Sharif Ullah Khan | Delft University of Technology (original) (raw)
Papers by Sharif Ullah Khan
Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
This paper presents the experimental and analytical research on the applicability of Linear Damag... more This paper presents the experimental and analytical research on the applicability of Linear Damage Accumulation Rule for fatigue crack growth in Fibre reinforced Metal Laminates under variable amplitude loading. A recently developed constant amplitude analytical prediction model has been extended to predict fatigue crack growth under variable amplitude loading using a linear damage accumulation rule. The modified model has been compared with crack growth tests on Fibre reinforced Metal Laminates centre-cracked tension specimen. In the end it is discussed to what extent or under what conditions the linear damage accumulation predictions are sufficiently accurate for Fibre reinforced Metal Laminates structures.
Journal of Aircraft, 2009
FATIGUE is no doubt the main cause of failure in most load bearing components. The type of loadin... more FATIGUE is no doubt the main cause of failure in most load bearing components. The type of loading in nature is mainly based on variable amplitude which largely affects the severity and mechanisms of failure. In the case of metallic structures, the effect of variable amplitude (VA) loading is more pronounced due to large plastic zone sizes and crack growth retardation. On the other hand, to know about the fatigue life and crack growth in metals under VA loading, a number of prediction models have been developed [1]. These models ...
International Journal of Fatigue, 2011
This paper presents a study on the influence that load variations have on delamination shapes in ... more This paper presents a study on the influence that load variations have on delamination shapes in Fibre Metal Laminates. Previously fatigue tested centre-crack tension specimens have been chemically etched to obtain the final delamination shapes. In addition, fatigue crack growth tests on similar specimens have been performed to investigate the formation of delamination shapes. For this purpose, digital image correlation has been used as strain measurement technique to record the delamination shapes in situ testing. An explanation is put-forward in order to understand the effects of variable amplitude loading on the formation of delamination shapes. A transition in delamination shapes was observed, but evaluating this observation using an analytical fatigue crack growth prediction model including the observed change in delamination shapes revealed no significant effect on subsequent crack growth.
Fatigue & Fracture of Engineering Materials & Structures, 2009
To extend the predictive capability of existing crack growth models for fibre metal laminates und... more To extend the predictive capability of existing crack growth models for fibre metal laminates under constant amplitude fatigue loading to variable-amplitude loading, further research on variable-amplitude fatigue mechanisms in fibre metal laminates is necessary. In response to this need, an experimental study into the effects of multiple overloads, underloads and various block-loading sequences on crack growth in the fibre metal laminate Glare was investigated. Crack growth retardation effects were observed in the tests; however, the magnitude of these effects was lower than seen in monolithic aluminium because of fibre bridging. As a result, predictions of the observed behaviour were attempted using an existing constant-amplitude fatigue crack growth model for Glare in combination with a linear damage accumulation law. Keywords crack closure; crack growth; fatigue; fibre metal laminates; Glare; selective variable-amplitude fatigue. * Glare 3-3/2-0.3 is a laminate consisting of 3 aluminium layers with a thickness of 0.3 mm and 2 fibre layers both in 0 and 90 degrees. † Glare 4B-4/3-0.5 is a laminate consisting of 4 aluminium layers with a thickness of 0.5 mm and 3 fibre layers all in the directions 90/ 0/ 90 degrees.
Engineering Fracture Mechanics, 2010
This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal La... more This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal Laminates under variable amplitude fatigue loading. A recently developed constant amplitude analytical prediction model for Fibre Metal Laminates has been extended to predict fatigue crack growth under variable amplitude loading using the modified Wheeler model based on the Irwin crack-tip plasticity correction and effective stress intensity factor range (ΔKeff). The fatigue crack growth predictions made with this model have been ...
