The Experts below are selected from a list of 5298 Experts worldwide ranked by ideXlab platform
Magd Abdel Wahab - One of the best experts on this subject based on the ideXlab platform.
-
numerical prediction of fretting Fatigue crack trajectory in a railway axle using xfem
International Journal of Fatigue, 2017Co-Authors: Juan Carlos Martinez, Magd Abdel Wahab, Libardo Vanegas V UsecheAbstract:Abstract In this paper, we present for the first time the application of a fretting Fatigue crack propagation predictive technique to a railway axle subjected to bending Fatigue Loading Condition. We also present the first numerical study on predicting Fatigue crack trajectory in an axle and wheel model of a railway axle. The technique is based on combining the eXtended Finite Element Method (XFEM) with two Fatigue crack growth criteria, namely Maximum Tangential Stress (MTS) and minimum shear stress range. In the implementation of XFEM, enrichment functions, shifted formulation and overlay elements are adopted. The element crack closure is taken into account using the punctual restriction criterion. To calculate MTS criterion, the stress intensity factors are extracted using interaction integral method, in which mode I and mode II can be separated. The implementation is validated using a complete contact problem and experimental data from literature. It is found the minimum shear stress range criterion provides crack paths closer to the experimental results than those obtained using MTS criterion. The technique is further applied to a Chinese railway axle and the results are compared to the available experimental data. Good agreement between the numerically predicted and experimentally measured crack trajectory in the railway axle is found.
-
fretting Fatigue stress analysis in heterogeneous material using direct numerical simulations in solid mechanics
Tribology International, 2017Co-Authors: Deepak Kumar, Magd Abdel Wahab, Raja BiswasAbstract:Abstract In this paper, we present the first numerical analysis upon the effect of heterogeneity on the stresses in fretting Fatigue problems. We analyze the stress distribution in heterogeneous material under fretting Fatigue Loading Condition based on Direct Numerical Simulations (DNS) in solid mechanics. The heterogeneity is introduced to the fretting Fatigue specimen using two models based on micro-voids, namely a single hole cell model and a four hole cell model. From this study, it is found that the effect of heterogeneity is more significant in shear stress than in normal stress due to more complex Loading after applying the Fatigue cycle. Moreover, the numerical results indicate that the peak shear stress is shifted from the interface in case of homogeneous material, to the micro-voids in case of heterogeneous material.
-
On fretting Fatigue behaviour of single bolted lap joint
2014Co-Authors: Reza Hojjati Talemi, Magd Abdel Wahab, Tong Yue, Laurent D'alviseAbstract:Fretting Fatigue failure mechanisms occurs between connected parts which are subjected to small oscillatory relative movement and bulk Fatigue Loading Condition at the same time. In this study, fretting Fatigue behaviour of single bolted lap joint connection is investigated by means of finite element modelling approach. To this end, a 3-D finite element model was developed to characterize behaviour of single bolted joint subjected to fretting Fatigue Loading Conditions, which consists of initial crack site estimation, stress and slip distribution at contact interface.
Hyukjae Lee - One of the best experts on this subject based on the ideXlab platform.
-
Characterization of fretting wear behavior of Cu-Al coating on Ti-6Al-4V substrate
Tribology International, 2007Co-Authors: Hyukjae Lee, Shankar Mall, J.h. Sanders, Shashi K. Sharma, Russell S. MagazinerAbstract:Abstract Fretting wear and fretting Fatigue are two commonly observed material damages when two contacting bodies with a clamping load are under the oscillatory motion. In this study, fretting wear damage of Cu–Al coating on titanium alloy, Ti–6Al–4V substrate was investigated using the dissipated energy approach. Fretting tests were conducted with either no Fatigue load or the maximum Fatigue load of 300 MPa and stress ratio of 0.1 on the substrate (specimen). In order to investigate the effect of contact load and contact size, different pad sizes and contact loads were used in the tests. Accumulated dissipated energy versus wear volume data showed a linear relationship regardless of Fatigue Loading Condition on specimen with the smaller pad size. However, two separate linear relationships were observed based on the Fatigue Loading Condition with the larger pad size, such that a relatively more dissipated energy was required for a certain amount of wear with Fatigue load on the specimen. The linear relationship between the accumulated dissipated energy and wear volume for both pad sizes extended from partial to gross slip regimes and was not affected by the applied contact load. Further, fretting tests with and without Fatigue load resulted in different shapes of fretting loops when the larger pad size was used.
