell SPF. More research is needed to determine how data from micro-chamber studies can be used to predict exposures of residential occupants to emissions from SPF foam.
在美国,建造更多节能住宅的愿望导致了住宅喷雾聚氨酯泡沫(SPF)保温行业的扩张。在使用SPF后,化学反应形成膨胀的聚氨酯泡沫,填充裂缝和空隙,减少建筑围护结构的渗透和导热性。然而,人们正在寻求更多关于SPF的化学物质排放的信息,以更好地了解居住者接触的化学物质及其对健康的潜在影响。本研究的目的是研究阻燃剂三(1-氯-2-丙基)磷酸盐(TCPP)从SPF的排放使用微室和全尺寸的住宅测试设施。使用微室测试了两种高压开孔泡沫和一种高压闭孔泡沫。100小时后,开放细胞样品的TCPP浓度比封闭细胞SPF的TCPP浓度高100倍。开孔泡沫的TCPP排放与温度呈指数相关,并随流量变化,这表明SPF微室实验的排放因子可能不能直接预测建筑物中TCPP的浓度,而不考虑材料的传质特性。由于家具中TCPP的使用,SPF以前没有被确定为实际建筑物中室内TCPP浓度的主要来源。本研究在无家具的美国国家标准与技术研究院(NIST)净零能耗住宅测试设施(NZERTF)中测量了空气中TCPP的浓度,该设施包含15米暴露的,两年的开放式SPF。测量的NZERTF TCPP发射率不能由微室测量的发射因子直接预测,这表明需要基于传质的建模方法来预测开孔SPF的TCPP浓度。需要更多的研究来确定如何使用微室研究的数据来预测住宅居住者对SPF泡沫排放物的暴露。
{"title":"Flame Retardant Emissions from Spray Polyurethane Foam Insulation","authors":"D. Poppendieck, M. Schlegel, A. Connor, A. Blickley","doi":"10.1520/STP158920150044","DOIUrl":"https://doi.org/10.1520/STP158920150044","url":null,"abstract":"The desire to build more energy efficient homes in the United States has led to the expansion of the residential spray polyurethane foam (SPF) insulation industry. Upon application of SPF, reacting chemicals form expanding polyurethane foam that fills cracks and gaps, reducing infiltration and thermal conductivity of the building envelope. However, more information is being sought on chemical emissions from SPF to better understand occupant exposures and any potential impacts on health. The objective of this investigation was to investigate the emission of flame retardant tris (1-chloro-2-propyl) phosphate (TCPP) from SPF using both micro-chambers and a full scale residential test facility. Two high pressure, open cell foams and one high pressure, closed cell foam were tested using micro-chambers. After 100 hours, TCPP concentrations from the open cell samples were 100 times higher than TCPP concentrations from the closed cell SPF. TCPP emissions from open cell foam were found to correlate exponentially with temperature and vary with flow rate, indicating emission factors from SPF micro-chamber experiments may not directly predict TCPP concentrations in buildings without consideration of material mass transfer properties. Due to the use of TCPP in furniture, SPF has not previously been positively identified as a primary source of indoor TCPP concentrations in actual buildings. This research measured airborne TCPP concentrations in the furniture-free National Institute of Standards and Technology (NIST) Net Zero Energy Residential Test Facility (NZERTF) that contained 15 m of exposed, two-year-old, open cell SPF. The measured NZERTF TCPP emission rates were not directly predicted by emission factors from the micro-chamber measurements, which suggests a mass transfer-based modelling approach is needed for predicting TCPP concentrations from open cell SPF. More research is needed to determine how data from micro-chamber studies can be used to predict exposures of residential occupants to emissions from SPF foam.","PeriodicalId":15057,"journal":{"name":"Journal of Astm International","volume":"75 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74152424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 13
Economic Impact of Improved Service-Life Prediction for Seams in Low-Slope EPDM Roofing 改进低坡度三元乙丙橡胶屋面接缝寿命预测的经济影响
Pub Date : 2014-10-05 DOI: 10.1520/STP158620140035
Douglas S Thomas
{"title":"Economic Impact of Improved Service-Life Prediction for Seams in Low-Slope EPDM Roofing","authors":"Douglas S Thomas","doi":"10.1520/STP158620140035","DOIUrl":"https://doi.org/10.1520/STP158620140035","url":null,"abstract":"","PeriodicalId":15057,"journal":{"name":"Journal of Astm International","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75823982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The Economics of Residential Fire Sprinklers and the Potential Impact of Recent Code Changes 住宅消防喷头的经济性和近期法规变化的潜在影响
Pub Date : 2014-10-05 DOI: 10.1520/STP158620140038
D. Butry
{"title":"The Economics of Residential Fire Sprinklers and the Potential Impact of Recent Code Changes","authors":"D. Butry","doi":"10.1520/STP158620140038","DOIUrl":"https://doi.org/10.1520/STP158620140038","url":null,"abstract":"","PeriodicalId":15057,"journal":{"name":"Journal of Astm International","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2014-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85576354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Roller Profile Development for an Axially Loaded, Single Row Spherical Roller Bearing in an Oscillating Application 振动应用中轴向加载单列球面滚子轴承的滚子轮廓发展
Pub Date : 2012-10-01 DOI: 10.1520/JAI103891
J. H. Cowles, C. Houle
