scholarly journals Effect of a shear modified Gurson model on damage development in a FSW tensile specimen

2009 ◽  
Vol 46 (3-4) ◽  
pp. 587-601 ◽  
Author(s):  
Kim Lau Nielsen ◽  
Viggo Tvergaard
Keyword(s):  
Tensile Specimen ◽  
Damage Development ◽  
Gurson Model

Application of Gurson Model to Different Constraint Specimens

2014 ◽  
Author(s):  
Daigo Watanabe ◽  
Kiminobu Hojo
Keyword(s):  
Flat Plate ◽  
Ductile Failure ◽  
Local Strain ◽  
Tensile Specimen ◽  
The Other ◽  
Model Parameters ◽  
Gurson Model ◽  
Round Bar ◽  
Optimization Parameters ◽  
Design Calculations

This paper introduces the application of Gurson model to simulate the ultimate ductile failure of three types of specimens with different constraints. Fracture tests were conducted using three kinds of notched round bar tensile specimens with different notch radii, a flat plate tensile specimen with a centered semielliptical surface flaw and a 1/2TCT specimen. Using the test results of the notched round bar tensile specimens, the Gurson model parameters were determined from the literatures, fracture observation and experimental design calculations. After fixing the Gurson parameters, they were applied to the flat plate tensile specimen and the 1/2TCT specimen model. As a. result Gurson model could simulate the fracture behavior of the flat plate with good accuracy, on the other hand there was a large difference with the test result of the CT specimen. In order to determine the Gurson model parameters universally and quickly, the blind optimization calculations were performed without arbitrariness. Three of five parameters were in the same order of the parameters by the 1st consideration and the others were in the different order. However the blind optimization parameters could show the similar simulation results of the fracture behaviors of the flat plate and 1TCT specimen as the 1st consideration parameters. The further investigation suggested the reason of the different behavior of the CT specimen model may be the different stress distribution, bending component dominant in the cracked ligament of the CT specimen from those of the other models. Additionally the accuracy of the local strain criteria according to ASME Sec. VIII Division 2 was confirmed.

Effect of Shape of Fiber Bundle on Damage Development of Woven Fabric Composities

2006 ◽  
Vol 55 (2) ◽  
pp. 224-229 ◽  
Author(s):  
Takao OTA ◽  
Hikaru YOSHIZUMI ◽  
Hirokazu TSUCHIHASHI ◽  
Takashi MATSUOKA ◽  
Kazuhiko SAKAGUCHI
Keyword(s):  
Fiber Bundle ◽  
Woven Fabric ◽  
Damage Development

Effect of Irradiance Level and Paclobutrazol on Reducation of Leaf Damage in Begonia × cheimantha

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 446d-446
Author(s):  
Beyounghan Yoon ◽  
Harvey J. Lang
Keyword(s):  
Day Treatment ◽  
Leaf Damage ◽  
Growth Retardants ◽  
Damage Development ◽  
Long Day ◽  
Leaf Chlorosis ◽  
Shade Cloth ◽  
Growing Conditions ◽  
Reduced Light ◽  
Shade Plants

Begonia × cheimantha (Christmas or Lorraine begonia) is a popular holiday crop in Europe, with certain cultivars having outstanding postharvest characteristics. Its commercial production in the southern United States has been limited by the occurrence of mottled leaf chlorosis and necrosis, apparently due to environmental stress. In this study, B. × cheimantha `Emma' was grown in the fall in a glass greenhouse at College Station, Texas, under either 0%, 60%, or 87% polyethylene shade cloth. Leaf chlorosis and necrosis was very severe on plants grown in full sun (≈650 mol·m–2·s–1), with slight chlorosis on plants under 60% shade. Plants under full sun, however, were more compact, flowered earlier, and had shorter peduncles with more flowers than those grown under shade. Reducing the vegetative long-day treatment period from 7 to 4 weeks had no effect on leaf damage development. Plants treated with paclobutrazol were shorter and had less leaf damage than untreated plants. Leaves of treated plants had a relatively higher concentration of soluble protein, chlorophyll, and enhanced activities of ascorbate peroxidase (AsA), dehydroascorbate (DHA) reductase, and monodehydro-ascorbate (MDHA) reductase than untreated plants. For Texas growing conditions, these preliminary studies indicate that B. × cheimantha should be grown under reduced light intensities, with excessive height and leaf damage being controlled with growth retardants such as paclobutrazol.

scholarly journals Mechanical properties, deformation and fracture mechanisms of bimodal Cu under tensile test