-
Evolution of residual stresses in a stress-free titanium alloy subjected to fretting Fatigue☆
Materials Letters, 2006Co-Authors: Hyukjae Lee, Shankar Mall, S. Sathish, M. P. BlodgettAbstract:Abstract This study investigated the complete history of residual stress evolution in a stress-free titanium alloy, Ti–6Al–4 V under fretting Fatigue Loading Condition. Compressive residual stress developed in the contact region due to the local plastic deformation between contacting bodies. The compressive residual stress then increased initially with increasing number of fretting Fatigue cycles reaching to a maximum value, and then it decreased (or relaxed) with further cycling. This relaxation of compressive residual stress was due to the delamination and detachment of flake-like (wear sheet) material in the fretted region.
-
Wear analysis of Cu–Al coating on Ti–6Al–4V substrate under fretting Condition
Tribology Letters, 2005Co-Authors: Hyukjae Lee, S. Mall, J.h. Sanders, Shashi K. SharmaAbstract:Fretting behavior of Cu–Al coating on Ti–6Al–4V substrate was investigated with and without Fatigue load. Soft and rough Cu–Al coating resulted in abrasive wear and a large amount of debris remained at the contact surface, which caused an increase in tangential force during the fretting test under gross slip Condition. Fretting in the partial slip Condition also showed the wear of coating. To characterize wear, dissipated energies during fretting were calculated from fretting loops and wear volumes were obtained from worn surface profiles. Energy approach of wear analysis showed a linear relationship between wear volume and accumulated dissipated energy. This relationship was independent of Fatigue Loading Condition and extended from partial slip to gross slip regimes. As an alternate but simple approach for wear analysis, accumulated relative displacement range was correlated with the wear volume. This also resulted in a linear relationship as in the case of accumulated dissipated energy suggesting that the accumulated relative displacement range can be used as an alternative parameter for dissipated energy to characterize the wear. When the maximum wear depth was equal to the thickness of Cu–Al coating, harder Ti–6Al–4V substrate inhibited further increase in wear depth. Only when a considerable energy was supplied through a large value of the applied displacement, wear in the substrate material could occur beyond the thickness of coating.
-
Characterization of Wear of a Soft Coating Deposited on Titanium Alloy During Fretting
World Tribology Congress III Volume 1, 2005Co-Authors: Hyukjae Lee, Shankar Mall, J.h. Sanders, Shashi K. SharmaAbstract:Fretting behavior of Cu-Al coating on Ti-6Al-4V substrate was investigated with and without Fatigue load. Soft and rough Cu-Al coating resulted in abrasive wear and a large amount of debris remained at the contact surface which caused an increase in tangential force during the fretting test under gross slip Condition. Fretting in the partial slip Condition also showed the wear of coating. To characterize wear, dissipated energies during fretting were calculated from fretting loops and wear volumes were obtained from worn surface profiles. Energy approach of wear analysis showed a linear relationship between wear volume and accumulated dissipated energy. This relationship was independent of Fatigue Loading Condition and extended from partial slip to gross slip regimes.Copyright © 2005 by ASME
-
Wear analysis of Cu–Al coating on Ti–6Al–4V substrate under fretting Condition
Tribology Letters, 2005Co-Authors: Hyukjae Lee, Shankar Mall, J.h. Sanders, Shashi K. SharmaAbstract:Fretting behavior of Cu–Al coating on Ti–6Al–4V substrate was investigated with and without Fatigue load. Soft and rough Cu–Al coating resulted in abrasive wear and a large amount of debris remained at the contact surface, which caused an increase in tangential force during the fretting test under gross slip Condition. Fretting in the partial slip Condition also showed the wear of coating. To characterize wear, dissipated energies during fretting were calculated from fretting loops and wear volumes were obtained from worn surface profiles. Energy approach of wear analysis showed a linear relationship between wear volume and accumulated dissipated energy. This relationship was independent of Fatigue Loading Condition and extended from partial slip to gross slip regimes. As an alternate but simple approach for wear analysis, accumulated relative displacement range was correlated with the wear volume. This also resulted in a linear relationship as in the case of accumulated dissipated energy suggesting that the accumulated relative displacement range can be used as an alternative parameter for dissipated energy to characterize the wear. When the maximum wear depth was equal to the thickness of Cu–Al coating, harder Ti–6Al–4V substrate inhibited further increase in wear depth. Only when a considerable energy was supplied through a large value of the applied displacement, wear in the substrate material could occur beyond the thickness of coating.
