The notched round bar (NRB) geometry was assessed for use with ASTM E 1921-97 Standard for Test Method for the Determination of Reference Temperature, T 0 , for Ferritic Steels in the Transition Range. Instead of precracking the NRB specimens, apparent fracture toughness using three different notch root radii was extrapolated to a zero radius to infer sharp crack fracture toughness. The reference temperature using A302B NRB specimens was determined to be -89°C, while A3028 C(T) specimens yield To of -87.3°C. In applying ASTM E 1921 to the NRB geometry, a simple scheme to remove notch root radius bias from apparent fracture toughness was developed. In addition, a size correction for converting NRB results to comparable IT-C(T) results was investigated.
缺口圆棒(NRB)的几何形状根据ASTM E 1921-97在过渡范围内测定铁素体钢参考温度的试验方法t0标准进行了评估。采用三种不同的缺口根半径，将NRB试样的表观断裂韧性外推至零半径，从而推断出锐裂纹断裂韧性，而不是预裂。A302B NRB样品的参考温度为-89°C，而A3028 C(T)样品的屈服温度为-87.3°C。在将ASTM E 1921应用于NRB几何形状时，开发了一种从表观断裂韧性中去除缺口根半径偏差的简单方案。此外，研究了将NRB结果转换为可比较的IT-C(T)结果的大小校正。
{"title":"Transition fracture toughness testing with notched round bars (NRB)","authors":"Christopher D. Wilson, J. Landes","doi":"10.1520/STP14806S","DOIUrl":"https://doi.org/10.1520/STP14806S","url":null,"abstract":"The notched round bar (NRB) geometry was assessed for use with ASTM E 1921-97 Standard for Test Method for the Determination of Reference Temperature, T 0 , for Ferritic Steels in the Transition Range. Instead of precracking the NRB specimens, apparent fracture toughness using three different notch root radii was extrapolated to a zero radius to infer sharp crack fracture toughness. The reference temperature using A302B NRB specimens was determined to be -89°C, while A3028 C(T) specimens yield To of -87.3°C. In applying ASTM E 1921 to the NRB geometry, a simple scheme to remove notch root radius bias from apparent fracture toughness was developed. In addition, a size correction for converting NRB results to comparable IT-C(T) results was investigated.","PeriodicalId":8583,"journal":{"name":"ASTM special technical publications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89588065","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}
The elastic and elastic-plastic fracture mechanics parameters of surface cracks in compressor disks of aircraft engines are evaluated using both the finite element method and the weight function method. First, a three-dimensional finite element model of a low-pressure compressor disk containing a surface crack at the snap radius is developed. The stress intensity factor distributions along the surface crack front with various crack shapes and sizes in the disk under a typical engine operation condition are calculated. Then, the effect of biaxial stresses on the stress intensity factor of a crack emanating from a tie bolt hole in a representative compressor disk is investigated using the weight function approach. Emphasis is given to determining the effect of the bolt hole plastic zone on the fracture parameters when the compressor disk is highly loaded. Finally, a new theoretical model for the estimation of the fracture parameters of a through-thickness crack in the web region is proposed using a definition of local biaxial stress ratio. The studies show that the developed model can provide better estimation of the plastic zone size and the crack-tip opening displacement than those existing models.
{"title":"Fracture Parameters of Surface Cracks in Compressor Disks","authors":"W. Zhuang, B. J. Wicks","doi":"10.1520/STP14811S","DOIUrl":"https://doi.org/10.1520/STP14811S","url":null,"abstract":"The elastic and elastic-plastic fracture mechanics parameters of surface cracks in compressor disks of aircraft engines are evaluated using both the finite element method and the weight function method. First, a three-dimensional finite element model of a low-pressure compressor disk containing a surface crack at the snap radius is developed. The stress intensity factor distributions along the surface crack front with various crack shapes and sizes in the disk under a typical engine operation condition are calculated. Then, the effect of biaxial stresses on the stress intensity factor of a crack emanating from a tie bolt hole in a representative compressor disk is investigated using the weight function approach. Emphasis is given to determining the effect of the bolt hole plastic zone on the fracture parameters when the compressor disk is highly loaded. Finally, a new theoretical model for the estimation of the fracture parameters of a through-thickness crack in the web region is proposed using a definition of local biaxial stress ratio. The studies show that the developed model can provide better estimation of the plastic zone size and the crack-tip opening displacement than those existing models.","PeriodicalId":8583,"journal":{"name":"ASTM special technical publications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89826463","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}
Los Alamos National Laboratory (LANL) has developed an ecological screening evaluation process that emphasizes the development and testing of an ecological exposure and transport pathway site conceptual model. LANL developed this screening approach in partnership with personnel from the State of New Mexico regulatory authority (the New Mexico Environment Department or NMED). A key part of the screening evaluation process is the completion of an innovative ecological scoping checklist. This checklist helps to (1) determine if complete pathways to ecological receptors exist; (2) determine how the impacted media should be aggregated spatially for screening, establishing the functional/operational boundaries of the assessment; and (3) gather information to develop the site conceptual model (SCM). The SCM includes contaminant sources, dominant transport pathways and exposure routes, and potential receptors. The scoping checklist consists of a series of questions and placeholders for field notes, which are intended to guide the risk assessor in developing the SCM, and provide the decision-makers with consistent information on receptors, potential transport pathways and potential exposure pathways. This paper summarizes the LANL/NMED scoping checklist and gives examples of its application at the LANL Environmental Restoration (ER) sites.