Typically it is not recommended to use a single row spherical roller bearing in an application in which there are significant axial loads. The use of these bearings in a less than optimal customer application can be driven by the need for a high load capacity within a limited geometric envelope. Specialized roller profiles can be developed that eliminate high contact stresses on the roller ends that can lead to the premature failure of the bearing. In this paper, analytical results are presented for the roller to raceway contact stress of four different roller profiles with a given load applied to the bearing. The profiles considered are single transverse radius, double transverse radii, and optimized symmetric and asymmetric. The piecewise logarithmic profiles developed are applied to a barrel roller in this paper, but a generalized method is developed such that the profile could be applied to any type of roller—cylindrical, barrel, hourglass, or tapered. The analysis results for two of the profiles are validated by dynamic testing performed within RBC’s Corporate Test Laboratory on a three axis, hydraulic, computer controlled test rig. The bearing inner ring is oscillated while the bearing is subjected to simultaneous radial and axial loads. The control software allows the monitoring of radial displacement and bearing torque during testing. The test results correlate very well with the analytical results. The displacement and torque readouts are shown to predict the onset of raceway fatigue and spalling for one of the roller configurations before testing is complete and the bearing is disassembled.
通常不建议在有显著轴向载荷的应用中使用单列球面滚子轴承。在不太理想的客户应用中使用这些轴承可能是由于需要在有限的几何包络内提供高负载能力。可以开发专门的滚子轮廓,以消除滚子端可能导致轴承过早失效的高接触应力。在本文中,分析结果提出了滚子到滚道接触应力的四种不同的滚子轮廓与给定的载荷施加到轴承。考虑的轮廓有单横向半径、双横向半径以及优化的对称和非对称。本文将所建立的分段对数型线应用于筒状辊筒,但提出了一种广义的方法,使该型线可以应用于任何类型的辊筒——圆柱形、筒形、沙漏形或锥形。RBC公司测试实验室在三轴、液压、计算机控制的测试台上进行了动态测试,验证了两种剖面的分析结果。当轴承同时受到径向和轴向载荷时,轴承内圈振荡。控制软件允许在测试期间监测径向位移和轴承扭矩。试验结果与分析结果吻合得很好。在测试完成并拆卸轴承之前,显示的位移和扭矩读数可以预测其中一种滚子配置的滚道疲劳和剥落的开始。
{"title":"Roller Profile Development for an Axially Loaded, Single Row Spherical Roller Bearing in an Oscillating Application","authors":"J. H. Cowles, C. Houle","doi":"10.1520/JAI103891","DOIUrl":"https://doi.org/10.1520/JAI103891","url":null,"abstract":"Typically it is not recommended to use a single row spherical roller bearing in an application in which there are significant axial loads. The use of these bearings in a less than optimal customer application can be driven by the need for a high load capacity within a limited geometric envelope. Specialized roller profiles can be developed that eliminate high contact stresses on the roller ends that can lead to the premature failure of the bearing. In this paper, analytical results are presented for the roller to raceway contact stress of four different roller profiles with a given load applied to the bearing. The profiles considered are single transverse radius, double transverse radii, and optimized symmetric and asymmetric. The piecewise logarithmic profiles developed are applied to a barrel roller in this paper, but a generalized method is developed such that the profile could be applied to any type of roller—cylindrical, barrel, hourglass, or tapered. The analysis results for two of the profiles are validated by dynamic testing performed within RBC’s Corporate Test Laboratory on a three axis, hydraulic, computer controlled test rig. The bearing inner ring is oscillated while the bearing is subjected to simultaneous radial and axial loads. The control software allows the monitoring of radial displacement and bearing torque during testing. The test results correlate very well with the analytical results. The displacement and torque readouts are shown to predict the onset of raceway fatigue and spalling for one of the roller configurations before testing is complete and the bearing is disassembled.","PeriodicalId":15057,"journal":{"name":"Journal of Astm International","volume":"1 1","pages":"103891"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88222681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Mechanical Characteristics of Degraded Silicone Bonded Point Supports 降解硅树脂粘结点支架的机械特性
Pub Date : 2012-07-01 DOI: 10.1520/JAI104061
A. Hagl, A. Wolf, S. Dean