Shashi K. Sharma - One of the best experts on this subject based on the ideXlab platform.
-
Characterization of fretting wear behavior of Cu-Al coating on Ti-6Al-4V substrate
Tribology International, 2007Co-Authors: Hyukjae Lee, Shankar Mall, J.h. Sanders, Shashi K. Sharma, Russell S. MagazinerAbstract:Abstract Fretting wear and fretting Fatigue are two commonly observed material damages when two contacting bodies with a clamping load are under the oscillatory motion. In this study, fretting wear damage of Cu–Al coating on titanium alloy, Ti–6Al–4V substrate was investigated using the dissipated energy approach. Fretting tests were conducted with either no Fatigue load or the maximum Fatigue load of 300 MPa and stress ratio of 0.1 on the substrate (specimen). In order to investigate the effect of contact load and contact size, different pad sizes and contact loads were used in the tests. Accumulated dissipated energy versus wear volume data showed a linear relationship regardless of Fatigue Loading Condition on specimen with the smaller pad size. However, two separate linear relationships were observed based on the Fatigue Loading Condition with the larger pad size, such that a relatively more dissipated energy was required for a certain amount of wear with Fatigue load on the specimen. The linear relationship between the accumulated dissipated energy and wear volume for both pad sizes extended from partial to gross slip regimes and was not affected by the applied contact load. Further, fretting tests with and without Fatigue load resulted in different shapes of fretting loops when the larger pad size was used.
-
Wear analysis of Cu–Al coating on Ti–6Al–4V substrate under fretting Condition
Tribology Letters, 2005Co-Authors: Hyukjae Lee, S. Mall, J.h. Sanders, Shashi K. SharmaAbstract:Fretting behavior of Cu–Al coating on Ti–6Al–4V substrate was investigated with and without Fatigue load. Soft and rough Cu–Al coating resulted in abrasive wear and a large amount of debris remained at the contact surface, which caused an increase in tangential force during the fretting test under gross slip Condition. Fretting in the partial slip Condition also showed the wear of coating. To characterize wear, dissipated energies during fretting were calculated from fretting loops and wear volumes were obtained from worn surface profiles. Energy approach of wear analysis showed a linear relationship between wear volume and accumulated dissipated energy. This relationship was independent of Fatigue Loading Condition and extended from partial slip to gross slip regimes. As an alternate but simple approach for wear analysis, accumulated relative displacement range was correlated with the wear volume. This also resulted in a linear relationship as in the case of accumulated dissipated energy suggesting that the accumulated relative displacement range can be used as an alternative parameter for dissipated energy to characterize the wear. When the maximum wear depth was equal to the thickness of Cu–Al coating, harder Ti–6Al–4V substrate inhibited further increase in wear depth. Only when a considerable energy was supplied through a large value of the applied displacement, wear in the substrate material could occur beyond the thickness of coating.
