The Research on Modified Park-Ang Damage Model Based on Effective Energy Dissipation

2013 ◽  
Vol 742 ◽  
pp. 46-50
Author(s):  
Guo Fu ◽  
Bo Quan Liu
Keyword(s):  
Energy Dissipation ◽  
Structural Damage ◽  
Damage Model ◽  
Dissipation Factor ◽  
Mean Value ◽  
Economic Losses ◽  
Effective Energy ◽  
Load Path ◽  
Damage Models ◽  
Load Sequence

Collapse of buildings in earthquakes causes casualties and economic losses, the reinforced concrete columns damage models is a basis for the research of integer collapse. The major advantage of Park and Ang's method is the consideration of first exceedance failure and cumulative damage failure in terms of defining the structural damage under earthquake, however, it isn't consider the differences of structural failures by different displacement amplitudes and load sequence. By multiplying the effective energy dissipation factor and the load sequence factor, the modified Park-Ang seismic damage model is obtained. The comparison between the two models indicates that the modified Park-Ang model have mean value closer to 1 and smaller scatter, besides the effects of load path and load sequence on damage can be taken into account in the modified model.

scholarly journals Seismic Damage Model of Bridge Piers Subjected to Biaxial Loading Considering the Impact of Energy Dissipation

2019 ◽  
Vol 9 (7) ◽  
pp. 1481 ◽  
Author(s):  
Shangshun Lin ◽  
Zhanghua Xia ◽  
Jian Xia
Keyword(s):  
Energy Dissipation ◽  
Structural Damage ◽  
Biaxial Loading ◽  
Mechanical Performance ◽  
Damage Model ◽  
Damage Index ◽  
Seismic Damage ◽  
Bridge Piers ◽  
Dissipated Energy ◽  
The Impact

The large degradation of the mechanical performance of hollow reinforced concrete (RC) bridge piers subjected to multi-dimensional earthquakes has not been thoroughly assessed. This paper aims to improve the existing seismic damage model to assess the seismic properties of tall, hollow RC piers subjected to pseudo-static, biaxial loading. Cyclic bilateral loading tests on fourteen 1/14-scale pier specimens with different slenderness ratios, axial load ratios, and transverse reinforcement ratios were carried out to investigate the damage propagation and the cumulative dissipated energy with displacement loads. By considering the influence of energy dissipation on structural damage, a new damage model (M-Usami model) was developed to assess the damage characteristics of hollow RC piers. The results present four consecutive damage stages during the loading process: (a) cracking on concrete surface, (b) yielding of longitudinal reinforcements; (c) spalling of concrete, and (d) collapsing of pier after the concrete crushed and the longitudinal bars ruptured due to the flexural failure. The damage level caused by the seismic waves can be reduced by designing specimens with a good seismic energy dissipation capacity. The theoretical damage index values calculated by the M-Usami model agreed well with the experimental observations. The developed M-Usami model can provide insights into the approaches to assessing the seismic damage of hollow RC piers subjected to bilateral seismic excitations.

scholarly journals Improved numerical model for fatigue cumulative damage of mechanical structure considering load sequence and interaction

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199530
Author(s):  
Bixiong Huang ◽  
Shuci Wang ◽  
Shuanglong Geng ◽  
Xintian Liu
Keyword(s):  
Fatigue Life ◽  
Theoretical Basis ◽  
Life Prediction ◽  
Damage Model ◽  
Cumulative Damage ◽  
Load Spectrum ◽  
Random Load ◽  
Mechanical Parts ◽  
Proposed Model ◽  
Load Sequence

To more accurately predict the fatigue life of components under the action of random loads, it is necessary to explore the influence of the interaction between the load sequence and the load on the life prediction. Based on the Manson-Halford method and Corten-Dolan model, this paper establishes a fatigue cumulative damage model that takes into account both the load order and the interaction between loads, and also takes into account the loads near the fatigue limit. The fatigue life of mechanical parts under random load can be calculated through this model, which provides a theoretical basis for life prediction under random load spectrum. The fatigue life of mechanical parts under random load can be calculated through this model, which provides a theoretical basis for life prediction under random load spectrum. Comparing the calculation results of the proposed model with the results of Palmgren Miner, Manson-Halford method, and Corten-Dolan model, it is found that the fatigue damage model established can reasonably predict the fatigue life of parts. Comparison and verification of examples further prove the accuracy and reliability of the proposed model.

