scholarly journals Deformation and Damage Assessments of Two DP1000 Steels Using a Micromechanical Modelling Method

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 805
Author(s):  
Niloufar Habibi ◽  
Napat Vajragupta ◽  
Sebastian Münstermann
Keyword(s):  
Deformation Behavior ◽  
Phase Distribution ◽  
Biaxial Tension ◽  
Maximum Shear Stress ◽  
Strain Partitioning ◽  
Cracking Resistance ◽  
Micromechanical Modelling ◽  
Stress Criterion ◽  
Damage Initiation ◽  
Edge Cracking

Damage characterization and micromechanical modelling in dual-phase (DP) steels have recently drawn attention, since any changes in the alloying elements or process route strongly influence the microstructural features, deformation behavior of the phases, and damage to the micro-mechanisms, and subsequently the particular mechanical properties of the material. This approach can be used to stablish microstructure–properties relationships. For instance, the effects of local damage from shear cutting on edge crack sensitivity in the following deformation process can be studied. This work evaluated the deformation and damage behaviors of two DP1000 steels using a microstructure-based approach to estimate the edge cracking resistance. Phase fraction, grain size, phase distribution, and texture were analyzed using electron backscatter diffraction and secondary electron detectors of a scanning electron microscope and employed in 3D representative volume elements. The deformation behavior of the ferrite phase was defined using a crystal plasticity model, which was calibrated through nanoindentation tests. Various loading conditions, including uniaxial tension, equi-biaxial tension, plane strain tension, and shearing, along with the maximum shear stress criterion were applied to investigate the damage initiation and describe the edge cracking sensitivity of the studied steels. The results revealed that a homogenous microstructure leads to homogenous stress–strain partitioning, delayed damage initiation, and high edge cracking resistance.

Hot Compression Deformation Behavior of Spray-Formed AlSn20Cu Alloy

2021 ◽  
Vol 1035 ◽  
pp. 189-197
Author(s):  
Bao Ying Li ◽  
Bao Hong Zhu
Keyword(s):  
Constitutive Equation ◽  
Strain Rate ◽  
Deformation Behavior ◽  
Deformation Temperature ◽  
Phase Distribution ◽  
True Stress ◽  
Hot Compression ◽  
Test Machine ◽  
Hot Compression Deformation ◽  
Compression Deformation

The hot deformation behavior of spray-formed AlSn20Cu alloy during hot compression deformation was studied, and the constitutive equation of AlSn20Cu alloy was established. The samples of spray-formed AlSn20Cu alloy were compressed on Gleeble-3500 thermal simulation test machine. The error of the true stress caused by adiabatic heating effect in the experiment was corrected. The constitutive equation of spray-formed AlSn20Cu alloy could be represented by Zener-Hollomon parameter in a hyperbolic sine function. The results showed that the deformation temperatures and strain rates had a notable effect on the true stress of the alloy. At the identical deformation temperature, the true stress increased with the increase of strain rate. When the strain rate was constant, the stress decreased with the increase of deformation temperature. After hot compression deformation, the tin phase was elongated along the direction perpendicular to the compression axis with short strips and blocks. With the increase of deformation temperature and the decrease of strain rate, Sn phase distribution became more homogeneous.

Application of MgO Concrete in China Dongfeng Arch Dam Foundation

2010 ◽  
Vol 168-170 ◽  
pp. 1953-1956 ◽  
Author(s):  
Chang Li Chen ◽  
Cheng Shu Tang ◽  
Zhen Hua Zhao
Keyword(s):  
High Temperature ◽  
Deformation Behavior ◽  
Arch Dam ◽  
Observation Data ◽  
Concrete Technology ◽  
Cracking Resistance ◽  
Dam Foundation ◽  
Stable Level ◽  
Mgo Concrete

In order to find out the long-term deformation behavior of MgO concrete,the nearly 10 years prototype observation data of Dongfeng arch dam foundation is analyzed. The results show that the MgO concrete has excellent delayed micro-expansion character, and its long-term expansive deformation always tends to stable level without any trend to contraction or infinite expansion, and by adding appropriate MgO expanding agent which was calcined at some high temperature into concrete, the cracking resistance of the concrete is improved. It is an effective way to construct dams excellently, efficiently and economically by using MgO concrete technology.

scholarly journals A 3D progressive damage model for fatigue analysis of woven fabric composites

2018 ◽  
Author(s):  
DC Pham
Keyword(s):  
Fatigue Damage ◽  
Test Data ◽  
Damage Accumulation ◽  
Damage Model ◽  
Peak Load ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Stress Criterion ◽  
Damage Initiation ◽  
Fatigue Damage Accumulation

