The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Michael F Petrou - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Behavior of carbon fiber reinforced polymer strengthened reinforced concrete bridge girders
Journal of Composites for Construction, 2004Co-Authors: John Aidoo, Kent A Harries, Michael F PetrouAbstract:This study examines the effects of one-dimensional fiber-reinforced polymer (FRP) composite rehabilitation systems on the flexural Fatigue performance of reinforced concrete bridge girders. Eight 508 mm deep and 5.6 m long reinforced concrete T-beams, with and without bonded FRP reinforcement on their tensile surfaces, were tested with a concentrated load at midspan under constant amplitude cyclic loading. The objective of this investigation is to establish the effect that these repair systems have on the Fatigue Behavior and remaining life of the girders. Results indicate that the Fatigue Behavior of such retrofit beams is controlled by the Fatigue Behavior of the reinforcing steel. The Fatigue life of a reinforced concrete beam can be increased by the application of an FRP retrofit, which relieves some of the stress carried by the steel. The observed increase in Fatigue life, however, is limited by the quality of the bond between the carbon FRP and concrete substrate. Debonding, initiating at midspan and progressing to a support, is common and is driven partially by the crack distribution and shear deformations of the beam.
Ali Fatemi - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Behavior and predictive modeling of short fiber thermoplastic composites
Procedia Engineering, 2015Co-Authors: Ali Fatemi, Seyyedvahid Mortazavian, Abolhasan KhosrovanehAbstract:Abstract Cyclic deformation and Fatigue Behavior of two short fiber thermoplastic composites (SFTCs) under a number of loading and environmental conditions are investigates. The considered environmental effects include those of low and elevated temperatures as well as moisture (or water absorption). Fatigue Behavior is also explored under the action of non-zero mean stress (or R ratio) in addition to fully-reversed ( R = -1), as well as various cyclic loading frequencies. Material anisotropy and geometrical discontinuity effects (i.e. stress concentration) are other aspects considered in this study. Based on experimental observations and analysis, a number of analytical and empirical models are developed for predicting Fatigue Behavior under different conditions. Empirical equations are presented to characterize self-heating under cyclic loading. Tsai-Hill criterion is applied to account for the effect of fiber orientation on Fatigue life. Mean stress effect is corrected with several mean stress parameters and a shift factor of Arrhenius type is defined to characterize the effect of temperature on Fatigue life. Two methodologies are presented to estimate Fatigue properties based on tensile properties. Estimation of notched Fatigue Behavior based on smooth Fatigue Behavior is also presented.
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Fatigue Behavior and modeling of short fiber reinforced polymer composites a literature review
International Journal of Fatigue, 2015Co-Authors: Seyyedvahid Mortazavian, Ali FatemiAbstract:Abstract Applications of short fiber reinforced polymer composites (SFRPCs) have been rapidly increasing and most of the components made of these materials are subjected to cyclic loading. Therefore, their Fatigue Behavior and modeling have been of much interest in recent years. This literature review presents a broad review of the many factors influencing cyclic deformation, Fatigue Behavior, and damage development in SFRPCs. These include microstructural related effects as well as effects related to loading condition and their service environment. Microstructural related effects include those related to fiber length, content and orientation, surface treatment, and failure mechanisms. Cyclic deformation and softening, viscous characteristics, and dissipative response used to characterize and model their Fatigue damage Behavior and accumulation are discussed. The effects of stress concentrations and their gradient on Fatigue Behavior are also discussed, due to their significant influence. The effects related to the loading condition include mean stress effects which may be accompanied by cyclic creep, variable amplitude loading, and multiaxial stress effects. Since Fatigue Behavior is substantially influenced by the testing frequency with self-heating as the primary consequence of increased frequency, this effect is also investigated. Environmental effects considered include the effects of moisture content and temperature, as well as thermo-mechanical Fatigue Behavior. The effect of welded joints in manufactured components made of SFRPCs and Fatigue analysis and life estimation techniques used for such components are also included.
Denver Seely - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Behavior and failure mechanisms of direct laser deposited ti 6al 4v
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2016Co-Authors: Amanda J Sterling, Brian Torries, Nima Shamsaei, Scott M Thompson, Denver SeelyAbstract:Abstract In order for additive-manufactured parts to become more widely utilized and trusted in application, it is important to have their mechanical properties well-characterized and certified. The Fatigue Behavior and failure mechanisms of Ti–6Al–4V specimens fabricated using Laser Engineered Net Shaping (LENS), a Direct Laser Deposition (DLD) additive manufacturing (AM) process, are investigated in this study. A series of fully-reversed strain-controlled Fatigue tests is conducted on Ti–6Al–4V specimens manufactured via LENS in their as-built and heat-treated conditions. Scanning Electron Microscopy (SEM) is used to examine the fracture surfaces of Fatigue specimens to qualify the failure mechanism, crack initiation sites, and defects such as porosity. Due to the relatively high localized heating and cooling rates experienced during DLD, fabricated parts are observed to possess anisotropic microstructures, and thus, different mechanical properties than those of their traditionally-manufactured wrought counterparts. The Fatigue lives of the investigated LENS specimens were found to be shorter than those of wrought specimens, and porosity was found to be the primary contributor to these shorter Fatigue lives, with the exception of the heat-treated LENS samples. The presence of pores promotes more unpredictable Fatigue Behavior, as evidenced by data scatter. Pore shape, size, location, and number were found to impact the Fatigue Behavior of the as-built and annealed DLD parts. As porosity seems to be the main contributor to the Fatigue Behavior of DLD parts, it is important to optimize the manufacturing process and design parameters to minimize and control pore generation during the build.