Failure Predictions for DP Steel Cross-die Test using Anisotropic Damage

2011 ◽  
Vol 21 (5) ◽  
pp. 713-754 ◽  
Author(s):  
M. S. Niazi ◽  
H. H. Wisselink ◽  
T. Meinders ◽  
J. Huétink
Keyword(s):  
Strain Rate ◽  
Damage Evolution ◽  
Damage Model ◽  
Anisotropic Damage ◽  
Continuum Damage ◽  
Anisotropic Plasticity ◽  
Continuum Damage Model ◽  
Damage Models ◽  
Isotropic Damage ◽  
Failure Predictions

The Lemaitre's continuum damage model is well known in the field of damage mechanics. The anisotropic damage model given by Lemaitre is relatively simple, applicable to nonproportional loads and uses only four damage parameters. The hypothesis of strain equivalence is used to map the effective stress to the nominal stress. Both the isotropic and anisotropic damage models from Lemaitre are implemented in an in-house implicit finite element code. The damage model is coupled with an elasto-plastic material model using anisotropic plasticity (Hill-48 yield criterion) and strain-rate dependent isotropic hardening. The Lemaitre continuum damage model is based on the small strain assumption; therefore, the model is implemented in an incremental co-rotational framework to make it applicable for large strains. The damage dissipation potential was slightly adapted to incorporate a different damage evolution behavior under compression and tension. A tensile test and a low-cycle fatigue test were used to determine the damage parameters. The damage evolution was modified to incorporate strain rate sensitivity by making two of the damage parameters a function of strain rate. The model is applied to predict failure in a cross-die deep drawing process, which is well known for having a wide variety of strains and strain path changes. The failure predictions obtained from the anisotropic damage models are in good agreement with the experimental results, whereas the predictions obtained from the isotropic damage model are slightly conservative. The anisotropic damage model predicts the crack direction more accurately compared to the predictions based on principal stress directions using the isotropic damage model. The set of damage parameters, determined in a uniaxial condition, gives a good failure prediction under other triaxiality conditions.

scholarly journals From damage models to SIR epidemics and cascading failures

2009 ◽  
Vol 41 (1) ◽  
pp. 247-269 ◽  
Author(s):  
Maude Gathy ◽  
Claude Lefèvre
Keyword(s):  
Branching Process ◽  
Damage Model ◽  
Exact Distribution ◽  
Partial Sums ◽  
Mathematical Tool ◽  
Close Approximation ◽  
Final Size ◽  
Damage Models ◽  
Starting Point ◽  
Made In

This paper is concerned with a nonstationary Markovian chain of cascading damage that constitutes an iterated version of a classical damage model. The main problem under study is to determine the exact distribution of the total outcome of this process when the cascade of damages finally stops. Two different applications are discussed, namely the final size for a wide class of SIR (susceptible → infective → removed) epidemic models and the total number of failures for a system of components in reliability. The starting point of our analysis is the recent work of Lefèvre (2007) on a first-crossing problem for the cumulated partial sums of independent parametric distributions, possibly nonstationary but stable by convolution. A key mathematical tool is provided by a nonstandard family of remarkable polynomials, called the generalised Abel–Gontcharoff polynomials. Somewhat surprisingly, the approach followed will allow us to relax some model assumptions usually made in epidemic theory and reliability. To close, approximation by a branching process is also investigated to a certain extent.

scholarly journals Large-scale application of the flood damage model RAilway Infrastructure Loss (RAIL)