Tensile loading of bonded point supports is considered as the critical load case for adhesive material, e.g., silicone applied to such kinds of fixtures. From a durability point of view, the following defects of two-component adhesives are expected to have a significant impact on the response to this loading regime: the wrong mixing ratios of the adhesive components, inhomogeneous mixing due to insufficient or poor mechanical mixing procedures, load degradation of the adhesive bonding material, local degradations of the bonding, e.g., bubbles or poor adhesion. In order to investigate these aspects, different experimental approaches have been pursued. Regarding the mixing ratio aspect, material tests were performed with systematically varied mixing ratios for the analysis of the elastic and strength properties while for the other topics, tensile tests of bonded point supports were evaluated in detail. Cyclic tests of point supports in the tensile load regime were set up, differing in amplitudes and maximum peaks of the cycles, in order to analyze the impact of load histories on the mechanical characteristics of the specimens. For point supports subjected to monotonically increasing loads the qualitative assessment of the fracture surfaces revealed the existence and the potential impact of disturbances inside the bonding, such as bubbles or locally lacking adhesion, on the damage behavior and on related inferior mechanical performance. The main motivation for this kind of research is to improve confidence in the durability of bonded designs. Thus, our activities were focused on aspects which might affect durability from an application point of view, not from a purely academic one. Especially in Germany, the confidence of the authorities in this joining technique has to be strengthened by demonstrating a high degree of robustness in the application, and in view of the risk associated with potential in-field problems.
粘接点支撑的拉伸载荷被认为是粘接材料的关键载荷情况,例如应用于此类夹具的硅酮。从耐久性的角度来看,双组分胶粘剂的以下缺陷预计会对这种加载机制的响应产生重大影响:胶粘剂组分的混合比例错误,由于机械混合程序不充分或不佳而导致的混合不均匀,胶粘剂粘合材料的负载降解,粘合的局部降解,例如气泡或粘合不良。为了研究这些方面,人们采用了不同的实验方法。在混合比方面,系统地进行了不同混合比的材料试验,以分析弹性和强度性能,而在其他主题上,对粘结点支架的拉伸试验进行了详细评估。建立了点支架在拉伸载荷下的循环试验,不同的周期振幅和最大峰值,以分析载荷历史对试件力学特性的影响。对于单调递增载荷作用下的点支架,通过对断口表面的定性分析,揭示了粘接内部存在气泡或局部不粘接等扰动,并对其损伤行为和相关的较差力学性能产生潜在影响。这种研究的主要动机是提高对粘合设计耐久性的信心。因此,从应用的角度来看,我们的活动集中在可能影响耐久性的方面,而不是纯粹的学术角度。特别是在德国,考虑到与潜在的现场问题有关的风险,必须通过展示应用中的高度稳健性来加强当局对这种连接技术的信心。
{"title":"Mechanical Characteristics of Degraded Silicone Bonded Point Supports","authors":"A. Hagl, A. Wolf, S. Dean","doi":"10.1520/JAI104061","DOIUrl":"https://doi.org/10.1520/JAI104061","url":null,"abstract":"Tensile loading of bonded point supports is considered as the critical load case for adhesive material, e.g., silicone applied to such kinds of fixtures. From a durability point of view, the following defects of two-component adhesives are expected to have a significant impact on the response to this loading regime: the wrong mixing ratios of the adhesive components, inhomogeneous mixing due to insufficient or poor mechanical mixing procedures, load degradation of the adhesive bonding material, local degradations of the bonding, e.g., bubbles or poor adhesion. In order to investigate these aspects, different experimental approaches have been pursued. Regarding the mixing ratio aspect, material tests were performed with systematically varied mixing ratios for the analysis of the elastic and strength properties while for the other topics, tensile tests of bonded point supports were evaluated in detail. Cyclic tests of point supports in the tensile load regime were set up, differing in amplitudes and maximum peaks of the cycles, in order to analyze the impact of load histories on the mechanical characteristics of the specimens. For point supports subjected to monotonically increasing loads the qualitative assessment of the fracture surfaces revealed the existence and the potential impact of disturbances inside the bonding, such as bubbles or locally lacking adhesion, on the damage behavior and on related inferior mechanical performance. The main motivation for this kind of research is to improve confidence in the durability of bonded designs. Thus, our activities were focused on aspects which might affect durability from an application point of view, not from a purely academic one. Especially in Germany, the confidence of the authorities in this joining technique has to be strengthened by demonstrating a high degree of robustness in the application, and in view of the risk associated with potential in-field problems.","PeriodicalId":15057,"journal":{"name":"Journal of Astm International","volume":"8 1","pages":"104061"},"PeriodicalIF":0.0,"publicationDate":"2012-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82566921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
FEM Analysis of a DCP Implant on a Human Femoral Bone With a Fracture Gap 带骨折间隙的人股骨DCP假体的有限元分析
Pub Date : 2012-07-01 DOI: 10.1520/JAI103924
T. Fongsamootr, S. Bernard