洛斯阿拉莫斯国家实验室(Los Alamos National Laboratory, LANL)开发了一个生态筛选评估过程，强调生态暴露和运输途径站点概念模型的开发和测试。LANL与新墨西哥州监管机构(新墨西哥州环境部或NMED)的人员合作开发了这种筛选方法。筛选评估过程的一个关键部分是完成创新的生态范围检查清单。这个清单有助于(1)确定是否存在完整的生态受体通路;(2)确定受影响的介质应如何在空间上聚集以进行筛选，建立评估的功能/操作边界;(3)收集信息，开发站点概念模型(SCM)。SCM包括污染源、主要运输途径和暴露途径以及潜在受体。范围界定清单由一系列问题和实地记录占位符组成，旨在指导风险评估人员制定SCM，并向决策者提供关于受体、潜在运输途径和潜在暴露途径的一致信息。本文总结了LANL/NMED的范围清单，并给出了其在LANL环境恢复(ER)站点的应用实例。
{"title":"Using Ecological Site Scoping to Evaluate Contaminant Transport Pathways","authors":"R. Ryti, E. Kelly","doi":"10.1520/STP14419S","DOIUrl":"https://doi.org/10.1520/STP14419S","url":null,"abstract":"Los Alamos National Laboratory (LANL) has developed an ecological screening evaluation process that emphasizes the development and testing of an ecological exposure and transport pathway site conceptual model. LANL developed this screening approach in partnership with personnel from the State of New Mexico regulatory authority (the New Mexico Environment Department or NMED). A key part of the screening evaluation process is the completion of an innovative ecological scoping checklist. This checklist helps to (1) determine if complete pathways to ecological receptors exist; (2) determine how the impacted media should be aggregated spatially for screening, establishing the functional/operational boundaries of the assessment; and (3) gather information to develop the site conceptual model (SCM). The SCM includes contaminant sources, dominant transport pathways and exposure routes, and potential receptors. The scoping checklist consists of a series of questions and placeholders for field notes, which are intended to guide the risk assessor in developing the SCM, and provide the decision-makers with consistent information on receptors, potential transport pathways and potential exposure pathways. This paper summarizes the LANL/NMED scoping checklist and gives examples of its application at the LANL Environmental Restoration (ER) sites.","PeriodicalId":8583,"journal":{"name":"ASTM special technical publications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73018589","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}
Chih‐Ping Lin, S. I. Siddiqui, W. Feng, V. Drnevich, R. Deschamps
{"title":"Quality Control of Earth Fills Using Time Domain Reflectometry (TDR)","authors":"Chih‐Ping Lin, S. I. Siddiqui, W. Feng, V. Drnevich, R. Deschamps","doi":"10.1520/STP15291S","DOIUrl":"https://doi.org/10.1520/STP15291S","url":null,"abstract":"","PeriodicalId":8583,"journal":{"name":"ASTM special technical publications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73373367","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}
It is shown that pre-crack and early stage fatigue damage can be characterized by a new sensor technology, the Meandering Winding Magnetometer (MWM). This new technology consists of a conformable sensor, the MWM, and associated measurement grids that are model based. Measurements on type 304 stainless steel indicated that damage is readily detectable at 20% of life (N/N F = 0.2) and causes a 1.5% conductivity loss. Near failure the conductivity loss in the crack-free region was approximately 4%. In 2024 aluminum the onset of detectable fatigue damage was observed at approximately 50% of total life. For the probe geometry employed, the conductivity loss in the microcrack region iust prior to failure was 7%: in the macrocrack region it reached 13%.