2016 ◽  
Vol 16 (11) ◽  
pp. 2357-2371 ◽  
Author(s):  
Patric Kellermann ◽  
Christine Schönberger ◽  
Annegret H. Thieken
Keyword(s):  
Risk Management ◽  
Risk Aversion ◽  
Flood Risk ◽  
Structural Damage ◽  
Large Scale ◽  
Damage Model ◽  
Flood Damage ◽  
Railway Infrastructure ◽  
Increased Risk ◽  
The Impact

Abstract. Experience has shown that river floods can significantly hamper the reliability of railway networks and cause extensive structural damage and disruption. As a result, the national railway operator in Austria had to cope with financial losses of more than EUR 100 million due to flooding in recent years. Comprehensive information on potential flood risk hot spots as well as on expected flood damage in Austria is therefore needed for strategic flood risk management. In view of this, the flood damage model RAIL (RAilway Infrastructure Loss) was applied to estimate (1) the expected structural flood damage and (2) the resulting repair costs of railway infrastructure due to a 30-, 100- and 300-year flood in the Austrian Mur River catchment. The results were then used to calculate the expected annual damage of the railway subnetwork and subsequently analysed in terms of their sensitivity to key model assumptions. Additionally, the impact of risk aversion on the estimates was investigated, and the overall results were briefly discussed against the background of climate change and possibly resulting changes in flood risk. The findings indicate that the RAIL model is capable of supporting decision-making in risk management by providing comprehensive risk information on the catchment level. It is furthermore demonstrated that an increased risk aversion of the railway operator has a marked influence on flood damage estimates for the study area and, hence, should be considered with regard to the development of risk management strategies.

scholarly journals Extension of Flow Behaviour and Damage Models for Cast Iron Alloys with Strain Rate Effect

2020 ◽  
Author(s):  
Chuang Liu ◽  
Dongzhi Sun ◽  
Xianfeng Zhang ◽  
Florence Andrieux ◽  
Tobias Gerster
Keyword(s):  
Cast Iron ◽  
Constitutive Model ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Damage Model ◽  
Iron Alloys ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Damage Models ◽  
Rate Dependent

Abstract Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive industry. To study the mechanical behavior of a typical ductile cast iron (GJS-450) with nodular graphite, uni-axial quasi-static and dynamic tensile tests at strain rates of 10− 4, 1, 10, 100, and 250 s− 1 were carried out. In order to investigate the effects of stress state, specimens with various geometries were used in the experiments. Stress–strain curves and fracture strains of the GJS-450 alloy in the strain-rate range of 10− 4 to 250 s− 1 were obtained. A strain rate-dependent plastic flow law based on the Voce model is proposed to describe the mechanical behavior in the corresponding strain-rate range. The deformation behavior at various strain rates is observed and analyzed through simulations with the proposed strain rate-dependent constitutive model. The available damage model from Bai and Wierzbicki is extended to take the strain rate into account and calibrated based on the analysis of local fracture strains. The validity of the proposed constitutive model including the damage model was verified by the corresponding experimental results. The results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 alloys. The predictions with the proposed constitutive model and damage models at various strain rates agree well with the experimental results, which illustrates that the rate-dependent flow rule and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain rates.

scholarly journals Identification of Structural Damage in Bridges Using High-Frequency Vibrational Responses

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ivana Mekjavić
Keyword(s):  
High Frequency ◽  
Structural Damage ◽  
Natural Frequencies ◽  
Damage Identification ◽  
Damage Model ◽  
Reinforced Concrete Beam ◽  
Computational Technique ◽  
Damage Scenarios ◽  
Identification Approach ◽  
Girder Bridge

The present research aims to develop an effective and applicable structural damage detection method. A damage identification approach using only the changes of measured natural frequencies is presented. The structural damage model is assumed to be associated with a reduction of a contribution to the element stiffness matrix equivalent to a scalar reduction of the material modulus. The computational technique used to identify the damage from the measured data is described. The performance of the proposed technique on numerically simulated real concrete girder bridge is evaluated using imposed damage scenarios. To demonstrate the applicability of the proposed method by employing experimental measured natural frequencies this technique is applied for the first time to a simply supported reinforced concrete beam statically loaded incrementally to failure. The results of the damage identification procedure show that the proposed method can accurately locate the damage and predict the extent of the damage using high-frequency (here beyond the 4th order) vibrational responses.