Our research aims to determine the optimal screw configuration of a dynamic compressive plate (DCP) implant on a human femoral bone. The number of screws and the positioning are sensitive parameters of DCP implant stress repartition. Several previous studies have assessed the influence of thescrew configuration of a DCP implant. Using a realistic geometry of a human left femur and the finite element method (FEM), the calculations in those papers were based on a safe femoral bone. This study evaluates the influence of the application of a simulated fracture gap in the diaphyseal part on the stress repartition of the bone, plate, and screws. The main purpose is to complete the existing studies in order to provide surgeons with information on an optimal prosthesis screw configuration. The plate and screws were modeled and assembled on a cracked femoral bone. The hip region of the femur was loaded with vertical and horizontal forces. The femoral bone was cut into two parts because of the gap: the top part, close to thehip, and the bottom part, close to the knee. The FEM analysis shows that the stresses in screws located in the top part of the femoral bone had significantly increased, whereas the stresses on the plate and the bone had been reduced.
我们的研究旨在确定人类股骨上动态加压钢板(DCP)植入物的最佳螺钉配置。螺钉数量和定位是影响DCP种植体应力再分配的敏感参数。先前的一些研究已经评估了螺钉配置对DCP种植体的影响。利用人类左股骨的真实几何形状和有限元法(FEM),这些论文中的计算都是基于安全的股骨。本研究评估在骨干部分应用模拟骨折间隙对骨、钢板和螺钉应力再分配的影响。主要目的是完成现有的研究,以便为外科医生提供最佳假体螺钉配置的信息。钢板和螺钉在骨折的股骨上建模和组装。股骨髋部受到垂直和水平方向的作用力。因为有这个缺口,股骨被切成两部分:顶部靠近臀部,底部靠近膝盖。有限元分析表明,位于股骨顶部的螺钉的应力明显增加,而钢板和骨的应力有所降低。
{"title":"FEM Analysis of a DCP Implant on a Human Femoral Bone With a Fracture Gap","authors":"T. Fongsamootr, S. Bernard","doi":"10.1520/JAI103924","DOIUrl":"https://doi.org/10.1520/JAI103924","url":null,"abstract":"Our research aims to determine the optimal screw configuration of a dynamic compressive plate (DCP) implant on a human femoral bone. The number of screws and the positioning are sensitive parameters of DCP implant stress repartition. Several previous studies have assessed the influence of thescrew configuration of a DCP implant. Using a realistic geometry of a human left femur and the finite element method (FEM), the calculations in those papers were based on a safe femoral bone. This study evaluates the influence of the application of a simulated fracture gap in the diaphyseal part on the stress repartition of the bone, plate, and screws. The main purpose is to complete the existing studies in order to provide surgeons with information on an optimal prosthesis screw configuration. The plate and screws were modeled and assembled on a cracked femoral bone. The hip region of the femur was loaded with vertical and horizontal forces. The femoral bone was cut into two parts because of the gap: the top part, close to thehip, and the bottom part, close to the knee. The FEM analysis shows that the stresses in screws located in the top part of the femoral bone had significantly increased, whereas the stresses on the plate and the bone had been reduced.","PeriodicalId":15057,"journal":{"name":"Journal of Astm International","volume":"16 1","pages":"103924"},"PeriodicalIF":0.0,"publicationDate":"2012-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87253144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Fatigue Crack Closure in Residual Stress Bearing Materials 残余应力承载材料的疲劳裂纹闭合
Pub Date : 2012-07-01 DOI: 10.1520/JAI104071
M. R. Hill, Jihwi Kim, S. Daniewicz, S. Dean
During fatigue crack growth, the two opposing faces of a fatigue crack can make physical contact while unloading from a maximum level of cyclic load, so that the crack tip state at the minimum cyclic load depends on the host geometry, material properties, and loading history. Although significant work has been performed in order to examine the effects of crack face contact, often called crack closure, under variations of applied loading history, little work has been done to understand the details of crack closure in materials that contain bulk residual stress fields. For an elastic material, variations of applied load history create changes in the crack tip behavior that are directly related to the current levels of cyclic stress, with no effect of prior loading. For an elastic-plastic material, variations of the applied load history cause the crack tip behavior to depend on the current and former loading cycles, because of plastic deformation in the crack wake. In an elastic material with bulk residual stress, crack closure occurs because the strain fields locked into the material, which are the source of the residual stress, alter the shape of the crack faces, so that the details of closure depend on the residual stress field and crack geometry. Residual stresses might therefore affect fatigue crack growth in two distinct ways: first, by combining with applied loads to affect the stress intensity factor (at the current crack size), and second, by altering crack closure. We emphasize that the effect of bulk residual stresses on crack closure described here is an elastic effect, which distinguishes it from the more commonly discussed forms of closure, such as arise from plasticity or roughness. The paper describes a means to forecast crack closure due to bulk residual stress fields and assesses schemes to account for its effects on fatigue crack growth.
