scholarly journals Simplified strategies based on damage mechanics for concrete under dynamic loading

2017 ◽  
Vol 375 (2085) ◽  
pp. 20160170 ◽  
Author(s):  
Jacky Mazars ◽  
Stéphane Grange
Keyword(s):  
Dynamic Loading ◽  
Damage Mechanics ◽  
Experimental Testing ◽  
Damage Model ◽  
Nonlinear Effects ◽  
Strain Rates ◽  
Efficient Tool ◽  
Strain Rate Effects ◽  
Beam Elements ◽  
Rate Effects

Based on previous work, the µ damage model has been designed to figure out the various damage effects in concrete correlated with monotonic and cyclic loading, including unilateral effects. Assumptions are formulated to simplify constitutive relationships while still allowing for a correct description of the main nonlinear effects. In this context, the paper presents an enhanced simplified finite-element description including a damage description, based on the use of multifibre beam elements and including strain rate effects. Applications show that such a strategy leads to an efficient tool to simulate dynamic loading at low, medium and high velocities. This article is part of the themed issue ‘Experimental testing and modelling of brittle materials at high strain rates’.

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).

Strain Rate Effects in Crushable Structural Foams

2007 ◽  
Vol 7-8 ◽  
pp. 231-236 ◽  
Author(s):  
Robert A.W. Mines
Keyword(s):  
Strain Rates ◽  
Foreign Object ◽  
Axial Deformation ◽  
Dynamic Data ◽  
Strain Rate Effects ◽  
The Core ◽  
Sandwich Construction ◽  
Rate Effects ◽  
New Generation ◽  
Structural Foams

Structural foams are used as cores in sandwich construction. In the application of foreign object impact loading of sandwich structures, the core will suffer dynamic multi axial deformation and crush. This means that experimental study is required for the crush behaviour of structural foams at various strain rates, and numerical simulation foam models need to be calibrated with dynamic data. A number of foams are considered, namely Divinycell PVC foam, Rohacell PMI foam and Alporas aluminium foam. Also, new generation metallic micro lattice structures are discussed

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.

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.

scholarly journals ADI 1050-6 Mechanical Behavior at Different Strain Rates and Temperatures

2018 ◽  
Vol 925 ◽  
pp. 196-202 ◽  
Author(s):  
Andrew Ruggiero ◽  
Gianluca Iannitti ◽  
Stefano Masaggia ◽  
Federico Vettore
Keyword(s):  
Strain Rate ◽  
Damage Mechanics ◽  
Damage Model ◽  
Stress Triaxiality ◽  
Continuum Damage Mechanics ◽  
Tensile Tests ◽  
Yield Function ◽  
Strain Rates ◽  
The Continuum

An experimental characterization of the austempered ductile iron ISO 17804/JS/1050-6/S was performed carrying out tensile tests under different strain rates, temperatures and stress triaxiality levels. Then, composing a yield function surface, a hardening relation, and a damage criterion, a constitutive model was developed to describe the salient features of the observed macroscopic response. In particular, the Mohr-Coulomb yield function was selected to account for the pressure effect observed on the yield surface. A new hardening relation was proposed in order to account for both strain rate and temperature effects. The Bonora’s damage model, developed in the framework of the continuum damage mechanics, was adopted to capture the failure condition under different stress triaxiality levels. The damage model was appropriately modified to account for the effect of strain rate and temperature on the failure strain.

Temperature and Strain Rate Effects on Tensile Strength and Inelastic Constitutive Relationship of Sn-Pb Solders

2003 ◽  
Vol 125 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Haruo Nose ◽  
Masao Sakane ◽  
Yutaka Tsukada ◽  
Hideo Nishimura
Keyword(s):  
Tensile Strength ◽  
Yield Stress ◽  
Stress Amplitude ◽  
Young Modulus ◽  
Constitutive Relationship ◽  
Strain Rates ◽  
Strain Rate Effects ◽  
Tension Tests ◽  
Rate Effects ◽  
Relationship Of

This paper describes the tensile strength and inelastic constitutive relationship of six types of Sn-Pb solders. Static tension tests were carried using 5Sn-95Pb, 10Sn-90Pb, 40Sn-60Pb, 60Sn-40Pb, 63Sn-37Pb, and 62Sn-36Pb-2Ag solders at the strain rates of 0.001–10.0%/s between temperatures of 313 K and 398 K. Strain rates faster than 2.0%/s were needed to obtain the time-independent Young modulus and yield stress of the solders. Tensile strength increased with increasing strain rates up to 10%/s. Parametric equations for predicting tensile strength, Young’s modulus and yield stress of Sn-Pb solders were developed as a function of temperature and Sn content. Plastic and creep constitutive equations were also proposed as a function of temperature and Sn content. The stress amplitude predicted by these equations agreed with the experimental results within ±2 MPa.

Influence of Strain Rate Effects on the Structure and Mechanical Properties of the Fully Austenitic High Mn Steels under Dynamic Impact Deformation

2016 ◽  
Vol 246 ◽  
pp. 39-42 ◽  
Author(s):  
Magdalena Jabłońska ◽  
Wojciech Moćko ◽  
Kinga Rodak ◽  
Rafał Michalik ◽  
Anna Śmiglewicz
Keyword(s):  
Mechanical Properties ◽  
Testing Machine ◽  
Dynamic Mechanical Properties ◽  
Hydraulic Testing ◽  
Austenitic Steels ◽  
Strain Rates ◽  
Strain Rate Effects ◽  
Wide Range ◽  
Rate Effects ◽  
Static And Dynamic Loading

The article presents the dynamic mechanical properties of two types of high manganese austenitic steels. The investigation were carried out for the wide range of strain rates from 1×10-4s-1 up to 4×103s-1 using servo-hydraulic testing machine and Hopkinson bar for the quasi-static and dynamic loading regime, respectively. The mechanical properties at different strain rates as well as the SEA indicator calculated were carried out on the base of the results of impact tests. In the next step, the microstructure of the steel after different deformation rate was observed and analyzed by light microscope in order to disclose a TWIP effect.

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