A Phenomenological Model for Cyclic Plasticity

1997 ◽  
Vol 119 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Dar-Yun Chiang
Keyword(s):  
Cyclic Loading ◽  
Phenomenological Model ◽  
Material Properties ◽  
Experimental Studies ◽  
Cyclic Hardening ◽  
Analytical Models ◽  
Cyclic Plasticity ◽  
Loading Conditions ◽  
Microstructural Behavior ◽  
Distributed Elements

A phenomenological model is proposed for cyclic plasticity based on the concept of distributed elements, which is capable of reflecting microstructural behavior of real materials under multiaxial cyclic loading conditions. By investigating the detailed behavior of the model, various important phenomena and effects of materials in cyclic plasticity can be elucidated. Generalization of the model is also done to include cyclic hardening effects. A thorough understanding of these complicated response mechanisms and material properties provides useful insight and guidelines for validating analytical models and for performing experimental studies in the related areas of cyclic plasticity.

On the Modeling of Nonproportional Cyclic Plasticity of Waspaloy

1994 ◽  
Vol 116 (1) ◽  
pp. 35-44 ◽  
Author(s):  
A. Abdul-Latif ◽  
M. Clavel ◽  
V. Ferney ◽  
K. Saanouni
Keyword(s):  
Cyclic Loading ◽  
Kinematic Hardening ◽  
Experimental Tests ◽  
Point Of View ◽  
Cyclic Plasticity ◽  
Loading Path ◽  
Isotropic Hardening ◽  
Loading Conditions ◽  
Effective Role ◽  
Deformation Modes

The isotropic hardening is known to play an effective role in the overhardening of materials under nonproportional cyclic loading. However, the behavior of the two states of Waspaloy (namely overaged and underaged states) under these loading conditions, shows that the kinematic hardening has also a considerable role in the overhardening. Experimental tests were carried out on these two states under various proportional and nonproportional cyclic loading conditions at room temperature. The effect of loading paths on micro-mechanisms of deformation was studied. From a microstructural point of view, it was shown that the deformation modes (quantitatively and qualitatively) depend on the loading path and the heat treatment. A constitutive model is proposed to describe the effect of overhardening, under the nonproportional loading conditions, on the kinematic hardening. The predicted responses are in good agreement with experimental results.

Quantitative Evaluation of Dislocation Structure Induced by Cyclic Plasticity

2007 ◽  
Vol 345-346 ◽  
pp. 49-52 ◽  
Author(s):  
Tsuyoshi Mayama ◽  
Katsuhiko Sasaki ◽  
Yoshihiro Narita
Keyword(s):  
Cyclic Loading ◽  
Quantitative Evaluation ◽  
Strain Amplitude ◽  
Dislocation Structure ◽  
Evaluation Method ◽  
Cyclic Hardening ◽  
Cyclic Softening ◽  
Cyclic Plasticity ◽  
Loading Test ◽  
Loading Tests

In the present study, a new approach is conducted to evaluate dislocation structure induced by cyclic plasticity. First, cyclic plastic loading tests are carried out up to 100 cycles with three different small strain amplitudes on SUS316L stainless steel at room temperature. The test result presents the dependence of the strain amplitude on cyclic hardening and softening behaviors. Specifically, it is found that the cyclic loading test with strain amplitude of 0.25% shows both cyclic hardening and cyclic softening, while the cyclic loading tests with strain amplitudes of 0.75% and 1.0% show no cyclic softening. Secondly, the dislocation structures of the specimens after cyclic loading are observed by using a transmission electron microscope (TEM), and this observation reveals that the dislocation structure after cyclic loading test depends on the strain amplitude. Finally, a quantitative evaluation method of the dislocation structure is also proposed. The TEM images are converted into binary images and the resolution dependence of the generated binary image is used to visualize the characteristics of the dislocation structure. The relationship between strain amplitudes of cyclic plasticity and dislocation structure organization is clarified by the evaluation method. Finally, the heterogeneity of the dislocation structure is discussed.

Axial Capacity Evaluation for Typical Suspended Ceiling Joints

2016 ◽  
Vol 32 (1) ◽  
pp. 547-565 ◽  
Author(s):  
Siavash Soroushian ◽  
Manos Maragakis ◽  
Craig Jenkins
Keyword(s):  
Experimental Data ◽  
Cyclic Loading ◽  
Fragility Curves ◽  
Experimental Studies ◽  
Analytical Models ◽  
Seismic Fragility ◽  
Axial Capacity ◽  
Capacity Evaluation ◽  
Recent Earthquakes ◽  
The University

