A Probabilistic Methodology for Random Stress-Strain Curves

1991 ◽  
Author(s):  
H. R. Millwater ◽  
S. V. Harren ◽  
B. H. Thacker
Keyword(s):  
Finite Element Analysis ◽  
Numerical Evaluation ◽  
General Procedure ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Behavior ◽  
Engineering Parameters ◽  
Analysis System

Abstract This paper presents a methodology for analyzing structures with random stress-strain behavior. Uncertainties in the stress-strain curve of a structure are simulated by letting a small number of engineering parameters which describe the stress-strain curve be random. Certain constraints are imposed on the engineering parameters in order to have a physically realizable material. A general procedure to handle correlation among the stress-strain parameters has also been developed. This methodology has been integrated into the NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) probabilistic structural analysis system. With this system, probabilistic finite element analysis of structures with random stress-strain behavior can be analyzed in an accurate, automated fashion. An example problem is presented to demonstrate the capabilities of the code. The problem analyzed is that of a pressure vessel fabricated with a material exhibiting random stress-strain behavior.

scholarly journals Non-linear finite element analysis of a Ti6Al4V/Inconel 625 joint obtained by explosion welding for sub-sea applications

2021 ◽  
Vol 38 (1) ◽  
pp. 13-16
Author(s):  
Pasqualino Corigliano
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Curve ◽  
Explosion Welding ◽  
Inconel 625 ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Element Analysis ◽  
Linear Finite Element ◽  
Non Linear

Industries have shown interest in the use of dissimilar metals to make corrosion-resistant materials combined with good mechanical properties in marine environments. Explosive welding can be considered a good method for joining dissimilar materials to prevent galvanic corrosion. The aim of the present study was to simulate the non-linear behaviour of a Ti6Al4V/Inconel 625 welded joint obtained by explosion welding from the values of the tensile ultimate strength and yielding strength of the parent materials. The present study compared the stress-strain curve from tensile loading obtained by the non-linear finite element analysis with the experimental stress-strain curve of a bimetallic joint. The applied method provides useful information for the development of models and the prediction of the structural behaviour of Ti6Al4V/Inconel 625 explosive welded joints.

scholarly journals Study on forging process and die design of parking sensor shell

2018 ◽  
Vol 185 ◽  
pp. 00020
Author(s):  
Tung-Sheng Yang ◽  
Jhong -Yuan Li
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Element Analysis ◽  
Forging Process ◽  
The Finite Element Analysis ◽  
Forging Force

The process of precision forging has been developed recently because of its advantages of giving high production rates and improved strength. For complete filling up, predicting the power requirement and final shape are important features of the forging process. A finite element method is used to investigate the forging force, the final shape and the stress distribution of the parking sensor shell forging. The stress-strain curve of AL-6082 is obtained by the computerized screw universal testing machine. The friction factor between AL-6082 alloy and die material (SKD11) are determined by using ring compression test. Stress-strain curve and fiction factor are then applied to the finite element analysis of the parking sensor shell forging. Maximum forging load, effective stress distribution and shape dimensions are determined of the parking sensor shell forging, using the finite element analysis. Then the parking sensor shells are formed by the forging machine. Finally, the experimental data are compared with the results of the current simulation for the forging force and shape dimensions of the parking sensor shell.

Numerical Study on the Mechanical Behavior of Aluminum Foam Material Using CT Image

2009 ◽  
Vol 79-82 ◽  
pp. 1297-1300 ◽  
Author(s):  
Hyup Jae Chung ◽  
Kyong Yop Rhee ◽  
Beom Suck Han ◽  
Yong Mun Ryu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Aluminum Foam ◽  
Three Dimensional ◽  
Strain Curve ◽  
Foam Material ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Element Analysis ◽  
X Ray

In this study, finite element analysis was made to predict the tensile and compressive behaviors of aluminum foam material. The predicted tensile and compressive behaviors were compared with those determined from the tensile and compressive tests. X-ray imaging technique was used to determine internal structure of aluminum foam material. That is, X-ray computed tomography (CT) was used to model the porosities of the material. Three-dimensional finite element modeling was made by stacking two-dimensional tomography of aluminum foam material determined from CT images. The stackings of CT images were processed by three-dimensional modeling program. The results showed that the tensile stress-strain curve predicted from the finite element analysis was similar to that determined by the experiment. The simulated compressive stress-strain curve also showed similar tendency with that of experiment up to about 0.4 strain but exhibited a different behavior from the experimental one after 0.4 strain. The discrepancy of compressive stress-strain curves in a high strain range was associated with the contact of aluminum foam walls broken by the large deformation.

Determination of Stress-Strain Curve for Microelectronic Solder Joint by ESPI Measurement and FE Analysis

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1983-1988
Author(s):  
Baik Woo Lee ◽  
Jeung Hyun Jeong ◽  
Woosoon Jang ◽  
Ju Young Kim ◽  
Dong Won Kim ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Properties ◽  
Thermal Deformation ◽  
Flip Chip ◽  
Computational Analysis ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Element Analysis

Many thermomechanical reliability studies on microelectronics and microsystems have relied upon computational analysis, since experimental work is rather difficult and very time-consuming. For computational analysis, it is essential to use as input accurate material properties; if not, the results of a reliability analysis may be very inaccurate. However, it is still quite difficult to arrive at unified material properties for modeling microelectronic assemblies because of the absence of standards for micro-material characterization, the difference between bulk and in-situ material properties, and so forth. The goal of this study was to determine the uniaxial stress-strain curve of a solder in a flip-chip assembly, using experimental measurements and finite-element analysis (FEA) of the solder's thermal deformation characteristics with increasing temperature. The thermal deformation of flip-chip solder joints was measured by electronic speckle pattern interferometry (ESPI). For the scale of evaluation required, the measurement magnification was modified to allow its application to micromaterials by using a long-working-distance microscope, iris and zoom lens. Local deformation of solder balls could be measured at submicrometer scale, and stress-strain curves could be determined using the measured thermal deformation as input data for finite-element analysis. The procedure was applied to an Sn-36Pb-2Ag flip-chip solder joint.

