scholarly journals Coupled Hydrologic-Mechanical-Damage Analysis and Its Application to Diversion Tunnels of Hydropower Station

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Annan Jiang ◽  
Xiurong Yang ◽  
Mengfei Xu ◽  
Tengfei Jiang
Keyword(s):  
Damage Model ◽  
Differential Evolution Algorithm ◽  
Mechanical Damage ◽  
Damage Parameter ◽  
Damage Analysis ◽  
Analysis Program ◽  
Analysis Model ◽  
Coupling Problem ◽  
Elastoplastic Stress ◽  
Elastoplastic Damage

Since the traditional model cannot sufficiently reflect the multifield coupling problem, this paper established an elastoplastic stress-seepage-damage analysis model considering the seepage field, stress field, and damage field. Simultaneously, the elastoplastic damage model involves many parameters and is difficult to determine. An inverse analysis program is compiled based on the differential evolution algorithm, and the surrounding rock damage parameters are inverted. Finally, the elastoplastic stress-seepage-damage coupling program and the damage parameter displacement back analysis program is compiled using C++ language. Then, the program is used to calculate the coupling problem of tunnel elastoplastic stress-seepage-damage. The results show that the proposed elastoplastic damage constitutive model can well describe the mechanical behavior of rock. The computational procedure can also simulate practical engineering problems, which can provide specific guidance for site construction.

A Computational Model for Fe Ductile Plastic Damage Analysis of Plate Bending

1993 ◽  
Vol 60 (3) ◽  
pp. 749-758 ◽  
Author(s):  
Guangyu Shi ◽  
G. Z. Voyiadjis
Keyword(s):  
Computational Model ◽  
Stiffness Matrix ◽  
Damage Model ◽  
Strain Energy Release ◽  
Elastic Stiffness ◽  
Yield Function ◽  
Damage Effect ◽  
Damage Analysis ◽  
Plastic Damage ◽  
Elastoplastic Damage

This paper presents a computational model for the finite element plastic damage analysis of ductile flexural plates. The phenomenological damage model proposed by Lemaitre is adopted here. The damage effect parameters of a cross-section are defined and employed to account for the damage effect across the thickness of a bending plate. Similar to the effective stresses used in many damage models, the effective stress couples are introduced in this work and used in the yield function. The damage criterion is defined in terms of damage strain energy release rates. Based on the damage node model proposed here, the elastoplastic-damage stiffness matrix of element is derived. When the corresponding elastic stiffness matrix is given explicitly, the resulting elastoplastic-damage stiffness matrix can be evaluated without use of numerical integration. The feature of the expicit form of element stiffness matrix makes the computational model proposed here very efficient. Several numerical examples of ductile plastic damage analysis of plates are also given in this work to demonstrate the validity of the computational model.

scholarly journals Development of Elastoplastic-Damage Model of AlFeSi Phase for Aluminum Alloy 6061

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 954
Author(s):  
Hailong Wang ◽  
Wenping Deng ◽  
Tao Zhang ◽  
Jianhua Yao ◽  
Sujuan Wang
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Model ◽  
Material Properties ◽  
Damage Model ◽  
Scratch Test ◽  
Aluminum Alloy 6061 ◽  
Ultra Precision ◽  
Simulation Results ◽  
Alloy 6061 ◽  
Elastoplastic Damage

Material properties affect the surface finishing in ultra-precision diamond cutting (UPDC), especially for aluminum alloy 6061 (Al6061) in which the cutting-induced temperature rise generates different types of precipitates on the machined surface. The precipitates generation not only changes the material properties but also induces imperfections on the generated surface, therefore increasing surface roughness for Al6061 in UPDC. To investigate precipitate effect so as to make a more precise control for the surface quality of the diamond turned Al6061, it is necessary to confirm the compositions and material properties of the precipitates. Previous studies have indicated that the major precipitate that induces scratch marks on the diamond turned Al6061 is an AlFeSi phase with the composition of Al86.1Fe8.3Si5.6. Therefore, in this paper, to study the material properties of the AlFeSi phase and its influences on ultra-precision machining of Al6061, an elastoplastic-damage model is proposed to build an elastoplastic constitutive model and a damage failure constitutive model of Al86.1Fe8.3Si5.6. By integrating finite element (FE) simulation and JMatPro, an efficient method is proposed to confirm the physical and thermophysical properties, temperature-phase transition characteristics, as well as the stress–strain curves of Al86.1Fe8.3Si5.6. Based on the developed elastoplastic-damage parameters of Al86.1Fe8.3Si5.6, FE simulations of the scratch test for Al86.1Fe8.3Si5.6 are conducted to verify the developed elastoplastic-damage model. Al86.1Fe8.3Si5.6 is prepared and scratch test experiments are carried out to compare with the simulation results, which indicated that, the simulation results agree well with those from scratch tests and the deviation of the scratch force in X-axis direction is less than 6.5%.