Comparison of Two Damage Models for Prediction of Failure in Stress Corrosion Cracking

2018 ◽  
Author(s):  
Sorabh Singhal ◽  
Yogeshwar Jasra ◽  
Ravindra K. Saxena
Keyword(s):  
Crack Initiation ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Driving Force ◽  
Damage Mechanics ◽  
Damage Model ◽  
Corrosion Cracking ◽  
Force Model ◽  
Initiation Time ◽  
Damage Models

In the present work, Stress corrosion cracking (SCC) and its mechanical behavior are presented. SCC represents complex behavior due to electrochemical and mechanical interaction. Damage models are proposed to predict crack initiation time for stainless steel under constant load using the concept of continuum damage mechanics to show incremental damage accumulation which finally leads to failure of the material. Two damage models applicable to prediction of damage in SCC, Lemaitre damage model and damage driving force model proposed by Kamaya are compared. The comparative study of the results obtained by these damage models shows that in Lemaitre damage law cracks initiate randomly while in damage driving force model the stress concentration occurs around the periphery of damaged element results in increased damage force. The study can be used to estimate the crack initiation time in SCC under corrosive atmosphere.

scholarly journals Experimental and Numerical Impact Analysis of Automotive Bumper Brackets Made of 2D Triaxially Braided CFRP Composites

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3554
Author(s):  
Robert Böhm ◽  
Andreas Hornig ◽  
Tony Weber ◽  
Bernd Grüber ◽  
Maik Gude
Keyword(s):  
High Speed ◽  
Impact Analysis ◽  
Damage Model ◽  
Drop Tower ◽  
Structural Deformation ◽  
Impact Behavior ◽  
Speed Test ◽  
Damage Models ◽  
The Impact ◽  
Carbon Fiber Epoxy

The impact behavior of carbon fiber epoxy bumper brackets reinforced with 2D biaxial and 2D triaxial braids was experimentally and numerically analyzed. For this purpose, a phenomenological damage model was modified and implemented as a user material in ABAQUS. It was hypothesized that all input parameters could be determined from a suitable high-speed test program. Therefore, novel impact test device was designed, developed and integrated into a drop tower. Drop tower tests with different impactor masses and impact velocities at different bumper bracket configurations were conducted to compare the numerically predicted deformation and damage behavior with experimental evidence. Good correlations between simulations and tests were found, both for the global structural deformation, including fracture, and local damage entities in the impact zone. It was proven that the developed phenomenological damage models can be fully applied for present-day industrial problems.

Comparison of Interfacial and Continuum Models for Dynamic Fragmentation Analysis

2018 ◽  
Author(s):  
Bahador Bahmani ◽  
Philip Clarke ◽  
Reza Abedi
Keyword(s):  
Damage Model ◽  
Compressive Load ◽  
Stochastic Field ◽  
Damage Models ◽  
Coupled Equations ◽  
Rate Dependent ◽  
Fracture Simulation ◽  
Microstructure Effects ◽  
Dynamic Brittle Fracture ◽  
Final System

The microstructural design has an essential effect on the fracture response of brittle materials. We present a stochastic bulk damage formulation to model dynamic brittle fracture. This model is compared with a similar interfacial model for homogeneous and heterogeneous materials. The damage models are rate-dependent, and the corresponding damage evolution includes delay effects. The delay effect provides mesh objectivity with much less computational efforts. A stochastic field is defined for material cohesion and fracture strength to involve microstructure effects in the proposed formulations. The statistical fields are constructed through the Karhunen-Loeve (KL) method. An advanced asynchronous Spacetime Discontinuous Galerkin (aSDG) method is used to discretize the final system of coupled equations. Application of the presented formulation is shown through dynamic fracture simulation of rock under a uniaxial compressive load. The final results show that a stochastic bulk damage model produces more realistic results in comparison with a homogenizes model.

Sign in / Sign up

Export Citation Format

Share Document