Analysis of Masonry Structures Subject to Variable Loads: A Numerical Approach Based on Damage Mechanics

Author(s):  
A. Callerio ◽  
E. Papa ◽  
A. Nappi
2015 ◽  
Vol 784 ◽  
pp. 500-507 ◽  
Author(s):  
Hiroki Tamai ◽  
Yoshimi Sonoda

In the civil and structural engineering field, there are so many problems regarding act of impact loading against some structures due to natural disaster. So it is important to evaluate the damage condition of them after impact loading, and to estimate the residual performance of them. This study is focused on a reinforced concrete (herein after called RC) structure such as caisson breakwater and rock-shed. In order to quantitatively evaluate the dynamic behavior and cumulative damage of RC members under low-velocity single and repeated impact loading, we conducted numerical approach by using the theory of Continuum Damage Mechanics (herein after called CDM). At the result, we clarified not only impact behavior of the members but also the relationship between cumulative kinetic energy of repeated impact loading and cumulative damage of the members. In addition, applicability limit of our model based on scalar damage modeling was clarified.


2018 ◽  
Vol 11 (1) ◽  
pp. 26-51 ◽  
Author(s):  
G. P. PELLIZZER ◽  
E. D. LEONEL ◽  
C. G. NOGUEIRA

Abstract Every structure is subjected to the effects of time and environment on which they are located. The consideration of these effects and their consequences in design phase is called nowadays as durability analysis of the structural system. The corrosion of the reinforcement steel through the chloride penetration inside the concrete is the main cause of the lifetime deterioration of the reinforced concrete structures. As a direct consequence, the corrosion affects the resistant capacity of the structural elements as the process evolves over time. Therefore, the appropriate prediction of the structural lifetime depends directly of the prevision capacity of those effects over the behavior of the structural systems. In this work, a mechanical model that combines the corrosion effects over the reinforcement and the concrete and steel material nonlinear responses is proposed to predict the resistant loss of reinforced concrete beams over the time. The steel and concrete nonlinear behavior was modeled by model based on unidimensional plasticity theory and damage mechanics, respectively. The Fick’s laws and empirical methods based on the Faraday’s laws were used to represent chloride penetration inside concrete and reinforced degradation, respectively. A simplified process was adopted to simulate the corrosion beginning in different times over the structure. The results showed that the rate of loss resistant capacity of the analyzed beam is higher in the first years after the beginning of corrosion and tend to stabilized in subsequent years. Furthermore, the structural behavior is very sensitive regarding the considered corrosive effects in the analyses.


2012 ◽  
Vol 22 (2) ◽  
pp. 188-218 ◽  
Author(s):  
J Lian ◽  
M Sharaf ◽  
F Archie ◽  
S Münstermann

The ductile damage mechanisms dominating in modern high-strength steels have emphasised the significance of the onset of damage and the subsequent damage evolution in sheet metal forming processes. This paper contributes to the modelling of the plasticity and ductile damage behaviour of a dual-phase steel sheet by proposing a new damage mechanics approach derived from the combination of different types of damage models. It addresses the influence of stress state on the plasticity behaviour and onset of damage of materials, and quantifies the microstructure degradation using a dissipation-energy-based damage evolution law. The model is implemented into ABAQUS/Explicit by means of a user material subroutine (VUMAT) and applied to the subsequent numerical simulations. A hybrid experimental and numerical approach is employed to calibrate the material parameters, and the detailed program is demonstrated. The calibrated parameters and the model are then verified by experiments at different levels, and a good agreement between the experimental and numerical results is achieved.


Author(s):  
Calvin M. Stewart ◽  
Ali P. Gordon

The purpose of this study is to develop a numerical approach to simulate the creep cracking of a Ni-base superalloy. The approach is based in continuum damage mechanics (CDM) and uses the classic Kachanov-Rabotnov constitutive equations for creep deformation and damage evolution. Creep damage takes the form of defects such as microcracks, cavities, voids, etc. A numerical crack growth algorithm is developed to predict the onset of crack initiation and the successive growth of cracks via element death in the general purpose finite element software ANSYS. In this paper, the Kachanov-Rabotnov constitutive model is implemented as a user material model in ANSYS and the numerical crack growth algorithm is developed and written in ANSYS parametric design language (APDL) command code. A study of mesh size in relation to initial flaw size and initiation time is performed. A demonstration of the proposed numerical crack growth algorithm is performed and a qualitative analysis conducted. A series of improvements and parametric studies are suggested for future work.


2016 ◽  
Vol 113 ◽  
pp. 752-763 ◽  
Author(s):  
Cemil Akcay ◽  
Tarik Serhat Bozkurt ◽  
Baris Sayin ◽  
Baris Yildizlar

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