Composites Science and Technology, 2009
This paper presents the experimental and analytical investigation of the effect of variable ampli... more This paper presents the experimental and analytical investigation of the effect of variable amplitude (VA) load sequences on delamination behavior in Fibre Metal Laminates (FMLs). Delamination tests were performed and results are compared with linear damage accumulation predictions. Scanning Electronic Microscopy (SEM) was used to analyse the delaminated surfaces to study the delamination growth rate under VA loading in more detail. The correlation between test results and predictions highlighted the absence of load ...
Composites Science and Technology, 2009
Post-stretching is a potential method to change the unfavorable residual stress system in fibre m... more Post-stretching is a potential method to change the unfavorable residual stress system in fibre metal laminates (FMLs). During post-stretching of the material, the metal layers will be strained into the plastic region of the stress–strain curve, while the fibre layers remain elastic. After unloading, the residual stress system due to curing will be reduced or even reversed dependent on the amount of stretching. In the past, the classical laminate theory (CLT) has been modified, incorporating the thermal expansion for the application to FMLs. ...
A recently developed analytical prediction model for constant amplitude loading has been extended... more A recently developed analytical prediction model for constant amplitude loading has been extended to predict fatigue crack growth of Fibre Metal Laminates under variable amplitude loading. Accuracy of the model has been discussed in comparison with the experimental fatigue crack growth data.
KNAW Narcis. Back to search results. Publication Variable Amplitude Fatigue of FMLs On Developing... more KNAW Narcis. Back to search results. Publication Variable Amplitude Fatigue of FMLs On Developing a Mechanistic Understanding (2009) Open access. Pagina-navigatie: Main. ...
Computational and experimental analysis of damaged materials 2007, 2007
During the last decades, numerous papers have been published on fatigue life and fatigue crack gr... more During the last decades, numerous papers have been published on fatigue life and fatigue crack growth prediction under variable amplitude loading. The fatigue crack growth prediction models are fracture mechanics based models that have been developed to support the damage tolerance concepts in metallic structures.
Introduction Fiber Metal Laminates (FMLs) have been developed at Delft University of Technology (... more Introduction Fiber Metal Laminates (FMLs) have been developed at Delft University of Technology (TU Delft) as a robust and damage tolerant material concept for primary aircraft structures. Although successfully developed for fuselage skin structures, an increased interest is being observed to apply the concept to civil and military transport aircraft wing structures. ... A key characteristic of the FML concept is the high resistance against (fatigue) cracking and the significant residual strength in case of (fatigue) damage. This resistance enables designing structures with ...
KNAW Narcis. Back to search results. Publication Variable Amplitude Fatigue of FMLs On Developing... more KNAW Narcis. Back to search results. Publication Variable Amplitude Fatigue of FMLs On Developing a Mechanistic Understanding (2009) Open access. Pagina-navigatie: Main. ...
Engineering Fracture Mechanics, 2010
This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal La... more This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal Laminates under variable amplitude fatigue loading. A recently developed constant amplitude analytical prediction model for Fibre Metal Laminates has been extended to predict fatigue crack growth under variable amplitude loading using the modified Wheeler model based on the Irwin crack-tip plasticity correction and effective stress intensity factor range (ΔKeff). The fatigue crack growth predictions made with this model have been ...
Fatigue & Fracture of Engineering Materials & Structures, 2009
To extend the predictive capability of existing crack growth models for fibre metal laminates und... more To extend the predictive capability of existing crack growth models for fibre metal laminates under constant amplitude fatigue loading to variable-amplitude loading, further research on variable-amplitude fatigue mechanisms in fibre metal laminates is necessary. In response to this need, an experimental study into the effects of multiple overloads, underloads and various block-loading sequences on crack growth in the fibre metal laminate Glare was investigated. Crack growth retardation effects were observed in the tests; however, the magnitude of these effects was lower than seen in monolithic aluminium because of fibre bridging. As a result, predictions of the observed behaviour were attempted using an existing constant-amplitude fatigue crack growth model for Glare in combination with a linear damage accumulation law.
