scholarly journals Cracking simulation-based cumulative fatigue damage assessment

2021 ◽  
Author(s):  
mah farag ◽  
Ramy El-kady ◽  
M Hammouda
Keyword(s):  
Experimental Data ◽  
Collective Behavior ◽  
Damage Assessment ◽  
Fatigue Cracks ◽  
Damage Model ◽  
Surface Cracks ◽  
Fatigue Lifetime ◽  
Variable Amplitude ◽  
Simulation Based ◽  
Cumulative Fatigue Damage

This work is an extension of applying a previously developed fracture mechanics cracking damage model to predict the fatigue lifetime of un-notched round specimens made of a ferrite-pearlite 0.4C-70/30 carbon steel in some cases of variable amplitude loading VAL. The model simulates the collective behavior of growing short fatigue cracks originating from the specimen surface roughness. Material grains of different phases, sizes and strengths are randomly distributed over the minimum circumference. Possible activities of surface cracks are predicted against loading cycles. Relevant published experimental data were utilized for comparison. The present predictions are in agreement with the corresponding experimental results.

A Method for the Analysis of the Growth of Short Fatigue Cracks

1995 ◽  
Vol 117 (4) ◽  
pp. 408-411 ◽  
Author(s):  
A. J. McEvily ◽  
Y.-S. Shin
Keyword(s):  
Experimental Data ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Cracks ◽  
Material Constant ◽  
Plastic Zone Size ◽  
Surface Cracks ◽  
Zone Size ◽  
Short Cracks

A method for the analysis of the fatigue crack growth rate for short cracks has been developed and is applied to the case of fatigue crack growth of short surface cracks in a 1045 carbon steel. The method entails three modifications to standard LEFM procedures. These modifications include the use of a material constant to bridge between smooth and cracked specimen behavior, consideration of the plastic zone size to crack length ratio, and incorporation of the development of crack closure. Comparisons are made between calculations based upon this approach and experimental data.

Cumulative Damage in Composites

1990 ◽  
Vol 112 (3) ◽  
pp. 358-361 ◽  
Author(s):  
H. A. Whitworth
Keyword(s):  
Experimental Data ◽  
Fatigue Damage ◽  
Stress Level ◽  
Present Model ◽  
Damage Model ◽  
Fatigue Loading ◽  
Damage Function ◽  
Epoxy Composites ◽  
Remaining Life ◽  
Cumulative Fatigue Damage

The problem of cumulative fatigue damage in composites is analyzed based upon the development of a phenomenological damage model. In this modeling, a damage function is defined based on the degradation of the residual stiffness and used to predict the remaining life of composite specimens subjected to dual stress level fatigue loading. Available experimental data for graphite/epoxy composites are compared with the predictions of the present model.

scholarly journals New Nonlinear Cumulative Fatigue Damage Model Based on Ecological Quality Dissipation of Materials

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hongsong Li ◽  
Yongbao Liu ◽  
Xing He ◽  
Wangtian Yin
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Fatigue Damage ◽  
Damage Model ◽  
Fatigue Loading ◽  
Ecological Quality ◽  
Aircraft Structures ◽  
Variable Amplitude ◽  
Fatigue Damage Accumulation ◽  
Cumulative Fatigue Damage

The failure of many aircraft structures and materials is caused by the accumulation of fatigue damage under variable-amplitude cyclic loading wherein the damage evolution of materials is complicated. Therefore, to study the cumulative fatigue damage of materials under variable-amplitude cyclic loading, a new nonlinear fatigue damage accumulation model is proposed based on the ecological quality dissipation of materials by considering the effects of load interaction and sequence. The proposed new model is validated by the test data obtained for three kinds of material under multilevel fatigue loading. Compared with the Miner model and Kwofie model, the proposed model can more effectively analyse the accumulative damage and predict fatigue life of different materials under variable-amplitude cyclic loading than others. The study provides a basis for predicting fatigue life accurately and determining reasonable maintenance periods of aircraft structures.

A novel non-linear cumulative fatigue damage model based on the degradation of material memory

2019 ◽  
Vol 29 (4) ◽  
pp. 610-625
Author(s):  
Jie Zhou ◽  
Hong-Zhong Huang ◽  
Miles V Barnhart ◽  
Guoliang Huang ◽  
Yan-Feng Li
Keyword(s):  
Experimental Data ◽  
Fatigue Damage ◽  
Residual Life ◽  
Damage Model ◽  
Loading History ◽  
Material Parameters ◽  
Life Estimation ◽  
Damage Models ◽  
Proposed Model ◽  
Cumulative Fatigue Damage

Many fatigue damage models have been investigated based on the S– N curve or modified S– N curve; however, a number of them require additional efforts to determine the material parameters or do not consider the loading history (loading interactions, loading sequences, loading levels, etc.). These limitations can result in extreme deviations for estimating the fatigue life in real-world scenarios. To address these limitations, a new fatigue damage model is developed based on the material memory, which can be described as the degradation of mechanical properties under cyclic loadings. Comparisons with three models are used to demonstrate the validity of the proposed model. Furthermore, four sets of experimental data under two-stress and four-stress levels are carried out to verify the validation of the proposed model, which improves the residual life estimation over the three existing models used for comparison.