A new 3D damage model is developed to predict the progressive failure and accumulated fatigue damage of woven fabric composite materials. Stress-based failure criteria are used to predict the damage initiation in x-tow, y-tow, and matrix constituent. An S-N based damage accumulation model is implemented to characterize the cycle dependent strength of the x- and y- fiber tows and matrix subjected to axial tension, compression, or in-plane share loading. A curve-fit non-linear shear model is also employed based on the static coupon test data of (+45/-45) woven fabric laminates. A static failure progression module is used to predict the damage and failure at the peak load prior to fatigue cycling. Stiffness degradation, fatigue damage accumulation, and failure mode detection are performed during the fatigue marching process. The developed user-defined material model for Abaqus features: 1) description of initial nonlinear shear before the damage initiation; 2) characterization of failure initiation based on a maximum stress criterion; and 3) performance of fatigue damage accumulation using a phenomenological model based on S-N test data. The predictive capabilities of the developed model are demonstrated using tension-tension fatigue of SYNCOGLAS R420 E-glass woven fabrics.

scholarly journals Effect of 3D Representative Volume Element (RVE) Thickness on Stress and Strain Partitioning in Crystal Plasticity Simulations of Multi-Phase Materials

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 944 ◽  
Author(s):  
Faisal Qayyum ◽  
Aqeel Afzal Chaudhry ◽  
Sergey Guk ◽  
Matthias Schmidtchen ◽  
Rudolf Kawalla ◽  
...  
Keyword(s):  
Grain Size ◽  
Crystal Plasticity ◽  
Deformation Behavior ◽  
Local Stress ◽  
Local Deformation ◽  
Volume Element ◽  
Stress And Strain ◽  
Strain Partitioning ◽  
Representative Volume ◽  
Multi Phase

Crystal plasticity simulations help to understand the local deformation behavior of multi-phase materials based on the microstructural attributes. The results of such simulations are mainly dependent on the Representative Volume Element (RVE) size and composition. The effect of RVE thickness on the changing global and local stress and strain is analyzed in this work for a test case of dual-phase steels in order to identify the minimal RVE thickness for obtaining consistent results. 100×100×100 voxel representative volume elements are constructed by varying grain size and random orientation distribution in DREAM-3D. The constructed RVEs are sliced in depth up to 1, 5, 10, 15, 20, 25, 30, 40, and 50 layers to construct different geometries with increasing thickness. Crystal plasticity model parameters for ferrite and martensite are taken from already published data and assigned to respective phases. Although the global stress/strain behavior of different RVEs is similar (<5% divergence), the local stress/strain partitioning in RVEs with varying thickness and grain size shows a considerable variation when statistically compared. It is concluded that two-dimensional (2D) RVEs can be used for crystal plasticity simulations when global deformation behavior is of interest. Whereas, it is necessary to consider three-dimensional (3D) RVEs, which have a specific thickness and number of grains for determining stabilized and more accurate local deformation behavior. This estimation will help researchers in optimizing the computation time for accurate mesoscale simulations.

Deformation behavior of commercially pure (CP) titanium under equi-biaxial tension

2016 ◽  
Vol 674 ◽  
pp. 540-551 ◽  
Author(s):  
Nedunchezhian Srinivasan ◽  
R. Velmurugan ◽  
Ravi Kumar ◽  
Satish Kumar Singh ◽  
Bhanu Pant
Keyword(s):  
Deformation Behavior ◽  
Biaxial Tension ◽  
Commercially Pure

The Effect of Strain Hardening in an Annular Slab

1953 ◽  
Vol 20 (4) ◽  
pp. 530-536
Author(s):  
P. G. Hodge
Keyword(s):  
Strain Hardening ◽  
Biaxial Tension ◽  
Complete Solution ◽  
Maximum Shear Stress ◽  
Strain Curve ◽  
Linear Strain ◽  
Stress Strain Curve ◽  
Line Segments ◽  
Straight Line ◽  
Strain Components

Abstract A procedure is outlined for obtaining the stresses and strains in a circular slab with a cutout, subject to uniform biaxial tension. An arbitrary stress-strain curve in tension is approximated by any number of straight-line segments. For biaxial states of stress the material is assumed to satisfy a flow law based on the maximum shear stress, and to be incompressible throughout. The general equations are given and then simplified by assuming that boundary motions may be neglected if the strains are small, and that elastic strain components may be neglected if the strains are large. For the case of linear strain hardening a complete solution is given in closed form. If the rate of strain hardening is small, these results may be simplified further.

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