Engineering Fracture Mechanics, 2010
This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal La... more This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal Laminates under variable amplitude fatigue loading. A recently developed constant amplitude analytical prediction model for Fibre Metal Laminates has been extended to predict fatigue crack growth under variable amplitude loading using the modified Wheeler model based on the Irwin crack-tip plasticity correction and effective stress intensity factor range (ΔKeff). The fatigue crack growth predictions made with this model have been ...
Composites Science and Technology, 2009
Post-stretching is a potential method to change the unfavorable residual stress system in fibre m... more Post-stretching is a potential method to change the unfavorable residual stress system in fibre metal laminates (FMLs). During post-stretching of the material, the metal layers will be strained into the plastic region of the stress–strain curve, while the fibre layers remain elastic. After unloading, the residual stress system due to curing will be reduced or even reversed dependent on the amount of stretching. In the past, the classical laminate theory (CLT) has been modified, incorporating the thermal expansion for the application to FMLs. ...
Composites Science and Technology, 2009
This paper presents the experimental and analytical investigation of the effect of variable ampli... more This paper presents the experimental and analytical investigation of the effect of variable amplitude (VA) load sequences on delamination behavior in Fibre Metal Laminates (FMLs). Delamination tests were performed and results are compared with linear damage accumulation predictions. Scanning Electronic Microscopy (SEM) was used to analyse the delaminated surfaces to study the delamination growth rate under VA loading in more detail. The correlation between test results and predictions highlighted the absence of load ...
& Proceedings 저널· 프로시딩즈| 기술보고서| 해외연구초록| Reference DB| 공학설계| 부품규격| 항공우주특허| 원문신청| 논문스크랩| 연구자 DB 해외개발| 국내개발| 우주기술전략지도| AIAA 연차보고서| 저널번역| 일본항공우주| 국내연구성과| IP 제공정보| 부품개발현황 ARIC 용어사전| 교육도서| 인물사건| Web Link| 항공 우주 Spec 항공우주기사| 학술행사안내| 과제· 기관소식| 해외개발 소식| 뉴스레터 자유게시판| 오피니언| 실험실/업체 홍보| 갤러리, 2008
This paper presents the experimental and analytical research on the applicability of Linear Damag... more This paper presents the experimental and analytical research on the applicability of Linear Damage Accumulation Rule for fatigue crack growth in Fibre reinforced Metal Laminates under variable amplitude loading. A recently developed constant amplitude analytical prediction model has been extended to predict fatigue crack growth under variable amplitude loading using a linear damage accumulation rule. The modified model has been compared with crack growth tests on Fibre reinforced Metal Laminates centre-cracked ...
& Proceedings 저널· 프로시딩즈| 기술보고서| 해외연구초록| Reference DB| 공학설계| 부품규격| 항공우주특허| 원문신청| 논문스크랩| 연구자 DB 해외개발| 국내개발| 우주기술전략지도| AIAA 연차보고서| 저널번역| 일본항공우주| 국내연구성과| IP 제공정보| 부품개발현황 ARIC 용어사전| 교육도서| 인물사건| Web Link| 항공 우주 Spec 항공우주기사| 학술행사안내| 과제· 기관소식| 해외개발 소식| 뉴스레터 자유게시판| 오피니언| 실험실/업체 홍보| 갤러리, 2008
This paper presents the experimental and analytical research on the applicability of Linear Damag... more This paper presents the experimental and analytical research on the applicability of Linear Damage Accumulation Rule for fatigue crack growth in Fibre reinforced Metal Laminates under variable amplitude loading. A recently developed constant amplitude analytical prediction model has been extended to predict fatigue crack growth under variable amplitude loading using a linear damage accumulation rule. The modified model has been compared with crack growth tests on Fibre reinforced Metal Laminates centre-cracked tension specimen. In the end it is discussed to what extent or under what conditions the linear damage accumulation predictions are sufficiently accurate for Fibre reinforced Metal Laminates structures.
