scholarly journals Temperature and Strain-Rate Effects on Deformation Mechanisms in Irradiated Stainless Steel

1994 ◽  
Vol 373 ◽  
Author(s):  
J. L. Brimhall ◽  
J. I. Cole ◽  
J. S. Vetrano ◽  
S. M. Bruemmer
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Room Temperature ◽  
Deformation Mode ◽  
Radiation Hardening ◽  
Strain Rates ◽  
Lower Yield ◽  
Strain Rate Effects ◽  
Rate Effects ◽  
Higher Temperature

AbstractAnalysis of the deformation microstructures in ion-irradiated stainless steel shows twinning to be the predominant deformation mode at room temperature. Dislocation channelling also occurs under slow strain rate conditions. Stresses required for twinning were calculated by the model of Venables and are compatible with observed yield stresses in neutron-irradiated material if loops are the principal twin source. Computation of the expected radiation hardening from the defect structure, based on a simple model, is consistent with yield strengths measured on neutron-irradiated steels. Lower yield stresses and greater thermal energy at 288°C lessen the probability of twinning and dislocation channeling becomes the primary deformation mode at the higher temperature. However, preliminary results show that some twinning does occur in the irradiated stainless steel even at the higher temperature when higher strain rates are used.

Compressive Strain Rate Effects of Concrete

1985 ◽  
Vol 64 ◽  
Author(s):  
P. H. Bischoff ◽  
S. H. Perry
Keyword(s):  
Strain Rate ◽  
Impact Loading ◽  
Maximum Stress ◽  
Compressive Strain ◽  
Plain Concrete ◽  
Strain Rates ◽  
Strain Rate Effects ◽  
Conflicting Evidence ◽  
Rate Effects ◽  
Microcrack Growth

ABSTRACTSince good constitutive laws are required to model correctly the behaviour of concrete under impact loading, it is necessary to determine the complete stress-strain response of concrete at varying strain rates. Conflicting evidence emerges about whether the critical compressive strain (defined as the strain observed at maximum stress) increases or decreases with an increasing strain rate. In this paper, a comprehensive description is given of the brittle fracture process for plain concrete under static and impact loading. The strain rate dependance of tensile microcrack growth is used to explain both the increase in strength and the increase in critical compressive strain that can occur at high strain rates. More extensive experimental results are required to determine the fundamental changes in behaviour that occur as the loading rate is increased and, thus, facilitate the development of a more precise failure model for concrete.

scholarly journals Strain rate effects on ultra high performance fiber reinforced concrete (UHP-FRC) with various fiber contents

2021 ◽  
Author(s):  
Sayed-Mohammad Banitabaei-Koupaei
Keyword(s):  
Reinforced Concrete ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Performance ◽  
Fiber Reinforced Concrete ◽  
Strain Rates ◽  
Fiber Reinforced ◽  
Strain Rate Effects ◽  
Rate Effects ◽  
High Performance Fiber

Ultra High Performance Fiber Reinforced Concrete (UHP-FRC) was introduced in the mid-1990s and has made striking advances in recent years. Ductal® is a UHP-FRC technology that offers a unique combination of characteristics including but, not limited to ductility, strength and durability, while providing highly moldable products with quality surfaces. Compressive strengths, and equivalent flexural strengths reach up to 200 and 40 MPa, respectively. UHP-FRC also shows an outstanding performance under dynamic loading in structures subjected to extreme loading conditions such as impact, earthquake and blast. Moreover, UHP-FRC indicates an optimized combination of properties for a specific application. Three series of tests including compression, indirect tension, and flexure were conducted under various strain rates from quasi-static to dynamic loading with low strain rates. The objective of this project is to enhance knowledge of strain rate effects on UHP-FRC with various fiber contents and to report Dynamic Increase Factor (DIF).

scholarly journals Strain rate effects on ultra high performance fiber reinforced concrete (UHP-FRC) with various fiber contents

2021 ◽  
Author(s):  
Sayed-Mohammad Banitabaei-Koupaei
Keyword(s):  
Reinforced Concrete ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Performance ◽  
Fiber Reinforced Concrete ◽  
Strain Rates ◽  
Fiber Reinforced ◽  
Strain Rate Effects ◽  
Rate Effects ◽  
High Performance Fiber