-
Characterization of Wear of a Soft Coating Deposited on Titanium Alloy During Fretting
World Tribology Congress III Volume 1, 2005Co-Authors: Hyukjae Lee, Shankar Mall, J.h. Sanders, Shashi K. SharmaAbstract:Fretting behavior of Cu-Al coating on Ti-6Al-4V substrate was investigated with and without Fatigue load. Soft and rough Cu-Al coating resulted in abrasive wear and a large amount of debris remained at the contact surface which caused an increase in tangential force during the fretting test under gross slip Condition. Fretting in the partial slip Condition also showed the wear of coating. To characterize wear, dissipated energies during fretting were calculated from fretting loops and wear volumes were obtained from worn surface profiles. Energy approach of wear analysis showed a linear relationship between wear volume and accumulated dissipated energy. This relationship was independent of Fatigue Loading Condition and extended from partial slip to gross slip regimes.Copyright © 2005 by ASME
-
Wear analysis of Cu–Al coating on Ti–6Al–4V substrate under fretting Condition
Tribology Letters, 2005Co-Authors: Hyukjae Lee, Shankar Mall, J.h. Sanders, Shashi K. SharmaAbstract:Fretting behavior of Cu–Al coating on Ti–6Al–4V substrate was investigated with and without Fatigue load. Soft and rough Cu–Al coating resulted in abrasive wear and a large amount of debris remained at the contact surface, which caused an increase in tangential force during the fretting test under gross slip Condition. Fretting in the partial slip Condition also showed the wear of coating. To characterize wear, dissipated energies during fretting were calculated from fretting loops and wear volumes were obtained from worn surface profiles. Energy approach of wear analysis showed a linear relationship between wear volume and accumulated dissipated energy. This relationship was independent of Fatigue Loading Condition and extended from partial slip to gross slip regimes. As an alternate but simple approach for wear analysis, accumulated relative displacement range was correlated with the wear volume. This also resulted in a linear relationship as in the case of accumulated dissipated energy suggesting that the accumulated relative displacement range can be used as an alternative parameter for dissipated energy to characterize the wear. When the maximum wear depth was equal to the thickness of Cu–Al coating, harder Ti–6Al–4V substrate inhibited further increase in wear depth. Only when a considerable energy was supplied through a large value of the applied displacement, wear in the substrate material could occur beyond the thickness of coating.
Shankar Mall - One of the best experts on this subject based on the ideXlab platform.
-
Investigation into Wear Behavior of Cu-Al Coating on Titanium alloy under Fretting Fatigue
48th AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference, 2007Co-Authors: S.-m. Lee, Shankar MallAbstract:Fretting tests were conducted with either no Fatigue load or with Fatigue load to investigate the effect of contact load and contact size. Accumulated dissipated energy versus wear volume data showed a linear relationship regardless of Fatigue Loading Condition on specimen with the smaller pad size. However, two separate linear relationships were observed based on the Fatigue Loading Condition with the larger pad size, such that a relatively more dissipated energy was required for a certain amount of wear with Fatigue load on the specimen. The linear relationship between the accumulated dissipated energy and wear volume for both pad sizes extended from partial to gross slip regimes and was not affected by the applied contact load.
-
Characterization of fretting wear behavior of Cu-Al coating on Ti-6Al-4V substrate
Tribology International, 2007Co-Authors: Hyukjae Lee, Shankar Mall, J.h. Sanders, Shashi K. Sharma, Russell S. MagazinerAbstract:Abstract Fretting wear and fretting Fatigue are two commonly observed material damages when two contacting bodies with a clamping load are under the oscillatory motion. In this study, fretting wear damage of Cu–Al coating on titanium alloy, Ti–6Al–4V substrate was investigated using the dissipated energy approach. Fretting tests were conducted with either no Fatigue load or the maximum Fatigue load of 300 MPa and stress ratio of 0.1 on the substrate (specimen). In order to investigate the effect of contact load and contact size, different pad sizes and contact loads were used in the tests. Accumulated dissipated energy versus wear volume data showed a linear relationship regardless of Fatigue Loading Condition on specimen with the smaller pad size. However, two separate linear relationships were observed based on the Fatigue Loading Condition with the larger pad size, such that a relatively more dissipated energy was required for a certain amount of wear with Fatigue load on the specimen. The linear relationship between the accumulated dissipated energy and wear volume for both pad sizes extended from partial to gross slip regimes and was not affected by the applied contact load. Further, fretting tests with and without Fatigue load resulted in different shapes of fretting loops when the larger pad size was used.