在疲劳裂纹扩展过程中,疲劳裂纹的两个相对面可以在最大循环载荷卸载时发生物理接触,因此在最小循环载荷下裂纹尖端的状态取决于宿主的几何形状、材料特性和加载历史。尽管为了检验裂纹面接触(通常称为裂纹闭合)在不同加载历史下的影响已经进行了大量的工作,但对于包含大块残余应力场的材料的裂纹闭合细节的了解却很少。对于弹性材料,施加载荷历史的变化会产生裂纹尖端行为的变化,这与当前的循环应力水平直接相关,而不受先前载荷的影响。对于弹塑性材料,由于裂纹尾迹中的塑性变形,施加载荷历史的变化导致裂纹尖端的行为取决于当前和以前的加载循环。在具有大量残余应力的弹性材料中,由于锁定在材料中的应变场(残余应力的来源)改变了裂纹面形状,因此裂纹闭合的细节取决于残余应力场和裂纹几何形状,从而导致裂纹闭合。因此,残余应力可能以两种不同的方式影响疲劳裂纹的扩展:第一,通过与施加的载荷结合来影响应力强度因子(在当前裂纹尺寸下),第二,通过改变裂纹闭合。我们强调,这里描述的体积残余应力对裂纹闭合的影响是一种弹性效应,这与更常见的讨论形式的闭合(如由塑性或粗糙度引起的闭合)区别开来。本文介绍了一种预测由于大块残余应力场而导致裂纹闭合的方法,并评估了考虑其对疲劳裂纹扩展影响的方案。
{"title":"Fatigue Crack Closure in Residual Stress Bearing Materials","authors":"M. R. Hill, Jihwi Kim, S. Daniewicz, S. Dean","doi":"10.1520/JAI104071","DOIUrl":"https://doi.org/10.1520/JAI104071","url":null,"abstract":"During fatigue crack growth, the two opposing faces of a fatigue crack can make physical contact while unloading from a maximum level of cyclic load, so that the crack tip state at the minimum cyclic load depends on the host geometry, material properties, and loading history. Although significant work has been performed in order to examine the effects of crack face contact, often called crack closure, under variations of applied loading history, little work has been done to understand the details of crack closure in materials that contain bulk residual stress fields. For an elastic material, variations of applied load history create changes in the crack tip behavior that are directly related to the current levels of cyclic stress, with no effect of prior loading. For an elastic-plastic material, variations of the applied load history cause the crack tip behavior to depend on the current and former loading cycles, because of plastic deformation in the crack wake. In an elastic material with bulk residual stress, crack closure occurs because the strain fields locked into the material, which are the source of the residual stress, alter the shape of the crack faces, so that the details of closure depend on the residual stress field and crack geometry. Residual stresses might therefore affect fatigue crack growth in two distinct ways: first, by combining with applied loads to affect the stress intensity factor (at the current crack size), and second, by altering crack closure. We emphasize that the effect of bulk residual stresses on crack closure described here is an elastic effect, which distinguishes it from the more commonly discussed forms of closure, such as arise from plasticity or roughness. The paper describes a means to forecast crack closure due to bulk residual stress fields and assesses schemes to account for its effects on fatigue crack growth.","PeriodicalId":15057,"journal":{"name":"Journal of Astm International","volume":"1 1","pages":"104071"},"PeriodicalIF":0.0,"publicationDate":"2012-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91210760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
Point Load Weight Functions for Semi-Elliptical Cracks in Finite Thickness Plate 有限厚板半椭圆裂纹的点荷载权重函数
Pub Date : 2012-07-01 DOI: 10.1520/JAI103962
Zhaoyu Jin, Xin Wang
This paper presents the application of the weight function method for the calculation of stress intensity factors for surface semi-elliptical cracks in finite thickness plates subjected to arbitrary two-dimensional stress fields. A new general mathematical form of point load weight function has been formulated by taking advantage of the knowledge of a few specific weight functions for two-dimensional planar cracks available in the literature and certain properties of the weight function in general. The existence of the generalized form of the weight function simplifies the determination of a specific weight function for specific crack configurations. The determination of a specific weight function is reduced to the determination of the parameters of the generalized weight function expression. These unknown parameters can be determined from reference stress intensity factor solutions. This method is used to derive the weight functions for semi-elliptical surface cracks in finite thickness plates. The derived weight functions are then validated against stress intensity factor solutions for several linear and non-linear two-dimensional stress distributions. The derived weight functions are particularly useful for the fatigue crack growth analysis of planar surface cracks subjected to fluctuating nonlinear stress fields resulting from surface treatment (shot peening), stress concentration, or welding (residual stress)