John Aidoo - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Behavior of carbon fiber reinforced polymer strengthened reinforced concrete bridge girders
Journal of Composites for Construction, 2004Co-Authors: John Aidoo, Kent A Harries, Michael F PetrouAbstract:This study examines the effects of one-dimensional fiber-reinforced polymer (FRP) composite rehabilitation systems on the flexural Fatigue performance of reinforced concrete bridge girders. Eight 508 mm deep and 5.6 m long reinforced concrete T-beams, with and without bonded FRP reinforcement on their tensile surfaces, were tested with a concentrated load at midspan under constant amplitude cyclic loading. The objective of this investigation is to establish the effect that these repair systems have on the Fatigue Behavior and remaining life of the girders. Results indicate that the Fatigue Behavior of such retrofit beams is controlled by the Fatigue Behavior of the reinforcing steel. The Fatigue life of a reinforced concrete beam can be increased by the application of an FRP retrofit, which relieves some of the stress carried by the steel. The observed increase in Fatigue life, however, is limited by the quality of the bond between the carbon FRP and concrete substrate. Debonding, initiating at midspan and progressing to a support, is common and is driven partially by the crack distribution and shear deformations of the beam.
Seyyedvahid Mortazavian - One of the best experts on this subject based on the ideXlab platform.
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Fatigue Behavior and predictive modeling of short fiber thermoplastic composites
Procedia Engineering, 2015Co-Authors: Ali Fatemi, Seyyedvahid Mortazavian, Abolhasan KhosrovanehAbstract:Abstract Cyclic deformation and Fatigue Behavior of two short fiber thermoplastic composites (SFTCs) under a number of loading and environmental conditions are investigates. The considered environmental effects include those of low and elevated temperatures as well as moisture (or water absorption). Fatigue Behavior is also explored under the action of non-zero mean stress (or R ratio) in addition to fully-reversed ( R = -1), as well as various cyclic loading frequencies. Material anisotropy and geometrical discontinuity effects (i.e. stress concentration) are other aspects considered in this study. Based on experimental observations and analysis, a number of analytical and empirical models are developed for predicting Fatigue Behavior under different conditions. Empirical equations are presented to characterize self-heating under cyclic loading. Tsai-Hill criterion is applied to account for the effect of fiber orientation on Fatigue life. Mean stress effect is corrected with several mean stress parameters and a shift factor of Arrhenius type is defined to characterize the effect of temperature on Fatigue life. Two methodologies are presented to estimate Fatigue properties based on tensile properties. Estimation of notched Fatigue Behavior based on smooth Fatigue Behavior is also presented.
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Fatigue Behavior and modeling of short fiber reinforced polymer composites a literature review
International Journal of Fatigue, 2015Co-Authors: Seyyedvahid Mortazavian, Ali FatemiAbstract:Abstract Applications of short fiber reinforced polymer composites (SFRPCs) have been rapidly increasing and most of the components made of these materials are subjected to cyclic loading. Therefore, their Fatigue Behavior and modeling have been of much interest in recent years. This literature review presents a broad review of the many factors influencing cyclic deformation, Fatigue Behavior, and damage development in SFRPCs. These include microstructural related effects as well as effects related to loading condition and their service environment. Microstructural related effects include those related to fiber length, content and orientation, surface treatment, and failure mechanisms. Cyclic deformation and softening, viscous characteristics, and dissipative response used to characterize and model their Fatigue damage Behavior and accumulation are discussed. The effects of stress concentrations and their gradient on Fatigue Behavior are also discussed, due to their significant influence. The effects related to the loading condition include mean stress effects which may be accompanied by cyclic creep, variable amplitude loading, and multiaxial stress effects. Since Fatigue Behavior is substantially influenced by the testing frequency with self-heating as the primary consequence of increased frequency, this effect is also investigated. Environmental effects considered include the effects of moisture content and temperature, as well as thermo-mechanical Fatigue Behavior. The effect of welded joints in manufactured components made of SFRPCs and Fatigue analysis and life estimation techniques used for such components are also included.