-
Evolution of residual stresses in a stress-free titanium alloy subjected to fretting Fatigue☆
Materials Letters, 2006Co-Authors: Hyukjae Lee, Shankar Mall, S. Sathish, M. P. BlodgettAbstract:Abstract This study investigated the complete history of residual stress evolution in a stress-free titanium alloy, Ti–6Al–4 V under fretting Fatigue Loading Condition. Compressive residual stress developed in the contact region due to the local plastic deformation between contacting bodies. The compressive residual stress then increased initially with increasing number of fretting Fatigue cycles reaching to a maximum value, and then it decreased (or relaxed) with further cycling. This relaxation of compressive residual stress was due to the delamination and detachment of flake-like (wear sheet) material in the fretted region.
-
Fatigue Response of Joint between Titanium and Titanium Matrix Composite
47th AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference<BR> 14th AIAA ASME AHS Adaptive Structures Conference<BR&, 2006Co-Authors: Shankar Mall, Scott CunninghamAbstract:An integrally fabricated double scarf joint between a monolithic titanium alloy and the silicon carbide fiber reinforced titanium matrix composite was characterized under the Fatigue Loading Condition. The mechanical response of the functionally graded material system was in-between those of the alloy and the composite under all Loading Conditions. There was a small improvement in Fatigue life of the functionally graded material relative to that of the monolithic alloy.
-
Characterization of Wear of a Soft Coating Deposited on Titanium Alloy During Fretting
World Tribology Congress III Volume 1, 2005Co-Authors: Hyukjae Lee, Shankar Mall, J.h. Sanders, Shashi K. SharmaAbstract:Fretting behavior of Cu-Al coating on Ti-6Al-4V substrate was investigated with and without Fatigue load. Soft and rough Cu-Al coating resulted in abrasive wear and a large amount of debris remained at the contact surface which caused an increase in tangential force during the fretting test under gross slip Condition. Fretting in the partial slip Condition also showed the wear of coating. To characterize wear, dissipated energies during fretting were calculated from fretting loops and wear volumes were obtained from worn surface profiles. Energy approach of wear analysis showed a linear relationship between wear volume and accumulated dissipated energy. This relationship was independent of Fatigue Loading Condition and extended from partial slip to gross slip regimes.Copyright © 2005 by ASME
Young Hwan Choi - One of the best experts on this subject based on the ideXlab platform.
-
Socket weld integrity in nuclear piping under Fatigue Loading Condition
Nuclear Engineering and Design, 2007Co-Authors: Young Hwan Choi, Sun Yeong ChoiAbstract:Abstract The purpose of this paper is to evaluate the integrity of socket weld in nuclear piping under the Fatigue Loading. The integrity of socket weld is regarded as a safety concern in nuclear power plants because many failures have been world-widely reported in the socket weld. Recently, socket weld failures in the chemical and volume control system (CVCS) and the primary sampling system (PSS) were reported in Korean nuclear power plants. The root causes of the socket weld failures were known as the Fatigue due to the pressure and/or temperature Loading transients and the vibration during the plant operation. The ASME boiler and pressure vessel (B & PV) Code Sec. III requires 1/16 in. gap between the pipe and fitting in the socket weld with the weld leg size of 1.09 × t1, where t1 is the pipe wall thickness. Many failure cases, however, showed that the gap requirement was not satisfied. In addition, industry has demanded the reduction of weld leg size from 1.09 × t1 to 0.75 × t1. In this paper, the socket weld integrity under the Fatigue Loading was evaluated using three-dimensional finite element analysis considering the requirements in the ASME Code. Three types of Loading Conditions such as the deflection due to vibration, the pressure transient ranging from P = 0 to 15.51 MPa, and the thermal transient ranging from T = 25 to 288 °C were considered. The results are as follows; (1) the socket weld is susceptible to the vibration where the vibration levels exceed the requirement in the ASME operation and maintenance (OM) code. (2) The effect of pressure or temperature transient load on socket weld in CVCS and PSS is not significant owing to the low frequency of transient during plant operation. (3) ‘No gap’ is very risky to the socket weld integrity for the systems having the vibration Condition to exceed the requirement specified in the ASME OM Code and/or the transient Loading Condition from P = 0 and T = 25 °C to P = 15.51 MPa and T = 288 °C. (4) The reduction of the weld leg size from 1.09 × t1 to 0.75 × t1 may induce detrimental effect on the socket weld integrity.
