A new quasi-static delamination model with rate-dependence in interface damage and its operation under cyclic loading

2021 ◽  
Author(s):  
Roman Vodička
Keyword(s):  
Cyclic Loading ◽  
Rate Dependence ◽  
Interface Damage

scholarly journals Structural Health Monitoring and Interface Damage Detection for Infill Reinforced Concrete Walls in Seismic Retrofit of Reinforced Concrete Frames Using Piezoceramic-Based Transducers Under the Cyclic Loading

2019 ◽  
Vol 9 (2) ◽  
pp. 312 ◽  
Author(s):  
Wen-I Liao ◽  
Fu-Pei Hsiao ◽  
Chien-Kuo Chiu ◽  
Chin-En Ho
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
The Other ◽  
Structural Members ◽  
Interface Failure ◽  
Loading Test ◽  
Structural Health ◽  
Interface Damage

In this work, the piezoceramic-based transducers are used to perform the structural health monitoring (SHM) and interface damage detecting of non-ductile reinforced concrete (RC) frames retrofitted by post-installed RC walls. In order to develop the post-embedded piezoceramic-based transducers that can be used to identify interface failure or cracks between two structural members in retrofit construction, this work adopts the cyclic loading to test two specimens with post-embedded piezoceramic-based transducers (PPT). Since the failure of an interface between the post-installed wall and beam occurs, one of the specimens has damage in the foundation and existing boundary column and the other has damage in the top ends of column and wall. During the cyclic loading test, one transducer was used as an actuator to generate the stress waves and the other transducers were used as the sensors to detect the waves. In damaged specimens, the existence and locations of cracks and the interface damage can be detected by analyzing the wave response. Moreover, the severity of damage to the specimens can also be estimated. The experimental results indicate the effectiveness of the piezoceramic-based approach in the SHM and locating damage in shear-critical RC structural members under the seismic loading.

An Influence of Cyclic Loading on Behaviour of a Hysteretic Interface Damage Model

2019 ◽  
Vol 827 ◽  
pp. 275-281
Author(s):  
Roman Vodička
Keyword(s):  
Cyclic Loading ◽  
Cyclic Load ◽  
Endurance Limit ◽  
Damage Model ◽  
Interface Layer ◽  
Actual State ◽  
Cyclic Loads ◽  
Inertial Effects ◽  
Damage Propagation ◽  
Interface Damage

A computational interface damage model which takes into account crack initiation andgrowth along connections between parts of a multi-domain structure is proposed and is exposed tosituations where cyclic loading and its effects on the structure are noticeable, though the inertial effects are not considered. Modelling of damage takes into account various aspects of damage propagation and invoking of an interface crack. First, the degradation function of the interface layer controls the stressseparation relation on damage evolution. Second, the instant of triggering and cessation of damage propagation may in situations of cyclic loads depend on the actual state of the structure, influencing thus its endurance limit. Finally, the hysteretic character of damage provides together with loadingunloading conditions a fatigue-like character, where the crack appears for smaller magnitude of the cyclic load than for pure uploading. The numerical solution and a short parametric study is provided for a simplified situation of single damageable interface spring.

A Quasi-Static Delamination Model with Rate-Dependent Interface Damage Exposed to Cyclic Loading

2018 ◽  
Vol 774 ◽  
pp. 84-89 ◽  
Author(s):  
Roman Vodička ◽  
Katarína Krajníková
Keyword(s):  
Numerical Analysis ◽  
Cyclic Loading ◽  
Cohesive Zone ◽  
Cyclic Load ◽  
Cohesive Zone Model ◽  
Zone Model ◽  
Interface Damage ◽  
Domain Structures ◽  
Rate Dependent ◽  
Damage Process

A model for numerical analysis of interface damage which leads to interface crack initiationand propagation in multi-domain structures under cyclic loading is considered. Modelling of damagetakes into account various relations between interface stresses and displacement gaps providing theresponse of a cohesive zone model, additionally equipped by a kind of viscosity associated to theevolution of the interface damage. Together with repeating loading-unloading conditions, it makesthis damage process to have a fatigue-like character, where the crack appears for smaller magnitudeof the cyclic load than for pure uploading.

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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