Collection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
This paper presents the experimental and analytical research on the applicability of Linear Damag... more This paper presents the experimental and analytical research on the applicability of Linear Damage Accumulation Rule for fatigue crack growth in Fibre reinforced Metal Laminates under variable amplitude loading. A recently developed constant amplitude analytical prediction model has been extended to predict fatigue crack growth under variable amplitude loading using a linear damage accumulation rule. The modified model has been compared with crack growth tests on Fibre reinforced Metal Laminates centre-cracked tension specimen. In the end it is discussed to what extent or under what conditions the linear damage accumulation predictions are sufficiently accurate for Fibre reinforced Metal Laminates structures.
Journal of Aircraft, 2009
FATIGUE is no doubt the main cause of failure in most load bearing components. The type of loadin... more FATIGUE is no doubt the main cause of failure in most load bearing components. The type of loading in nature is mainly based on variable amplitude which largely affects the severity and mechanisms of failure. In the case of metallic structures, the effect of variable amplitude (VA) loading is more pronounced due to large plastic zone sizes and crack growth retardation. On the other hand, to know about the fatigue life and crack growth in metals under VA loading, a number of prediction models have been developed [1]. These models ...
International Journal of Fatigue, 2011
This paper presents a study on the influence that load variations have on delamination shapes in ... more This paper presents a study on the influence that load variations have on delamination shapes in Fibre Metal Laminates. Previously fatigue tested centre-crack tension specimens have been chemically etched to obtain the final delamination shapes. In addition, fatigue crack growth tests on similar specimens have been performed to investigate the formation of delamination shapes. For this purpose, digital image correlation has been used as strain measurement technique to record the delamination shapes in situ testing. An explanation is put-forward in order to understand the effects of variable amplitude loading on the formation of delamination shapes. A transition in delamination shapes was observed, but evaluating this observation using an analytical fatigue crack growth prediction model including the observed change in delamination shapes revealed no significant effect on subsequent crack growth.
Fatigue & Fracture of Engineering Materials & Structures, 2009
To extend the predictive capability of existing crack growth models for fibre metal laminates und... more To extend the predictive capability of existing crack growth models for fibre metal laminates under constant amplitude fatigue loading to variable-amplitude loading, further research on variable-amplitude fatigue mechanisms in fibre metal laminates is necessary. In response to this need, an experimental study into the effects of multiple overloads, underloads and various block-loading sequences on crack growth in the fibre metal laminate Glare was investigated. Crack growth retardation effects were observed in the tests; however, the magnitude of these effects was lower than seen in monolithic aluminium because of fibre bridging. As a result, predictions of the observed behaviour were attempted using an existing constant-amplitude fatigue crack growth model for Glare in combination with a linear damage accumulation law. Keywords crack closure; crack growth; fatigue; fibre metal laminates; Glare; selective variable-amplitude fatigue. * Glare 3-3/2-0.3 is a laminate consisting of 3 aluminium layers with a thickness of 0.3 mm and 2 fibre layers both in 0 and 90 degrees. † Glare 4B-4/3-0.5 is a laminate consisting of 4 aluminium layers with a thickness of 0.5 mm and 3 fibre layers all in the directions 90/ 0/ 90 degrees.
Engineering Fracture Mechanics, 2010
This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal La... more This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal Laminates under variable amplitude fatigue loading. A recently developed constant amplitude analytical prediction model for Fibre Metal Laminates has been extended to predict fatigue crack growth under variable amplitude loading using the modified Wheeler model based on the Irwin crack-tip plasticity correction and effective stress intensity factor range (ΔKeff). The fatigue crack growth predictions made with this model have been ...