In recent earthquakes, the failure of nonstructural elements, including ceiling systems, has resulted in costly damage, inoperable buildings, and endangered lives. Therefore, the need to understand how ceiling systems perform during an earthquake is becoming increasingly important. However, few studies have been conducted on suspension ceiling systems to identify where they are vulnerable. A series of suspension-ceiling component experiments were designed at the University of Nevada, Reno, using interlocking grid members, including 2-ft. and 4-ft. cross tees. The test specimens were first subjected to monotonic and cyclic loading to obtain their failure capacities. Then several axial capacity fragility curves (not the seismic fragility curves of ceiling systems) were developed based on axial displacement capacities as well as strength capacities of interlocking ceiling joints in the absence of ceiling panels. Besides the experimental studies, a series of analytical models for ceiling joints were developed and validated using component experimental data.

scholarly journals Viscoplastic Parametric Analysis of Cylindrical Specimen Under Cyclic Behaviour

2021 ◽  
pp. 75-82
Author(s):  
Panagiotis J. Charitidis
Keyword(s):  
Cyclic Loading ◽  
Numerical Study ◽  
Kinematic Hardening ◽  
Cyclic Hardening ◽  
Material Model ◽  
Cyclic Plasticity ◽  
Axial Deformation ◽  
Cyclic Behaviour ◽  
Von Mises ◽  
Cyclic Plasticity Model

The present study tries to present a cyclic hardening model with the aim to simulate quantitatively the material response under strain controlled cyclic loading in tension-compression, of specified axial deformation. A numerical study was carried out to investigate the cyclic constitutive behaviour of alloy Indium under viscoplastic deformation. The analysis was performed under prescribed symmetric strain-controlled cyclic loading. The model contains both isotropic and kinematic hardening components, while the analysis were performed using Comsol Multiphysics for only 60 seconds duration. The kinematic hardening was described by using multiple back stresses. Multiple back stresses can provide a smoother transition between the elastic and plastic deformation, and it improves the general shape of the hysteresis loop. Two cases (geometries) have been examined in this study. From the material model and finite element cyclic plasticity model results, it is found that for the same parameters, but different dimensions there is difference on the stress-strain curves as well as on the von Mises stresses.

scholarly journals Experimental studies of profile joints of machine parts under cyclic loading conditions

2021 ◽  
pp. 24-28
Author(s):  
V. A. Ilyinykh ◽  
Keyword(s):  
Cyclic Loading ◽  
Experimental Studies ◽  
Loading Conditions ◽  
Active Materials ◽  
Tangential Stresses ◽  
Machine Parts ◽  
Critical Components ◽  
Flat Profile ◽  
Pulsation Cycle

The increasing demands on the quality of machines, in particular multipurpose CNC machines, determine the tasks aimed at improving the designs of their critical components. The aim of the work is to ensure the accuracy, contact rigidity and durability of torquetransmitting connections of spindle assemblies during reusable replacements of auxiliary tools based on the use of conical profile connections with an equiaxed contour. The paper presents the results of experimental studies of these compounds on models that are made of optically active materials, which allows us to visually study the processes of contact interaction of profile parts under cyclic loading conditions. The method of static photoelasticity in the study of flat profile joints with an equiaxed contour made it possible to establish based on the analysis of isochrome patterns, that the change in the values of maximum tangential stresses per revolution of the profile joint is subject to a pulsation cycle.

Numerical Simulation of CFRP Reinforced Steel Pipe Elbows Subjected to Cyclic Loading

2016 ◽  
Author(s):  
Giannoula Chatzopoulou ◽  
Ioannis Skarakis ◽  
Spyros A. Karamanos ◽  
Nicholas G. Tsouvalis ◽  
Aglaia E. Pournara
Keyword(s):  
Cyclic Loading ◽  
Structural Integrity ◽  
Mechanical Response ◽  
Numerical Models ◽  
Experimental Testing ◽  
Strain Curve ◽  
Steel Pipe ◽  
Cyclic Plasticity ◽  
Loading Conditions ◽  
Piping Systems

Strengthening of pipelines and piping systems under extreme loading conditions increases their operation safety level towards safeguarding their structural integrity. Motivated by the structural integrity of pipelines and piping systems, the present study aims at investigating the effect of Carbon Fiber Reinforced Plastic (CFRP) wrapping on the mechanical response of cyclically-loaded steel pipe elbows. Based on experimental testing results, a finite element model is developed, which simulates reinforced and non-reinforced pipe elbows specimens subjected to low-cyclic fatigue. For the description of the material nonlinearities, an efficient cyclic-plasticity material model is also employed, capable of describing both the yield plateau region of the steel stress-strain curve and the Bauschinger effect that appears under reverse plastic loading conditions. The results from the numerical models are compared successfully with the experimental data. Furthermore, a parametric analysis is conducted in order to examine the effect of internal pressure on the structural behavior of unreinforced and reinforced elbows, subjected to cyclic loading.

