scholarly journals Calibration of Failure Criteria for Additively Manufactured Metallic Materials

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3442
Author(s):  
Grzegorz Socha
Keyword(s):  
Failure Criterion ◽  
Failure Strain ◽  
Pure Shear ◽  
Ductile Failure ◽  
Failure Criteria ◽  
Calibration Procedure ◽  
Metallic Materials ◽  
Ductile Materials ◽  
Failure Models

A new version of failure criterion for additively manufactured materials, together with simple and accurate calibration procedures, is proposed and experimentally verified in this paper. The proposition is based on void growth-based ductile failure models. The failure criterion for ductile materials proposed by Hancock–Mackenzie was calibrated using simple methods and accessories. The calibration procedure allows the determination of failure strain under pure shear. The method is accurate and simple due to the fact that it prevents strain localization disturbing stress distribution at the failure zone. The original criterion was modified to better suit the deformation behavior of additively manufactured materials. Examples of calibration of the original and modified failure criteria for additively manufactured 316L alloy steel is also given in this paper, along with analyses of the obtained results.

Ductile Failure Analyses for API X65 Pipes Based on Local Failure Criteria

2006 ◽  
Author(s):  
Chang-Kyun Oh ◽  
Yun-Jae Kim ◽  
Jong-Hyun Baek ◽  
Young-Pyo Kim ◽  
Woo-Sik Kim
Keyword(s):  
Experimental Data ◽  
Failure Criterion ◽  
Hydrostatic Stress ◽  
Stress Triaxiality ◽  
Ductile Failure ◽  
Failure Criteria ◽  
Local Failure ◽  
Defective Region ◽  
Api X65 Steel ◽  
X65 Steel

A local failure criterion for the API X65 steel is applied to predict ductile failure of full-scale API X65 pipes with simulated corrosion and gouge defects under internal pressure. The local failure criterion is the stress-modified fracture strain for the API X65 steel as a function of the stress triaxiality (defined by the ratio of the hydrostatic stress to the effective stress). Based on detailed FE analyses with the proposed local failure criteria, burst pressures of defective pipes are estimated and compared with experimental data. The Failure of corroded pipes is governed by local necking and plastic collapse in the defective region, rather than failure. For pipes with gouge defects, on the other hand, it is found that fracture is dominant. The predicted burst pressures are in good agreement with experimental data. Noting that an assessment equation against the gouge defect is not yet available, parametric study is performed, from which a simple equation is proposed to predict burst pressure for API X65 pipes with gouge defects.

DISCOVERING FAILURE CRITERIA OF COMPOSITES BY SPARSE IDENTIFICATION AND COMPRESSED SENSING

2021 ◽  
Author(s):  
FEI TAO ◽  
XIN LIU ◽  
HAODONG DU ◽  
WENBIN YU
Keyword(s):  
Compressed Sensing ◽  
Failure Criterion ◽  
Failure Criteria ◽  
Engineering Practice ◽  
The Past ◽  
Failure Data ◽  
Failure Models ◽  
Reliable Design ◽  
Fiber Modes ◽  
First World

A reliable design of a composite structure needs to consider the failure of the composites. Hashin failure criterion is one of the most popular phenomenological models in engineering practice due to its simplicity of application. Although remarkable success has been achieved from the Hashin failure criterion, it does not always fit the experimental results very well. Over the past few years, a few experimental failure data have been collected. It would be of interest to leverage the existing data to improve the prediction of failure criteria. In this paper, we proposed to apply a framework that combines sparse regression with compressed sensing to discover failure criteria from data. Following the phenomenological failure models, we divided the failure of composites into tensile and compressive fiber modes, tensile and compressive matrix modes. Two examples were studied with the proposed framework. The first example was presented to demonstrate the capability of the framework. The data was generated by the Hashin failure criterion and added various magnitudes of noise. The proposed framework was implemented to discover the failure criterion from the noised data. For the second example, the proposed method was used to discover failure criteria from the experimental data which are collected from the first world wide failure exercise (WWFE I). Both examples show that the proposed method can discover the failure criteria accurately.

Application of Stochastic Optimization Techniques at the Example of Ceramic Turbine Disks

1993 ◽  
Author(s):  
Hans A. Eschenauer ◽  
Thomas Vietor
Keyword(s):  
Stochastic Optimization ◽  
Ceramic Materials ◽  
Failure Criteria ◽  
Optimization Techniques ◽  
Metallic Materials ◽  
Optimal Layout ◽  
Ductile Materials ◽  
Stiffness Properties ◽  
Stochastic Optimization Problem ◽  
Turbine Disks

Abstract In comparison to metallic materials, ceramic materials are very brittle which has made a wide use of them difficult up to now. For this reason, stochastic failure criteria, which differ considerably from those of ductile materials, have to be formulated and calculated mathematically. Because of high specific elasticity and stiffness properties, the ceramics are suitable for the layout of rotating components with a high rotating velocity. In order to find the optimal layout of a component made of ceramic materials, a stochastic optimization problem has to be defined and solved. A ceramic turbine disk has been chosen to demonstrate the shape optimization and the application of the stochastic optimization. By means of the functional-efficient boundaries and the associated optimal contours of the component conventional ductile materials are compared with ceramics for this application example. Herewith, the range of application of the materials examined can be determined.

Kinematical Analysis of Slope Stability Using Triangular Slices Method

2008 ◽  
Vol 33-37 ◽  
pp. 1115-1122
Author(s):  
Yong Jian Zhu
Keyword(s):  
Limit Analysis ◽  
Failure Criterion ◽  
Failure Criteria ◽  
Soil Mass ◽  
Nonlinear Failure Criterion ◽  
Analysis Theory ◽  
Straight Line ◽  
Straight Lines ◽  
Limit Analysis Method

Conventional stability analysis of slopes is established on vertical slices with a linear Mohr-Coulomb (MC) failure criterion. In this paper, the soil mass of slopes is assumed to follow linear and nonlinear failure criteria. A new procedure is proposed for determination of stability factors of slopes using triangular slices within the framework of limit analysis method under plane strain condition. The potential sliding mass is divided into a series of triangular slices, rather than vertical slices as usual. Using a generalized tangential technique, the nonlinear failure criterion is simplified as a set of straight lines according to the linear MC failure criterion. The straight line is tangential to the curve of the nonlinear failure criterion. With a linear MC failure criterion, solutions to stability factors are determined by limit analysis theory, which agree well with the published solutions. With triangular slices method, a study is carried out to investigate the influences of nonlinear parameter on stability of the soil slope.

Assessment of Failure Modeling With Thinning Strain Criterion in LS-DYNA

2003 ◽  
Author(s):  
Ching-Shan Cheng
Keyword(s):  
Failure Criterion ◽  
Material Model ◽  
Failure Criteria ◽  
Material Failure ◽  
Strain Criterion ◽  
Element Analysis ◽  
Material Models ◽  
Ductile Materials ◽  
Failure Modeling ◽  
Nonlinear Nature

Element deletion based on various failure criteria has been implemented in commercial finite element analysis packages, e.g. LS-DYNA. However, due to the localized and nonlinear nature of the material failure, especially for the ductile materials, a good failure criterion needs to be robust for different mesh definitions and loading conditions. In the present work, the material model with enhanced failure criterion in LS-DYNA, material type 123 (MAT123), is investigated. The equations for determining the parameter of the thinning strain failure criterion are derived based on the assumptions that Yeh et al. [7] proposed. Simulations of different tests using MAT123 with the thinning strain at failure calculated show better correlation with the experimental results than the other material models examined.

Sign in / Sign up

Export Citation Format

Share Document