结果表明，弯曲绕组磁强计(MWM)是一种新型传感器技术，可用于表征材料的预裂纹和早期疲劳损伤。这项新技术由一个兼容的传感器、MWM和相关的基于模型的测量网格组成。对304型不锈钢的测量表明，损坏在寿命的20% (N/N F = 0.2)时很容易检测到，并导致1.5%的导电性损失。接近失效时，无裂纹区域的电导率损失约为4%。在2024铝合金中，可检测的疲劳损伤发生在总寿命的50%左右。对于所采用的探针几何形状，失效前微裂纹区域的电导率损失为7%，而在大裂纹区域，电导率损失达到13%。
{"title":"Early stage fatigue damage characterization in aluminum alloys and stainless steels with Meandering Winding Magnetometer technology","authors":"V. Weiss, N. Goldfine, M. Natishan","doi":"10.1520/STP13418S","DOIUrl":"https://doi.org/10.1520/STP13418S","url":null,"abstract":"It is shown that pre-crack and early stage fatigue damage can be characterized by a new sensor technology, the Meandering Winding Magnetometer (MWM). This new technology consists of a conformable sensor, the MWM, and associated measurement grids that are model based. Measurements on type 304 stainless steel indicated that damage is readily detectable at 20% of life (N/N F = 0.2) and causes a 1.5% conductivity loss. Near failure the conductivity loss in the crack-free region was approximately 4%. In 2024 aluminum the onset of detectable fatigue damage was observed at approximately 50% of total life. For the probe geometry employed, the conductivity loss in the microcrack region iust prior to failure was 7%: in the macrocrack region it reached 13%.","PeriodicalId":8583,"journal":{"name":"ASTM special technical publications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78462502","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}
Toshiro Kobayashi, Naoya Inoue, S. Morita, H. Toda
{"title":"On the accuracy of measurement and calibration of load signal in the instrumented Charpy impact test","authors":"Toshiro Kobayashi, Naoya Inoue, S. Morita, H. Toda","doi":"10.1520/STP14395S","DOIUrl":"https://doi.org/10.1520/STP14395S","url":null,"abstract":"","PeriodicalId":8583,"journal":{"name":"ASTM special technical publications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75676922","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 tests are performed on tubular specimens of stainless steel 304 under variable amplitude, irregular axial-torsional loading. Three parameters are chosen for correlating fatigue life: the Smith-Watson-Topper (SWT) parameter for normal fracture, Fatemi-Socie (FS), and Kandil-Brown-Miller parameters (KBM) for shear fracture. A life computation procedure is employed in which rainflow cycle counting on normal (SWT) or shear (FS, KBM) strain history and the Miner-Palmgren rule are used. It is found that, while the life calculation procedure appears to be viable and each parameter yields acceptable results for most loading conditions, there are cases for which correlation is poor. The SWT parameter performed well except for torsion-dominated cycles, where it overpredicted lives. The FS and KBM parameters did better than the SWT parameter in torsion, but showed poor performance in some other loading conditions.
{"title":"Biaxial Fatigue of stainless steel 304 under irregular loading","authors":"K. S. Kim, Bl Lee, J.C. Park","doi":"10.1520/STP14795S","DOIUrl":"https://doi.org/10.1520/STP14795S","url":null,"abstract":"Fatigue tests are performed on tubular specimens of stainless steel 304 under variable amplitude, irregular axial-torsional loading. Three parameters are chosen for correlating fatigue life: the Smith-Watson-Topper (SWT) parameter for normal fracture, Fatemi-Socie (FS), and Kandil-Brown-Miller parameters (KBM) for shear fracture. A life computation procedure is employed in which rainflow cycle counting on normal (SWT) or shear (FS, KBM) strain history and the Miner-Palmgren rule are used. It is found that, while the life calculation procedure appears to be viable and each parameter yields acceptable results for most loading conditions, there are cases for which correlation is poor. The SWT parameter performed well except for torsion-dominated cycles, where it overpredicted lives. The FS and KBM parameters did better than the SWT parameter in torsion, but showed poor performance in some other loading conditions.","PeriodicalId":8583,"journal":{"name":"ASTM special technical publications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77638370","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}
The consideration of fracture behavior should be a matter of vital concern in current design efforts. Many materials exhibit grossly different behavior when discontinuities are present in the structure. These may be inherent in the material or may stem from poor manufacturing, handling, and/or design practices. Inclusion of fracture behavior in the design models is the subject of fracture mechanics. Ultimately, a knowledge of fatigue and fracture becomes very important in avoiding disaster. This paper is written with two primary purposes: to characterize the physical nature of fracture, and to dramatize the need to characterize the central flat fracture differently from the surface, shear fracture. To this end, the contents of the paper are organized as follows: (1) validity limits of fracture mechanics: this information was originally developed for the purpose of extracting similar fracture data and will be used here to help characterize bulk constraint effects and to establish the existence of the surface effect; (2) analysis of crack face displacements of planar specimens subjected to loads: this includes actual crack-, separation-, and stretch-profiles; and (3) consideration of three-dimensional fracture in light of the existence of two distinct fracture zones that exhibit different failure mechanisms; for this purpose, G and J as a functitin of depth below surface are discussed, as well as several constraint factors as a function of depth.
