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.
{"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":null,"pages":null},"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}
{"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":null,"pages":null},"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}
{"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":null,"pages":null},"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}
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.
{"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":null,"pages":null},"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}
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.
{"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":null,"pages":null},"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}
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.
{"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":null,"pages":null},"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}
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.
{"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":null,"pages":null},"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}
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)
{"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":null,"pages":null},"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}
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.
{"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":null,"pages":null},"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}
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.
{"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":null,"pages":null},"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}
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