Composites Science and Technology, 2009
This paper presents the experimental and analytical investigation of the effect of variable ampli... more This paper presents the experimental and analytical investigation of the effect of variable amplitude (VA) load sequences on delamination behavior in Fibre Metal Laminates (FMLs). Delamination tests were performed and results are compared with linear damage accumulation predictions. Scanning Electronic Microscopy (SEM) was used to analyse the delaminated surfaces to study the delamination growth rate under VA loading in more detail. The correlation between test results and predictions highlighted the absence of load ...
Composites Science and Technology, 2009
Post-stretching is a potential method to change the unfavorable residual stress system in fibre m... more Post-stretching is a potential method to change the unfavorable residual stress system in fibre metal laminates (FMLs). During post-stretching of the material, the metal layers will be strained into the plastic region of the stress–strain curve, while the fibre layers remain elastic. After unloading, the residual stress system due to curing will be reduced or even reversed dependent on the amount of stretching. In the past, the classical laminate theory (CLT) has been modified, incorporating the thermal expansion for the application to FMLs. ...
A recently developed analytical prediction model for constant amplitude loading has been extended... more A recently developed analytical prediction model for constant amplitude loading has been extended to predict fatigue crack growth of Fibre Metal Laminates under variable amplitude loading. Accuracy of the model has been discussed in comparison with the experimental fatigue crack growth data.
KNAW Narcis. Back to search results. Publication Variable Amplitude Fatigue of FMLs On Developing... more KNAW Narcis. Back to search results. Publication Variable Amplitude Fatigue of FMLs On Developing a Mechanistic Understanding (2009) Open access. Pagina-navigatie: Main. ...
Computational and experimental analysis of damaged materials 2007, 2007
During the last decades, numerous papers have been published on fatigue life and fatigue crack gr... more During the last decades, numerous papers have been published on fatigue life and fatigue crack growth prediction under variable amplitude loading. The fatigue crack growth prediction models are fracture mechanics based models that have been developed to support the damage tolerance concepts in metallic structures.
Introduction Fiber Metal Laminates (FMLs) have been developed at Delft University of Technology (... more Introduction Fiber Metal Laminates (FMLs) have been developed at Delft University of Technology (TU Delft) as a robust and damage tolerant material concept for primary aircraft structures. Although successfully developed for fuselage skin structures, an increased interest is being observed to apply the concept to civil and military transport aircraft wing structures. ... A key characteristic of the FML concept is the high resistance against (fatigue) cracking and the significant residual strength in case of (fatigue) damage. This resistance enables designing structures with ...
KNAW Narcis. Back to search results. Publication Variable Amplitude Fatigue of FMLs On Developing... more KNAW Narcis. Back to search results. Publication Variable Amplitude Fatigue of FMLs On Developing a Mechanistic Understanding (2009) Open access. Pagina-navigatie: Main. ...
Engineering Fracture Mechanics, 2010
This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal La... more This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal Laminates under variable amplitude fatigue loading. A recently developed constant amplitude analytical prediction model for Fibre Metal Laminates has been extended to predict fatigue crack growth under variable amplitude loading using the modified Wheeler model based on the Irwin crack-tip plasticity correction and effective stress intensity factor range (ΔKeff). The fatigue crack growth predictions made with this model have been ...
Fatigue & Fracture of Engineering Materials & Structures, 2009
To extend the predictive capability of existing crack growth models for fibre metal laminates und... more To extend the predictive capability of existing crack growth models for fibre metal laminates under constant amplitude fatigue loading to variable-amplitude loading, further research on variable-amplitude fatigue mechanisms in fibre metal laminates is necessary. In response to this need, an experimental study into the effects of multiple overloads, underloads and various block-loading sequences on crack growth in the fibre metal laminate Glare was investigated. Crack growth retardation effects were observed in the tests; however, the magnitude of these effects was lower than seen in monolithic aluminium because of fibre bridging. As a result, predictions of the observed behaviour were attempted using an existing constant-amplitude fatigue crack growth model for Glare in combination with a linear damage accumulation law.