本文应用权函数法计算了有限厚度板在任意二维应力场作用下的表面半椭圆裂纹的应力强度因子。利用文献中关于二维平面裂纹的几个特定权函数的知识和权函数的一般性质,提出了一种新的点荷载权函数的一般数学形式。权函数广义形式的存在简化了对特定裂纹构型的权函数的确定。具体权函数的确定可简化为广义权函数表达式参数的确定。这些未知参数可由参考应力强度因子解确定。用该方法推导了有限厚度板中半椭圆表面裂纹的权函数。然后根据几种线性和非线性二维应力分布的应力强度因子解验证了导出的权重函数。导出的权函数对于受波动非线性应力场影响的平面表面裂纹的疲劳裂纹扩展分析特别有用,这些应力场是由表面处理(喷丸)、应力集中或焊接(残余应力)引起的。
{"title":"Point Load Weight Functions for Semi-Elliptical Cracks in Finite Thickness Plate","authors":"Zhaoyu Jin, Xin Wang","doi":"10.1520/JAI103962","DOIUrl":"https://doi.org/10.1520/JAI103962","url":null,"abstract":"This paper presents the application of the weight function method for the calculation of stress intensity factors for surface semi-elliptical cracks in finite thickness plates subjected to arbitrary two-dimensional stress fields. A new general mathematical form of point load weight function has been formulated by taking advantage of the knowledge of a few specific weight functions for two-dimensional planar cracks available in the literature and certain properties of the weight function in general. The existence of the generalized form of the weight function simplifies the determination of a specific weight function for specific crack configurations. The determination of a specific weight function is reduced to the determination of the parameters of the generalized weight function expression. These unknown parameters can be determined from reference stress intensity factor solutions. This method is used to derive the weight functions for semi-elliptical surface cracks in finite thickness plates. The derived weight functions are then validated against stress intensity factor solutions for several linear and non-linear two-dimensional stress distributions. The derived weight functions are particularly useful for the fatigue crack growth analysis of planar surface cracks subjected to fluctuating nonlinear stress fields resulting from surface treatment (shot peening), stress concentration, or welding (residual stress)","PeriodicalId":15057,"journal":{"name":"Journal of Astm International","volume":"1 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"2012-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82973076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 16
Moisture Sensitive Adhesives and Flooring Adhesive Failures 湿敏粘合剂和地板粘合剂失效
Pub Date : 2012-07-01 DOI: 10.1520/JAI104092
Peter E. Nelson, E. Hopps
Over the last decade, changes in environmental government regulations have necessitated the reformulation of many historically durable adhesives used in the application of flooring materials. The most popular flooring adhesives traditionally used solvents containing volatile organic compounds (VOCs), but government-prescribed regulations that limit or restrict VOCs resulted in dramatic changes to most traditional flooring adhesives. Adhesives with VOC-containing solvents were replaced with water-based or 100 % solids adhesive formulations. While these new formulations may reduce the environmental impact of new flooring installations, new adhesives are less durable and more susceptible to moisture-related deterioration. Within the past ten years more moisture-related flooring failures have occurred as adhesive systems have switched away from the proven VOC-containing technology to a newer, low VOC-compliant technology. If the concrete is not properly sealed or allowed to dry, the moisture inherent to concrete substrates can break down, re-emulsify, and dissolve moisture-sensitive flooring adhesives. Consequentially, applied flooring materials can delaminate, buckle, blister, and crack. This paper will compare the composition of newer moisture-sensitive flooring adhesives with that of their VOC-containing predecessors, and describe the properties of the adhesives that reduce overall durability. Case studies of flooring failures resulting from moisture-related deterioration of adhesives will be presented for various flooring materials including carpet tile, sheet vinyl, and vinyl composition tile flooring. Recommendations for repairing failed flooring and providing durable new flooring installations using moisture-sensitive adhesives will also be included.
