Investigation of Stress Stabilization Behavior of Type 316 Steel

2013 ◽  
Author(s):  
Mohammad R. Hormozi ◽  
Farid Biglari ◽  
Kamran M. Nikbin
Keyword(s):  
Low Cycle Fatigue ◽  
Direct Method ◽  
Kinematic Hardening ◽  
Experimental Investigations ◽  
Thermal Gradients ◽  
Element Analysis ◽  
Mechanical Fatigue ◽  
The Finite Element Analysis ◽  
A Direct Method ◽  
Strain Cycling

Some materials are designed to operate at high temperature environments with high thermal gradients and will be subject to thermal and mechanical cyclic strains. Under these cyclic temperatures and strains, thermo-mechanical fatigue (TMF) and low cycle fatigue (LCF) failure occur which will lead to the initiation of damage and cracking and subsequent crack growth. In this paper the numerical and experimental investigations of stress stabilization of 316FR steel subjected to strain cycling in the temperature range of 400–650 °C has been presented. The material exhibited both cyclic and nonlinear kinematic hardening behavior. In this paper the finite element analysis of cyclic loading of the materials was based on a direct method to use the test data from a stabilized cycle in combination with the hysteresis strain energy concept for damage derivation.

Prediction of thermo-mechanical fatigue life of IN738 LC using the finite element analysis

2014 ◽  
Vol 15 (8) ◽  
pp. 1733-1737 ◽  
Author(s):  
Jeong-Min Lee ◽  
Chang-Sung Seok ◽  
Dongkeun Lee ◽  
Yongseok Kim ◽  
Junghan Yun ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Element Analysis ◽  
Mechanical Fatigue ◽  
The Finite Element Analysis

scholarly journals On Creep Fatigue Interaction of Components at Elevated Temperature

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Daniele Barbera ◽  
Haofeng Chen ◽  
Yinghua Liu
Keyword(s):  
High Temperature ◽  
Mechanical Load ◽  
Direct Method ◽  
Bending Moment ◽  
Strain Range ◽  
Cyclic Plasticity ◽  
Element Analysis ◽  
Total Strain Range ◽  
Creep Fatigue ◽  
A Direct Method

The accurate assessment of creep–fatigue interaction is an important issue for industrial components operating with large cyclic thermal and mechanical loads. An extensive review of different aspects of creep fatigue interaction is proposed in this paper. The introduction of a high temperature creep dwell within the loading cycle has relevant impact on the structural behavior. Different mechanisms can occur, including the cyclically enhanced creep, the creep enhanced plasticity and creep ratchetting due to the creep fatigue interaction. A series of crucial parameters for crack initiation assessment can be identified, such as the start of dwell stress, the creep strain, and the total strain range. A comparison between the ASME NH and R5 is proposed, and the principal differences in calculating the aforementioned parameters are outlined. The linear matching method (LMM) framework is also presented and reviewed, as a direct method capable of calculating these parameters and assessing also the steady state cycle response due to creep and cyclic plasticity interaction. Two numerical examples are presented, the first one is a cruciform weldment subjected to cyclic bending moment and uniform high temperature with different dwell times. The second numerical example considers creep fatigue response on a long fiber reinforced metal matrix composite (MMC), which is subjected to a cycling uniform thermal field and a constant transverse mechanical load. All the results demonstrate that the LMM is capable of providing accurate solutions, and also relaxing the conservatisms of the design codes. Furthermore, as a direct method, it is more efficient than standard inelastic incremental finite element analysis.

Life Assessment of a Coke Drum by Using the Thermal-Mechanical Fatigue Properties and Laser Scanning Approach

2020 ◽  
Author(s):  
Zhiyuan Han ◽  
Guoshan Xie ◽  
Zengchao Wang ◽  
Jianzhong Yin ◽  
Jin Shi
Keyword(s):  
Fatigue Life ◽  
Laser Scanning ◽  
Low Cycle Fatigue ◽  
Complex Loading ◽  
Operating Conditions ◽  
Life Assessment ◽  
Fatigue Properties ◽  
Element Analysis ◽  
Thermal Mechanical Fatigue ◽  
Mechanical Fatigue

Abstract Coke drums are critical equipments in delayed coking plants, which are operated under severe thermal-mechanical conditions by cyclic heating and quenching processes. Cracks are usually developed during service because of severe plastic deformation and low-cycle fatigue. Thus, the assessment of the deformation severity and remaining life is important for safety operating of the coke drums. This study investigated the bulging damage and fatigue life of 6 coke drums after 16 years and 22 years of service in China. A thermal-mechanical fatigue test were first performed to simulate complex loading condition experienced by the coke drum. The thermal-mechanical fatigue life curve of the fabrication material was obtained. Then, a internal laser scanning was employed to measure the deformation and bulges of drum shells. The finite element analysis was developed to calculate the cyclic stress and strain and bulging severity based on the laser mapping and operating conditions. The fatigue life of the coke drum was assessed by the Coffin-Manson-Basquin’s relationship. The life evaluation results of different methods were compared and analyzed. The results showed that a reasonable life of the coke drum can be obtained by using the thermal-mechanical fatigue properties and laser scanning approach.