Ultra High Performance Fiber Reinforced Concrete (UHP-FRC) was introduced in the mid-1990s and has made striking advances in recent years. Ductal® is a UHP-FRC technology that offers a unique combination of characteristics including but, not limited to ductility, strength and durability, while providing highly moldable products with quality surfaces. Compressive strengths, and equivalent flexural strengths reach up to 200 and 40 MPa, respectively. UHP-FRC also shows an outstanding performance under dynamic loading in structures subjected to extreme loading conditions such as impact, earthquake and blast. Moreover, UHP-FRC indicates an optimized combination of properties for a specific application. Three series of tests including compression, indirect tension, and flexure were conducted under various strain rates from quasi-static to dynamic loading with low strain rates. The objective of this project is to enhance knowledge of strain rate effects on UHP-FRC with various fiber contents and to report Dynamic Increase Factor (DIF).

Numerical simulation of welding stresses and distortions under consideration of temporal and local changes of strain rate

2004 ◽  
Vol 120 ◽  
pp. 169-175
Author(s):  
R. Ossenbrink ◽  
H. Wohlfahrt ◽  
V. Michailov
Keyword(s):  
Numerical Simulation ◽  
Strain Rate ◽  
High Strain ◽  
Local Strain ◽  
Tensile Tests ◽  
Strain Rates ◽  
Current Yield ◽  
Strain Rate Effects ◽  
Rate Effects ◽  
High Influence

As a result of high temperature changing rates in the heat affected zone (HAZ) the elevated strain rates during welding may have a high influence of the yield stresses. Higher yield stresses as a result of high strain rates can be observed in hot tensile tests for several materials. A model has been developed and integrated in a multi-purpose FEA-program (ANSYS®) to investigate strain rate effects in numerical welding simulation. The routine calculates the current yield stress as a function of the local strain rates. The influence of the resulting stresses and distortions has been analyzed in comparative numerical welding simulations.

Susceptibility of Iron-Rich Fe-Al Alloys to Embrittlement by Hydrogen and Water

1994 ◽  
Vol 364 ◽  
Author(s):  
R. J. Lynch ◽  
L. A. Heldt
Keyword(s):  
Aluminum Alloys ◽  
Strain Rate ◽  
Al Alloys ◽  
Hydrogen Gas ◽  
Strain Rates ◽  
Moist Air ◽  
Environmental Sensitivity ◽  
Strain Rate Effects ◽  
Rate Effects

AbstractIron-rich Fe-Al alloys have been tensile tested in moist air and dry oxygen at a strain rate of 3.3×10−4 s−1. Moist air did not cause embrittlement until the composition reached 18-20% Al. Alloys with lower aluminum contents were embrittled when tested in hydrogen gas. The environmental sensitivity of these alloys was further investigated by examining the effects of strain rate on the ductility. For the most part, no significant strain rate effects were observed in the low aluminum alloys; strain rates of up to 3.3×10−1 s−1 were not fast enough to prevent embrittlement. In contrast, the ductility of Fe-35 at.% Al did increase with increasing strain rate in air and hydrogen; at a strain rate of 3.3×10−1 s−1 the elongations approached that of vacuum.

Serrated Flow in 316LN Austenitic Stainless Steel

2013 ◽  
Vol 455 ◽  
pp. 159-162 ◽  
Author(s):  
Zhi Qiang Xu ◽  
Yin Zhong Shen
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Strain Rate ◽  
Room Temperature ◽  
Flow Behavior ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Serrated Flow ◽  
Substitutional Solute

Serrated flow behavior of the 316LN austenitic stainless steel was investigated through tensile tests at initial strain rates of 2×10-5 to 10-4 s-1 at temperatures ranging from room temperature to 1048 K. Serrated flow occurred at room temperature and 6981048K at the strain rate of 2×10-4 s-1, as well as at temperatures of 623673 K at the strain rate of 2×10-5 s-1. Type A, A+B, C and E serrations appeared. The activation energy for the occurrence of serrated flow at high temperatures was about 327 kJ/mol. The dynamic strain aging caused by the interaction between substitutional solute Cr atoms and moving dislocations is considered as the mechanism of serrated flow at the temperatures higher than 973 K.

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