在过去的十年中,在环境政府法规的变化已经有必要在地板材料的应用中使用的许多历史上耐用的粘合剂的重新配方。最流行的地板粘合剂传统上使用含有挥发性有机化合物(VOCs)的溶剂,但政府规定的限制或限制VOCs的法规导致大多数传统地板粘合剂发生了巨大变化。使用含voc溶剂的粘合剂被水性或100%固体粘合剂配方所取代。虽然这些新配方可能会减少新地板安装对环境的影响,但新粘合剂的耐用性较差,更容易受到与潮湿有关的变质。在过去的十年里,随着粘合剂系统从成熟的含voc技术转向更新的低voc兼容技术,越来越多与潮湿有关的地板故障发生。如果混凝土密封不当或任其干燥,混凝土基材固有的水分会分解,重新乳化,并溶解对水敏感的地坪粘合剂。因此,应用的地板材料可能分层,扣,起泡和裂纹。本文将比较新型湿敏地板胶粘剂的组成及其含voc的前身,并描述降低整体耐久性的胶粘剂的性能。针对各种地板材料,包括地毯砖、乙烯基板和乙烯基复合地板,将介绍因粘合剂潮湿变质而导致地板失效的案例研究。还将包括修复破损地板和使用湿敏粘合剂提供耐用的新地板装置的建议。
{"title":"Moisture Sensitive Adhesives and Flooring Adhesive Failures","authors":"Peter E. Nelson, E. Hopps","doi":"10.1520/JAI104092","DOIUrl":"https://doi.org/10.1520/JAI104092","url":null,"abstract":"Over the last decade, changes in environmental government regulations have necessitated the reformulation of many historically durable adhesives used in the application of flooring materials. The most popular flooring adhesives traditionally used solvents containing volatile organic compounds (VOCs), but government-prescribed regulations that limit or restrict VOCs resulted in dramatic changes to most traditional flooring adhesives. Adhesives with VOC-containing solvents were replaced with water-based or 100 % solids adhesive formulations. While these new formulations may reduce the environmental impact of new flooring installations, new adhesives are less durable and more susceptible to moisture-related deterioration. Within the past ten years more moisture-related flooring failures have occurred as adhesive systems have switched away from the proven VOC-containing technology to a newer, low VOC-compliant technology. If the concrete is not properly sealed or allowed to dry, the moisture inherent to concrete substrates can break down, re-emulsify, and dissolve moisture-sensitive flooring adhesives. Consequentially, applied flooring materials can delaminate, buckle, blister, and crack. This paper will compare the composition of newer moisture-sensitive flooring adhesives with that of their VOC-containing predecessors, and describe the properties of the adhesives that reduce overall durability. Case studies of flooring failures resulting from moisture-related deterioration of adhesives will be presented for various flooring materials including carpet tile, sheet vinyl, and vinyl composition tile flooring. Recommendations for repairing failed flooring and providing durable new flooring installations using moisture-sensitive adhesives will also be included.","PeriodicalId":15057,"journal":{"name":"Journal of Astm International","volume":"18 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88830227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Crack Closure Behavior on a Variety of Materials under High Stress Ratios and Kmax Test Conditions 不同材料在高应力比和Kmax试验条件下的裂纹闭合行为
Pub Date : 2012-07-01 DOI: 10.1520/JAI103973
Y. Yamada, J. Newman, S. Daniewicz, S. Dean
Fatigue-crack-growth-rate tests on compact specimens have been made on a variety of materials (2024-T3, 2324-T39, 7050-T7451, 4340 steel, and Inconel-718) over a wide range in stress ratios from 0.1 to 0.9 (and 0.95 in some cases) and several Kmax test conditions. Test data has been generated from threshold to near fracture using the compression precracking constant amplitude or compression precracking load reduction test methods in the threshold regime; and constant-amplitude loading at higher rates. A remote back-face strain (BFS) gage was used to monitor crack growth and to measure crack-opening loads. Local strain gages were also placed along and slightly off (about one-half thickness) the anticipated crack path to measure crack-opening loads. Elber’s load-against-reduced-strain method was used to determine crack-opening loads by means of visual inspection (equivalent to a 0 % compliance offset). For a particular material, the BFS and local strain gages produced essentially the same crack-opening loads at low stress ratio (R = 0.1) conditions. But at high stress ratios (R ≥ 0.7) and Kmax test conditions, the local gages produced significantly higher crack-opening loads than the BFS gage in the threshold and near-threshold regimes. Previous research had proposed that high stress ratios (R ≥ 0.7) and Kmax test conditions produce closure-free conditions based on crack-mouth-opening-displacement or BFS gages, and plasticity-induced crack-closure modeling. However, crack closure under high stress ratios (R ≥ 0.7) and Kmax test conditions is attributed to residual-plastic deformations, crack-surface roughness, and/or fretting-debris. From local crack-opening load measurements, the effective stress-intensity-factor range (ΔKeff) appears to be uniquely related to the crack-growth rate in the threshold and near-threshold regimes.