-
Socket Weld Integrity in Nuclear Piping under Fatigue Loading Condition
Solid State Phenomena, 2007Co-Authors: Young Hwan Choi, Sun Yeong Choi, Nam Soo HuhAbstract:The purpose of this paper is to evaluate the integrity of socket weld in nuclear piping under the Fatigue Loading. The integrity of socket weld is regarded as a safety concern in nuclear power plants because many failures have been world-widely reported in the socket weld. Recently, socket weld failures in the chemical and volume control system (CVCS) and the primary sampling system (PSS) were reported in Korean nuclear power plants. The root causes of socket weld failures were known as the Fatigue due to the pressure and/or temperature Loading transients and the vibration during the plant operation. The ASME Boiler and Pressure Vessel (B & PV) Code Sec. III requires 1/16 inch gap between the pipe and fitting in the socket weld with the weld leg size of 1.09*t 1 , where t 1 is the pipe wall thickness. Many failure cases, however, showed that the gap requirement was not satisfied. In this paper, the socket weld integrity under the Fatigue Loading was evaluated using three-dimensional finite element analysis considering the requirements in the ASME Code. Three types of Loading Conditions such as the deflection due to vibration, the pressure transient ranging from P=0 to 15.51 MPa, and the thermal transient ranging from T=25 °C to 288 °C were considered. The results are as follows; (1) The socket weld is susceptible to the vibration where the vibration levels exceed the requirement in the ASME Operation and Maintenance (OM) Code [9]. (2) The effect of pressure or temperature transient load on socket weld in CVCS and PSS is not significant owing to the low frequency of transient during plant operation. (3) 'No gap' is very risky to the socket weld integrity for the systems having the vibration Condition to exceed the requirement specified in the ASME OM Code and/or the transient Loading Condition from P=0 and T=25 °C to P=15.51 MPa and T=288 °C.
-
Surface Crack Behavior in Socket Weld of Nuclear Piping under Fatigue Loading Condition
Key Engineering Materials, 2005Co-Authors: Young Hwan Choi, Sun Yeong Choi, Jin-su KimAbstract:The ASME B & PV Code Sec. allows the socket weld for the nuclear piping in spite of the weakness on the weld integrity. Recently, the integrity of the socket weld is regarded as a safety concern in nuclear power plants because many failures and leaks have been reported in the socket weld. OPDE (OECD Piping Failure Data Exchange) database lists 108 socket weld failures among 2,399 nuclear piping failure cases during 1970 to 2001. Eleven failures in the socket weld were also reported in Korean NPPs. Many failure cases showed that the root cause of the failure is the Fatigue and the gap requirement for the socket weld given in ASME Code was not satisfied. The purpose of this paper is to evaluate the Fatigue crack behavior of a surface crack in the socket weld under Fatigue Loading Condition considering the gap effect. Three-dimensional finite element analysis was performed to estimate the Fatigue crack behavior of the surface crack. Three types of Loading Conditions such as the deflection due to vibration, the pressure transient ranging from P=0 to 15.51MPa, and the thermal transient ranging from T=25oC to 288oC were considered. The results are as follows; 1) The socket weld is susceptible to the vibration where the vibration levels exceed the requirement in the ASME Operation and Maintenance (OM) Code. 2) The effect of pressure or Temperature transient load on the socket weld integrity is not significant. 3) No-gap Condition gives very high possibility of the crack initiation at the socket weld under vibration Loading Condition. 4) For the specific systems having the vibration Condition to exceed the requirement in the ASME Code OM and/or the transient Loading Condition from P=0 and T=25oC to P=15.51MPa and T=288oC, radiographic examination to examine the gap during the construction stage is recommended.