Understanding Dynamic Recrystallization Behavior through a Delay Differential Equation Approach

2007 ◽  
Vol 558-559 ◽  
pp. 441-448 ◽  
Author(s):  
Jong K. Lee
Keyword(s):  
Differential Equation ◽  
Strain Rate ◽  
Critical Strain ◽  
Strain Curve ◽  
Single Peak ◽  
Strain Rates ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strain Behavior ◽  
Delay Differential

During hot working, deformation of metals such as copper or austenitic steels involves features of both diffusional flow and dislocation motion. As such, the true stress-true strain relationship depends on the strain rate. At low strain rates (or high temperatures), the stress-strain curve displays an oscillatory behavior with multiple peaks. As the strain rate increases (or as the temperature is reduced), the number of peaks on the stress-strain curve decreases, and at high strain rates, the stress rises to a single peak before settling at a steady-state value. It is understood that dynamic recovery is responsible for the stress-strain behavior with zero or a single peak, whereas dynamic recrystallization causes the oscillatory nature. In the past, most predictive models are based on either modified Johnson-Mehl-Avrami kinetic equations or probabilistic approaches. In this work, a delay differential equation is utilized for modeling such a stress-strain behavior. The approach takes into account for a delay time due to diffusion, which is expressed as the critical strain for nucleation for recrystallization. The solution shows that the oscillatory nature depends on the ratio of the critical strain for nucleation to the critical strain for completion for recrystallization. As the strain ratio increases, the stress-strain curve changes from a monotonic rise to a single peak, then to a multiple peak behavior. The model also predicts transient flow curves resulting from strain rate changes.

Folding and Deployment of a New Thin-Walled Tube Flexible Hinge

2014 ◽  
Vol 635-637 ◽  
pp. 365-369 ◽  
Author(s):  
Hui Yang ◽  
Rong Qiang Liu ◽  
Hong Wei Guo ◽  
Jian Guo Tao
Keyword(s):  
Finite Element Analysis ◽  
Strain Curve ◽  
Tension Test ◽  
Slot Width ◽  
Stress Strain Curve ◽  
Element Analysis ◽  
Flexible Hinge ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Explicit Solver

A new thin-walled tube flexible hinge with six slots is proposed. The slot geometry is parameterized in terms of slot width, length and distance between two adjacent slots. The experiment for tension test of the thin-walled tube hinge with six-slots is conducted by INSTRON and the tensile stress-strain curve is measured. Finite element analysis to investigate the quasi-static folding and deployment of the new hinges by ABAQUS/Explicit solver are employed to perform a series of parameter studies for the slots longitude lengthl0, the slot widthwand the distancedbetween two adjacent slots.

scholarly journals Effects of layer shift and yarn path variability on mechanical properties of a twill weave composite

2016 ◽  
Vol 51 (7) ◽  
pp. 913-925 ◽  
Author(s):  
MY Matveev ◽  
AC Long ◽  
LP Brown ◽  
IA Jones
Keyword(s):  
Numerical Analysis ◽  
Strain Curve ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Element Analysis ◽  
Damage Propagation ◽  
Macro Scale ◽  
Twill Weave ◽  
Modulus Reduction ◽  
Good Agreement

Experimental and numerical analyses of a woven composite were performed in order to assess the effect of yarn path and layer shift variability on properties of the composite. Analysis of the geometry of a 12 K carbon fibre 2 × 2 twill weave at the meso- and macro-scales showed the prevalence of the yarn path variations at the macro-scale over the meso-scale variations. Numerical analysis of yarn path variability showed that it is responsible for a Young’s modulus reduction of 0.5% and CoV of 1% which makes this type of variability in the selected reinforcement almost insignificant for an elastic analysis. Finite element analysis of damage propagation in laminates with layer shift showed good agreement with the experiments. Both numerical analysis and experiments showed that layer shift has a strong effect on the shape of the stress–strain curve. In particular, laminates with no layer shift tend to exhibit a kink in the stress–strain curve which was attributed solely to the layer configuration.

Predictive Stress-Strain Models for High Strength Concrete Subjected to Uniaxial Compression

2014 ◽  
Vol 567 ◽  
pp. 476-481
Author(s):  
Nasir Shafiq ◽  
Tehmina Ayub ◽  
Muhd Fadhil Nuruddin
Keyword(s):  
Predictive Models ◽  
High Strength Concrete ◽  
Cement Content ◽  
Strain Curve ◽  
High Strength ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Strength Concrete ◽  
Strain Behavior ◽  
Four Cylinders

To date, various predictive models for high strength concrete (HSC) have been proposed that are capable of generating complete stress-strain curves. These models were validated for HSC prepared with and without silica fume. In this paper, an investigation on these predictive models has been presented by applying them on two different series of HSC. The first series of HSC was prepared by utilizing 100% cement content, while second series was prepared by utilizing 90% cement and 10% Metakaolin. The compressive strength of the concrete was ranged from 71-87 MPa. For each series of HSC, total four cylinders of the size 100×200mm were cast to obtain the stress-strain curves at 28 days.It has been found that the pattern of the stress-strain curve of each cylinder among four cylinders of each series was different from other, in spite of preparing from the similar batch. When predictive models were applied to these cylinders using their test data then it was found that all models more or less deficient to accurately predict the stress-strain behavior.

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