在各种材料(2024-T3、2324-T39、7050-T7451、4340钢和Inconel-718)的应力比范围从0.1到0.9(在某些情况下为0.95)和几个Kmax测试条件下,对致密试样进行了疲劳裂纹扩展速率试验。采用阈值状态下的压缩预裂恒幅或压缩预裂减载试验方法,生成了从阈值到近断裂的试验数据;和更高速率的等幅加载。远程后面应变(BFS)计用于监测裂纹扩展和测量裂纹打开载荷。局部应变片也沿着预期裂纹路径放置,并稍微偏离(约一半厚度),以测量裂纹打开载荷。Elber的荷载-减小应变法用于通过目视检查(相当于0%的柔度偏移)来确定裂纹打开载荷。对于特定材料,在低应力比(R = 0.1)条件下,BFS和局部应变片产生的开裂载荷基本相同。但在高应力比(R≥0.7)和Kmax试验条件下,在阈值和近阈值条件下,局部应变应变产生的开裂载荷明显高于BFS应变应变。先前的研究提出,基于裂纹张开位移或BFS测量以及塑性裂纹闭合模型,高应力比(R≥0.7)和Kmax试验条件会产生无闭合条件。然而,在高应力比(R≥0.7)和Kmax试验条件下,裂纹闭合归因于残余塑性变形、裂纹表面粗糙度和/或微动碎屑。从局部裂纹打开载荷测量中,有效应力强度因子范围(ΔKeff)似乎与阈值和近阈值状态下的裂纹扩展速率唯一相关。
{"title":"Crack Closure Behavior on a Variety of Materials under High Stress Ratios and Kmax Test Conditions","authors":"Y. Yamada, J. Newman, S. Daniewicz, S. Dean","doi":"10.1520/JAI103973","DOIUrl":"https://doi.org/10.1520/JAI103973","url":null,"abstract":"Fatigue-crack-growth-rate tests on compact specimens have been made on a variety of materials (2024-T3, 2324-T39, 7050-T7451, 4340 steel, and Inconel-718) over a wide range in stress ratios from 0.1 to 0.9 (and 0.95 in some cases) and several Kmax test conditions. Test data has been generated from threshold to near fracture using the compression precracking constant amplitude or compression precracking load reduction test methods in the threshold regime; and constant-amplitude loading at higher rates. A remote back-face strain (BFS) gage was used to monitor crack growth and to measure crack-opening loads. Local strain gages were also placed along and slightly off (about one-half thickness) the anticipated crack path to measure crack-opening loads. Elber’s load-against-reduced-strain method was used to determine crack-opening loads by means of visual inspection (equivalent to a 0 % compliance offset). For a particular material, the BFS and local strain gages produced essentially the same crack-opening loads at low stress ratio (R = 0.1) conditions. But at high stress ratios (R ≥ 0.7) and Kmax test conditions, the local gages produced significantly higher crack-opening loads than the BFS gage in the threshold and near-threshold regimes. Previous research had proposed that high stress ratios (R ≥ 0.7) and Kmax test conditions produce closure-free conditions based on crack-mouth-opening-displacement or BFS gages, and plasticity-induced crack-closure modeling. However, crack closure under high stress ratios (R ≥ 0.7) and Kmax test conditions is attributed to residual-plastic deformations, crack-surface roughness, and/or fretting-debris. From local crack-opening load measurements, the effective stress-intensity-factor range (ΔKeff) appears to be uniquely related to the crack-growth rate in the threshold and near-threshold regimes.","PeriodicalId":15057,"journal":{"name":"Journal of Astm International","volume":"45 1","pages":"103973"},"PeriodicalIF":0.0,"publicationDate":"2012-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80274152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
期刊
Journal of Astm International
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1