scholarly journals Decentral Energy Generation Potential of Anaerobic Digestion of Black Water and Kitchen Refuse for Eco-District Planning

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2948
Author(s):  
Soufia Mohammadi ◽  
Pilar Monsalvete Álvarez de Uribarri ◽  
Ursula Eicker
Keyword(s):  
Experimental Data ◽  
Anaerobic Digestion ◽  
Energy Demand ◽  
Alternative Energy ◽  
Organic Substrate ◽  
Mass Balances ◽  
Waste Streams ◽  
Black Water ◽  
Alternative Energy Source ◽  
Simulation Based

Biogas technology is an important alternative energy source worldwide. Blackwater and kitchen refuse represent ideal waste streams for bioenergy recovery through anaerobic co-digestion. Modeling of the biokinetics of anaerobic digestion on several aspects, such as microbial activity, substrate degradation, and methane production, from co-digestion of black water (BW) and kitchen refuse (KR) was the objective of this research. A mathematical model was developed towards a simulation based on mass balances on biomass, the organic substrate, and biogas. The model was implemented in INSEL and experimental data from the literature were used for model validation. The study shows that the simulation results fit well with the experimental data. The energy consumption and generation potential of anaerobic co-digestion of BW and KR were calculated to investigate if the produced biogas could supply the digester’s energy demand. This study can be used to pre-design anaerobic digestion systems in eco-districts.

Modeling of Solder Fatigue Failure due to Ductile Damage

2010 ◽  
Vol 26 (4) ◽  
pp. N23-N27 ◽  
Author(s):  
K. Aluru ◽  
F.-L. Wen ◽  
Y.-L. Shen
Keyword(s):  
Numerical Study ◽  
Fatigue Cracks ◽  
Damage Model ◽  
Quantitative Information ◽  
Ductile Damage ◽  
Element Analysis ◽  
Cyclic Shear ◽  
Rate Dependent ◽  
Solder Fatigue ◽  
Temporal And Spatial

ABSTRACTA numerical study is undertaken to simulate failure of solder joint caused by cyclic shear deformation. A progressive ductile damage model is incorporated into the rate-dependent elastic-viscoplastic finite element analysis, resulting in the capability of simulating damage evolution and eventual failure through crack formation. It is demonstrated that quantitative information of fatigue life, as well as the temporal and spatial evolution of fatigue cracks, can be explicitly obtained.

TCAD simulations of non-irradiated and irradiated low-gain avalanche diodes and comparison with measurements

2022 ◽  
Vol 17 (01) ◽  
pp. C01022
Author(s):  
T. Croci ◽  
A. Morozzi ◽  
F. Moscatelli ◽  
V. Sola ◽  
G. Borghi ◽  
...  
Keyword(s):  
Experimental Data ◽  
High Energy Physics ◽  
Signal To Noise Ratio ◽  
Damage Model ◽  
Surface Damage ◽  
High Energy ◽  
Silicon Detectors ◽  
Avalanche Diodes ◽  
Silicon Sensors ◽  
Energy Physics

Abstract In this work, the results of Technology-CAD (TCAD) device-level simulations of non-irradiated and irradiated Low-Gain Avalanche Diode (LGAD) detectors and their validation against experimental data will be presented. Thanks to the intrinsic multiplication of the charge within these silicon sensors, it is possible to improve the signal to noise ratio thus limiting its drastic reduction with fluence, as it happens instead for standard silicon detectors. Therefore, special attention has been devoted to the choice of the avalanche model, which allows the simulation findings to better fit with experimental data. Moreover, a radiation damage model (called “New University of Perugia TCAD model”) has been fully implemented within the simulation environment, to have a predictive insight into the electrical behavior and the charge collection properties of the LGAD detectors, up to the highest particle fluences expected in the future High Energy Physics (HEP) experiments. This numerical model allows to consider the comprehensive bulk and surface damage effects induced by radiation on silicon sensors. By coupling the “New University of Perugia TCAD model” with an analytical model that describes the mechanism of acceptor removal in the multiplication layer, it has been possible to reproduce experimental data with high accuracy, demonstrating the reliability of the simulation framework.

Analysis and Numerical Simulation of no Reacting Swirling Flow by Using URANS Approach

2021 ◽  
Vol 57 ◽  
pp. 67-79
Author(s):  
Merouane Habib ◽  
Senouci Mohammed
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Swirling Flow ◽  
Navier Stokes ◽  
Governing Equations ◽  
Simulation Based ◽  
Classical Models ◽  
Recirculation Zones ◽  
Computational Fluid Dynamics Cfd ◽  
Volume Method

In this paper, we investigate the no-reacting swirling flow by using the numerical simulation based to the unsteady Reynolds-averaged Navier-Stokes approach. The numerical simulation was realized by using a computational fluid dynamics CFD code. The governing equations are solved by using the finite volume method with two classical models of turbulence K-epsilon and Shear Stress K-ω. The objective of this paper is therefore to evaluate the performance of the two models in predicting the recirculation zones in a swirled turbulent flow. The current models are validated by comparing the numerical results of the axial, radial and tangential velocities to the experimental data from literature.

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