The uniaxial and biaxial, monotonic and cyclic plasticity behaviour of a lead alloy model material

1983 ◽  
Vol 18 (2) ◽  
pp. 125-133 ◽  
Author(s):  
T H Hyde
Keyword(s):  
Cyclic Loading ◽  
Cyclic Hardening ◽  
Model Material ◽  
Monotonic Loading ◽  
Biaxial Stress ◽  
Cyclic Plasticity ◽  
Lead Alloy ◽  
Material Behaviour ◽  
Loading Tests ◽  
Chill Cast

A chill-cast, antimony-arsenic-lead alloy model material has been used to investigate the monotonic and cyclic loading, uniaxial and biaxial plasticity behaviour of a metal at elevated temperature, i.e., T/ Tm ≈ 0.5. For the lead alloy used, a post-machining heat treatment of 96h at 100 C considerably reduced the scatter in the material behaviour. Uniaxial monotonic loading tests showed that the behaviour is relatively independent of temperature and strain-rate for strains less than about 1 per cent. Under cyclic loading conditions, between fixed strain limits, a stable hysteresis loop is obtained after the first cycle for both uniaxial and biaxial stress systems. By taking into account the biaxiality ratio and the increase in yield-range caused by cyclic hardening, the uniaxial and biaxial, cyclic plasticity behaviour was reasonably accurately predicted from the uniaxial, monotonic loading behaviour.

USE OF A NEW PHENOMENOLOGICAL MODEL TO CAPTURE THE NONLINEAR BEHAVIOR OF BRACING MEMBERS

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Mojtaba Farahi ◽  
Saeed Erfani
Keyword(s):  
Cyclic Loading ◽  
Phenomenological Model ◽  
Physical Theory ◽  
Nonlinear Behavior ◽  
Theory Model ◽  
Analytical Models ◽  
Non Linear ◽  
Lateral Bracing ◽  
Bracing System

This paper is a summary of an attempt to provide a phenomenological model in order to capture the nonlinear behavior of bracing members. The result obtained from modeling of a bracing system with the aid of the phenomenological model is compared with the result of a test to investigate the accuracy of the investigated model. Furthermore, static non-linear analyses are performed on an inverted V-braced subassembly using the phenomenological model as well as a convenient physical theory model. According to this study, the proposed phenomenological model is capable to favorably capture the behavior of a brace member under a cyclic loading. Hence, it can be used in analytical models of structural lateral bracing systems to assess accurately the nonlinear behavior of these systems.

scholarly journals CFRP Reinforcement and Repair of Steel Pipe Elbows Subjected to Severe Cyclic Loading

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Ioannis Skarakis ◽  
Giannoula Chatzopoulou ◽  
Spyros A. Karamanos ◽  
Nicholas G. Tsouvalis ◽  
Aglaia E. Pournara
Keyword(s):  
Cyclic Loading ◽  
Structural Integrity ◽  
Mechanical Response ◽  
Low Cycle Fatigue ◽  
Numerical Models ◽  
Strain Curve ◽  
Steel Pipe ◽  
Cyclic Plasticity ◽  
Loading Conditions ◽  
Element Analysis

In order to ensure safe operation and structural integrity of pipelines and piping systems subjected to extreme loading conditions, it is often necessary to strengthen critical pipe components. One method to strengthen pipe components is the use of composite materials. The present study is aimed at investigating the mechanical response of pipe elbows, wrapped with carbon fiber-reinforced plastic (CFRP) material, and subjected to severe cyclic loading that leads to low-cycle fatigue (LCF). In the first part of the paper, a set of LCF experiments on reinforced and nonreinforced pipe bend specimens are described focusing on the effects of CFRP reinforcement on the number of cycles to failure. The experimental work is supported by finite element analysis presented in the second part of the paper, in an attempt to elucidate the failure mechanism. For describing the material nonlinearities of the steel pipe, an efficient cyclic-plasticity material model is employed, capable of describing both the initial yield plateau of the stress–strain curve and the Bauschinger effect characterizing reverse plastic loading conditions. The results from the numerical models are compared with the experimental data, showing an overall good comparison. Furthermore, a parametric numerical analysis is conducted to examine the effect of internal pressure on the structural behavior of nonreinforced and reinforced elbows, subjected to severe cyclic loading.

Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

2020 ◽  
Vol 21 (5) ◽  
pp. 505
Author(s):  
Yousef Ghaderi Dehkordi ◽  
Ali Pourkamali Anaraki ◽  
Amir Reza Shahani
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Stress Relaxation ◽  
Stress Amplitude ◽  
Cyclic Plasticity ◽  
Mean Stress ◽  
Effective Parameters ◽  
Perfect Plasticity ◽  
Residual Stress Relaxation ◽  
Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

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