{"title":"Fracture mechanics validity limits and physical evidence of constraint in fracture","authors":"D. Lambert, H. Ernst","doi":"10.1520/STP13399S","DOIUrl":"https://doi.org/10.1520/STP13399S","url":null,"abstract":"The consideration of fracture behavior should be a matter of vital concern in current design efforts. Many materials exhibit grossly different behavior when discontinuities are present in the structure. These may be inherent in the material or may stem from poor manufacturing, handling, and/or design practices. Inclusion of fracture behavior in the design models is the subject of fracture mechanics. Ultimately, a knowledge of fatigue and fracture becomes very important in avoiding disaster. This paper is written with two primary purposes: to characterize the physical nature of fracture, and to dramatize the need to characterize the central flat fracture differently from the surface, shear fracture. To this end, the contents of the paper are organized as follows: (1) validity limits of fracture mechanics: this information was originally developed for the purpose of extracting similar fracture data and will be used here to help characterize bulk constraint effects and to establish the existence of the surface effect; (2) analysis of crack face displacements of planar specimens subjected to loads: this includes actual crack-, separation-, and stretch-profiles; and (3) consideration of three-dimensional fracture in light of the existence of two distinct fracture zones that exhibit different failure mechanisms; for this purpose, G and J as a functitin of depth below surface are discussed, as well as several constraint factors as a function of depth.","PeriodicalId":8583,"journal":{"name":"ASTM special technical publications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86922425","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":"Compaction and Performance of Loess Embankments","authors":"Liming Zhang, Jia-Yang Du, T. Hu","doi":"10.1520/STP15283S","DOIUrl":"https://doi.org/10.1520/STP15283S","url":null,"abstract":"","PeriodicalId":8583,"journal":{"name":"ASTM special technical publications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90704157","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}
Isothermal fatigue tests were performed on unnotched quasiisotropic SCS-6/Timetal 21S (Ti-15Mo-2.6Nb-3Al-0.2Si) composites at room temperature, 400°C and 500°C with various hold times (0, 1 and 10 seconds). The specimen tested at 500°C showed significant oxidation, especially along the grain boundaries. In addition, there were changes in various physical properties of the composites at elevated temperatures: oxidation, phase transformation, viscoplastic flow of matrix, and interface reaction. The measurement of oxide thickness of both with and without load indicated that the oxidation of the matrix material was more severe with applied load than without load for the same amount of exposure time. Simple spectrum loading tests were conducted to examine the effect of test temperature on the formation of oxidation and its influence on the damage accumulation in the composites. Different numbers of applied cycles per block were used: n 1 and n 2 = 10, 100, and 1000 cycles. The change in temperature along with stress acted as thermal cycle that further introduced damages into the composites and reduced their life. As the number of applied cycles increased, the failure life of the composites was increased. The small number of cycles per block showed a shorter life due to more frequent changes in temperature level.
{"title":"The Role of Oxidation on the Thermo-mechanical Fatigue of Timetal 21S Matrix Composites","authors":"O. Jin, W. Johnson","doi":"10.1520/STP15262S","DOIUrl":"https://doi.org/10.1520/STP15262S","url":null,"abstract":"Isothermal fatigue tests were performed on unnotched quasiisotropic SCS-6/Timetal 21S (Ti-15Mo-2.6Nb-3Al-0.2Si) composites at room temperature, 400°C and 500°C with various hold times (0, 1 and 10 seconds). The specimen tested at 500°C showed significant oxidation, especially along the grain boundaries. In addition, there were changes in various physical properties of the composites at elevated temperatures: oxidation, phase transformation, viscoplastic flow of matrix, and interface reaction. The measurement of oxide thickness of both with and without load indicated that the oxidation of the matrix material was more severe with applied load than without load for the same amount of exposure time. Simple spectrum loading tests were conducted to examine the effect of test temperature on the formation of oxidation and its influence on the damage accumulation in the composites. Different numbers of applied cycles per block were used: n 1 and n 2 = 10, 100, and 1000 cycles. The change in temperature along with stress acted as thermal cycle that further introduced damages into the composites and reduced their life. As the number of applied cycles increased, the failure life of the composites was increased. The small number of cycles per block showed a shorter life due to more frequent changes in temperature level.","PeriodicalId":8583,"journal":{"name":"ASTM special technical publications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89527680","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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