A Damage Model Containing Delamination in Composite Laminates

2006 ◽  
Vol 324-325 ◽  
pp. 43-46
Author(s):  
Yu Pu Ma ◽  
Xin Zhi Lin ◽  
Qing Fen Li ◽  
Zhen Li
Keyword(s):  
Composite Laminates ◽  
Damage Model ◽  
Laminated Composite ◽  
Shear Lag ◽  
Analysis Model ◽  
Transverse Cracks ◽  
Transverse Cracking ◽  
Stiffness Reduction ◽  
Laminated Composite Materials ◽  
Modulus Reduction

When stress is high, delaminate damage can be induced by transverse cracks. A complete parabolic shear-lag damage model containing delamination induced by transverse cracks is therefore proposed and applied to predict the stiffness reduction by transverse cracking in cross-ply laminated composite materials. The predictions of the complete parabolic shear-lag analysis model, the incomplete parabolic shear-lag analysis model, and the complete parabolic shear-lag damage model containing delamination proposed in this paper have been compared. Results show that the young’s modulus reduction values obtained by our analysis model are better agreement with the experimental ones than other models.

A Rational Methodology for Determination of Service Life for a Delayed Coker Drum

2015 ◽  
Author(s):  
John J. Aumuller ◽  
Jie Chen ◽  
Vincent A. Carucci
Keyword(s):  
Service Life ◽  
Low Cycle Fatigue ◽  
Damage Model ◽  
Mechanical Damage ◽  
Damage Mechanism ◽  
Modern Trend ◽  
Cold Spot ◽  
Chromium Alloy ◽  
Cycle Fatigue ◽  
Service Environment

Delayed unit coker drums operate in a severe service environment that precludes long term reliability due to excessive shell bulging and cracking of shell joint and shell to skirt welds. Thermal fatigue is recognized as the leading damage mechanism and past work has provided an idealized description of the thermo-mechanical mechanism via local hot and cold spot formation to quantify a lower bound life estimate for shell weld failure. The present work extends this idealized thermo-mechanical damage model by evaluating actual field data to determine a potential upper bound life estimate. This assessment also provides insight into practical techniques for equipment operators to identify design and operational opportunities to extend the service life of coke drums for their specific service environments. A modern trend of specifying higher chromium and molybdenum alloy content for drum shell material in order to improve low cycle fatigue strength is seen to be problematic; rather, the use of lower alloy materials that are generally described as fatigue tough materials are better suited for the high strain-low cycle fatigue service environment of coke drums. Materials such as SA 204 C (C – ½ Mo) and SA 302 B (C – Mn – ½ Mo) or SA 302 C (C – Mn – ½ Mo – ½ Ni) are shown to be better candidates for construction in lieu of low chromium alloy steel materials such as SA 387 grades P11 (1¼ Cr – ½ Mo), P12 (1 Cr – ½ Mo), P22 (2¼ Cr – 1 Mo) and P21 (3 Cr – 1 Mo).

Multi-Scale Analysis Model of Thermal-Mechanical Damage Effect in High-Power Continuous-Wave Laser Irradiation of CFRP Laminates

2017 ◽  
Vol 44 (6) ◽  
pp. 0602003 ◽  
Author(s):  
赵伟娜 Zhao Weina ◽  
黄亿辉 Huang Yihui ◽  
宋宏伟 Song Hongwei ◽  
黄晨光 Huang Chenguang
Keyword(s):  
Continuous Wave ◽  
Mechanical Damage ◽  
Damage Effect ◽  
Scale Analysis ◽  
Continuous Wave Laser ◽  
Analysis Model ◽  
Cfrp Laminates ◽  
Multi Scale ◽  
Wave Laser ◽  
Multi Scale Analysis

scholarly journals A progressive damage model of textile composites on meso-scale using finite element method: static damage analysis

2013 ◽  
Vol 48 (25) ◽  
pp. 3091-3109 ◽  
Author(s):  
Jian Xu ◽  
Stepan Vladimirovitch Lomov ◽  
Ignaas Verpoest ◽  
Subbareddy Daggumati ◽  
Wim Van Paepegem ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Damage Model ◽  
Textile Composites ◽  
Progressive Damage ◽  
Damage Analysis ◽  
Progressive Damage Model ◽  
Meso Scale ◽  
Element Method

Numerical Prediction of Failure within Small Curvature Bending of Advanced High Strength Steels

2015 ◽  
Vol 639 ◽  
pp. 419-426
Author(s):  
Ioannis Tsoupis ◽  
Marion Merklein
Keyword(s):  
Crack Initiation ◽  
Damage Mechanics ◽  
Numerical Study ◽  
Damage Model ◽  
High Strength Steels ◽  
High Strength ◽  
Continuum Damage Mechanics ◽  
Calibration Method ◽  
Damage Parameter ◽  
Small Curvature

Within this paper a numerical study of the Continuum Damage Mechanics based damage model Lemaitre in commercial software LS-DYNA is performed in order to correctly predict failure in terms of crack occurrence within small curvature bending of AHSS steels. A strain based calibration method is used for the effective adaption of the Lemaitre model to the bending operation, which is based on the comparison and adaption of the numerically calculated and the experimentally measured deformation field on the outer surface of the bent specimen. Within this method the material dependent damage parameter S is systematically varied in the simulation in order to represent maximum major strain. The new method is proved by numerical simulation of experiments provoking crack initiation using smaller bending radii. It can be shown that failure in terms of crack initiation can be correctly predicted by the model with the damage parameters, which were determined by the method of strain based calibration and an additional optimisation of the parameter Dc. Thus, within this study a user friendly and effective way for the application of Lemaitre damage model to small curvature bending processes of AHSS steels is developed.

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