Evaluation on Thermo-Mechanical Fatigue Life of IN738LC Using Finite Element Analysis

2013 ◽  
Vol 467 ◽  
pp. 20-23
Author(s):  
Jeong Min Lee ◽  
Dong Keun Lee ◽  
Jae Mean Koo ◽  
Chang Sung Seok
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Strain Amplitude ◽  
Low Cycle Fatigue ◽  
Hysteresis Loops ◽  
Fatigue Tests ◽  
Plastic Strain Amplitude ◽  
Element Analysis ◽  
Mechanical Fatigue ◽  
Super Alloy

In this paper, thermo-mechanical fatigue tests were performed for the nickel-based super alloy IN738LC, after which the thermo-mechanical fatigue life was evaluated using finite element analysis. Nickel-based super alloy is used as the main material of turbine blades, which are important equipment in thermal power generation plants. In general, such materials receive three types of damage under thermo-mechanical fatigue loading. In the case of low-cycle fatigue behavior in which large plastic deformation mainly occurs, the lifetime can be decided by its relationship with the plastic strain amplitude. In order to obtain the plastic strain amplitude from the measured strain amplitude, a hysteresis loop should be derived. However, low-cycle fatigue tests are difficult. Moreover, precise experimental techniques are required to obtain the hysteresis loops. In this study, after thermo-mechanical fatigue tests were performed, thermal mechanical fatigue tests on IN738LC were simulated using finite element analysis. The results of analysis were verified by comparing with the hysteresis loops of an experiment

scholarly journals An Experimental Validation of Numerical Model for Top-Hat Tubular Structure Subjected to Axial Crush

2021 ◽  
Vol 11 (11) ◽  
pp. 4792
Author(s):  
Samer Fakhri Abdulqadir ◽  
Faris Tarlochan
Keyword(s):  
Experimental Data ◽  
Energy Absorption ◽  
Computational Models ◽  
Carbon Composite ◽  
Experimental Investigations ◽  
Ambient Conditions ◽  
Element Analysis ◽  
Axial Crush ◽  
The Finite Element Analysis ◽  
Vehicle Crashworthiness

Vehicle crashworthiness is an important aspect to consider when designing a vehicle to ensure the safety of the occupants. Besides this, vehicles are also designed to reduce weight for better fuel economics. One possible approach to reducing weight without compromising vehicle safety is by looking at new designs and usage of composite materials, along with the usage of computational models to reduce time and cost. Hence, this paper displays the experimental results of a carbon fiber reinforced closed top-hat section subjected to both quasi-static and dynamic crushing loading. The results were used to validate the computational model developed in the study. The specimens were made of carbon composite prepregs MTM-44 sheets stacked at the alternative orientation of ±45° and 0°/90°, where 0° direction coincides with the axis of the member. The samples were prepared by using a mold and carbon prepregs under vacuum bagging followed by curing in an autoclave. Trigger initiation was applied to ensure the specimens demonstrated a stable crushing mode of failure during the test. Experimental investigations were carried out under the ambient conditions with different loading conditions, and different kinetic energy ranges (2, 3 and 6 kJ). Experimental data was used to validate the finite element analysis (FEA). The maximum errors obtained between experimental and FEA for mean load, mean energy absorption, and crushing displacement were 13%, 13% and 7%, respectively. The numerically obtained results were in strong agreement with the experimental data and showed that they were able to predict the failure of the specimens. The work also showed the novelty of using such structures for energy absorption applications.

scholarly journals The application of Chaboche model in uniaxial ratcheting simulations

2020 ◽  
Vol 44 (2) ◽  
pp. 57-61
Author(s):  
Marta Wójcik ◽  
Andrzej Skrzat
Keyword(s):  
Kinematic Hardening ◽  
Strain Curve ◽  
Optimization Procedure ◽  
Least Square Method ◽  
Least Square ◽  
Compression Tests ◽  
Loading Test ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Chaboche Model

AbstractThis article presents the application of Chaboche nonlinear kinematic hardening model in simulations of uniaxial ratcheting. First, the symmetrical strain-controlled cyclic tension/compression tests for PA6 aluminum samples were done. Using the experimental stress–strain curve, initial material hardening parameters were determined by the ABAQUS software. The experimental curve was compared with the numerical one. For better fitting of both curves, the optimization procedure based on the least-square method was applied. Using the determined hardening parameters, numerical simulations of the ratcheting were done by the finite element analysis software. Numerical results were then compared with the experimental data obtained in the stress-controlled cyclic loading test.

Thermo Mechanical Fatigue Behaviour of Bare and Coated CMSX-4

2008 ◽  
Author(s):  
T. Coppola ◽  
S. Riscifuli ◽  
O. Tassa ◽  
G. Pasquero
Keyword(s):  
Low Cycle Fatigue ◽  
Turbine Blades ◽  
Fatigue Behaviour ◽  
Tensile Creep ◽  
Thermal Gradients ◽  
Test Program ◽  
Mechanical Fatigue ◽  
Complete Set ◽  
Comparison Of The Results ◽  
Very High

Highly cooled turbine blades undergo very high thermal gradients during rapid engine Idle-Max-Idle cycling. Traditional isothermal fatigue data are often insufficient for predicting service lives. A complete set of high temperature tests, in the range of 750 to 1050°C, was performed on single crystal alloy CMSX-4. The test program comprised tensile, creep, low cycle fatigue (LCF) and thermo-mechanical fatigue (TMF) tests. In particular the cycle time for TMF was 3 min., aiming to simulate the real high-power transient conditions in aircraft engines. Clockwise and counter-clockwise diamond cycle types were applied on bare and coated specimens to investigate their influence on the fatigue limit. The comparison of the results obtained with the available ones from open literature is discussed.

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