2021 ◽  
Vol 60 (1) ◽  
pp. 15-24
Author(s):  
Silu Liu ◽  
Yonghao Zhao
Keyword(s):  
Yield Strength ◽  
Grain Refinement ◽  
Volume Fraction ◽  
Shear Fracture ◽  
High Strength ◽  
Tensile Specimen ◽  
Deformation Mechanisms ◽  
Fracture Mechanisms ◽  
Fracture Angle ◽  
Area Reduction

Abstract Metals with a bimodal grain size distribution have been found to have both high strength and good ductility. However, the coordinated deformation mechanisms underneath the ultrafine-grains (UFGs) and coarse grains (CGs) still remain undiscovered yet. In present work, a bimodal Cu with 80% volume fraction of recrystallized micro-grains was prepared by the annealing of equal-channel angular pressing (ECAP) processed ultrafine grained Cu at 473 K for 40 min. The bimodal Cu has an optimal strength-ductility combination (yield strength of 220 MPa and ductility of 34%), a larger shear fracture angle of 83∘ and a larger area reduction of 78% compared with the as-ECAPed UFG Cu (yield strength of 410 MPa, ductility of 16%, shear fracture angle of 70∘, area reduction of 69%). Grain refinement of recrystallized micro-grains and detwinning of annealing growth twins were observed in the fractured bimodal Cu tensile specimen. The underlying deformation mechanisms for grain refinement and detwinning were analyzed and discussed.

Damage Development in Gray Cast Iron under Static Deformation

2003 ◽  
Vol 35 (6) ◽  
pp. 568-573 ◽  
Author(s):  
A. A. Lebedev ◽  
I. V. Makovetskii ◽  
V. P. Lamashevskii ◽  
N. L. Volchek
Keyword(s):  
Cast Iron ◽  
Gray Cast Iron ◽  
Static Deformation ◽  
Gray Cast ◽  
Damage Development

Cross-Ply Laminates under Static Three-Point Bending: A Numerical Development Model

2012 ◽  
Vol 498 ◽  
pp. 42-54 ◽  
Author(s):  
S. Benbelaid ◽  
B. Bezzazi ◽  
A. Bezazi
Keyword(s):  
Numerical Model ◽  
Damage Mechanics ◽  
Progressive Failure ◽  
Damage Model ◽  
Continuum Damage Mechanics ◽  
Failure Criteria ◽  
Continuum Damage ◽  
Damage Development ◽  
Element Analysis ◽  
Progressive Failure Analysis

This paper considers damage development mechanisms in cross-ply laminates using an accurate numerical model. Under static three points bending, two modes of damage progression in cross-ply laminates are predominated: transverse cracking and delamination. However, this second mode of damage is not accounted in our numerical model. After a general review of experimental approaches of observed behavior of laminates, the focus is laid on predicting laminate behavior based on continuum damage mechanics. In this study, a continuum damage model based on ply failure criteria is presented, which is initially proposed by Ladevèze. To reveal the effect of different stacking sequence of the laminate; such as thickness and the interior or exterior disposition of the 0° and 90° oriented layers in the laminate, an equivalent damage accumulation which cover all ply failure mechanisms has been predicted. However, the solution algorithm using finite element analysis which implements progressive failure analysis is summarized. The results of the numerical computation have been justified by the previous published experimental observations of the authors.

Transferability of the Gurson Damage Model Parameters with Charpy and Tensile Tests with Different Constrain Level

2009 ◽  
Vol 65 ◽  
pp. 19-31
Author(s):  
Ruben Cuamatzi-Melendez ◽  
J.R. Yates
Keyword(s):  
Strain Rate ◽  
Damage Model ◽  
Rolling Direction ◽  
Fracture Initiation ◽  
Tensile Tests ◽  
Model Parameters ◽  
Gurson Model ◽  
Finite Element Program ◽  
Element Program ◽  
Gurson's Model

Little work has been published concerning the transferability of Gurson’s ductile damage model parameters in specimens tested at different strain rates and in the rolling direction of a Grade A ship plate steel. In order to investigate the transferability of the damage model parameters of Gurson’s model, tensile specimens with different constraint level and impact Charpy specimens were simulated to investigate the effect of the strain rate on the damage model parameters of Gurson model. The simulations were performed with the finite element program ABAQUS Explicit [1]. ABAQUS Explicit is ideally suited for the solution of complex nonlinear dynamic and quasi–static problems [2], especially those involving impact and other highly discontinuous events. ABAQUS Explicit supports not only stress–displacement analyses but also fully coupled transient dynamic temperature, displacement, acoustic and coupled acoustic–structural analyses. This makes the program very suitable for modelling fracture initiation and propagation. In ABAQUS Explicit, the element deletion technique is provided, so the damaged or dead elements are removed from the analysis once the failure criterion is locally reached. This simulates crack growth through the microstructure. It was found that the variation of the strain rate affects slightly the value of the damage model parameters of Gurson model.

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