Engineering Fracture Mechanics, 2010
This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal La... more This paper presents the investigation regarding fatigue crack growth prediction in Fibre Metal Laminates under variable amplitude fatigue loading. A recently developed constant amplitude analytical prediction model for Fibre Metal Laminates has been extended to predict fatigue crack growth under variable amplitude loading using the modified Wheeler model based on the Irwin crack-tip plasticity correction and effective stress intensity factor range (ΔKeff). The fatigue crack growth predictions made with this model have been ...
Composites Science and Technology, 2009
Post-stretching is a potential method to change the unfavorable residual stress system in fibre m... more Post-stretching is a potential method to change the unfavorable residual stress system in fibre metal laminates (FMLs). During post-stretching of the material, the metal layers will be strained into the plastic region of the stress–strain curve, while the fibre layers remain elastic. After unloading, the residual stress system due to curing will be reduced or even reversed dependent on the amount of stretching. In the past, the classical laminate theory (CLT) has been modified, incorporating the thermal expansion for the application to FMLs. ...
Composites Science and Technology, 2009
This paper presents the experimental and analytical investigation of the effect of variable ampli... more This paper presents the experimental and analytical investigation of the effect of variable amplitude (VA) load sequences on delamination behavior in Fibre Metal Laminates (FMLs). Delamination tests were performed and results are compared with linear damage accumulation predictions. Scanning Electronic Microscopy (SEM) was used to analyse the delaminated surfaces to study the delamination growth rate under VA loading in more detail. The correlation between test results and predictions highlighted the absence of load ...
& Proceedings 저널· 프로시딩즈| 기술보고서| 해외연구초록| Reference DB| 공학설계| 부품규격| 항공우주특허| 원문신청| 논문스크랩| 연구자 DB 해외개발| 국내개발| 우주기술전략지도| AIAA 연차보고서| 저널번역| 일본항공우주| 국내연구성과| IP 제공정보| 부품개발현황 ARIC 용어사전| 교육도서| 인물사건| Web Link| 항공 우주 Spec 항공우주기사| 학술행사안내| 과제· 기관소식| 해외개발 소식| 뉴스레터 자유게시판| 오피니언| 실험실/업체 홍보| 갤러리, 2008
This paper presents the experimental and analytical research on the applicability of Linear Damag... more This paper presents the experimental and analytical research on the applicability of Linear Damage Accumulation Rule for fatigue crack growth in Fibre reinforced Metal Laminates under variable amplitude loading. A recently developed constant amplitude analytical prediction model has been extended to predict fatigue crack growth under variable amplitude loading using a linear damage accumulation rule. The modified model has been compared with crack growth tests on Fibre reinforced Metal Laminates centre-cracked ...
& Proceedings 저널· 프로시딩즈| 기술보고서| 해외연구초록| Reference DB| 공학설계| 부품규격| 항공우주특허| 원문신청| 논문스크랩| 연구자 DB 해외개발| 국내개발| 우주기술전략지도| AIAA 연차보고서| 저널번역| 일본항공우주| 국내연구성과| IP 제공정보| 부품개발현황 ARIC 용어사전| 교육도서| 인물사건| Web Link| 항공 우주 Spec 항공우주기사| 학술행사안내| 과제· 기관소식| 해외개발 소식| 뉴스레터 자유게시판| 오피니언| 실험실/업체 홍보| 갤러리, 2008
This paper presents the experimental and analytical research on the applicability of Linear Damag... more This paper presents the experimental and analytical research on the applicability of Linear Damage Accumulation Rule for fatigue crack growth in Fibre reinforced Metal Laminates under variable amplitude loading. A recently developed constant amplitude analytical prediction model has been extended to predict fatigue crack growth under variable amplitude loading using a linear damage accumulation rule. The modified model has been compared with crack growth tests on Fibre reinforced Metal Laminates centre-cracked tension specimen. In the end it is discussed to what extent or under what conditions the linear damage accumulation predictions are sufficiently accurate for Fibre reinforced Metal Laminates structures.