Finite element model for the long-term behaviour of composite steel-concrete push tests

2010 ◽  
Vol 10 (1) ◽  
pp. 45-67 ◽  
Author(s):  
O. Mirza ◽  
B. Uy
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Composite Steel

Comparison of femur strain under different loading scenarios: Experimental testing

2020 ◽  
Vol 235 (1) ◽  
pp. 17-27
Author(s):  
Ievgen Levadnyi ◽  
Jan Awrejcewicz ◽  
Yan Zhang ◽  
Yaodong Gu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Strain Distribution ◽  
Element Model ◽  
Surface Strain ◽  
Image Correlation ◽  
Loading Conditions ◽  
Bone Implant ◽  
Bone Stiffness

Bone fracture, formation and adaptation are related to mechanical strains in bone. Assessing bone stiffness and strain distribution under different loading conditions may help predict diseases and improve surgical results by determining the best conditions for long-term functioning of bone-implant systems. In this study, an experimentally wide range of loading conditions (56) was used to cover the directional range spanned by the hip joint force. Loads for different stance configurations were applied to composite femurs and assessed in a material testing machine. The experimental analysis provides a better understanding of the influence of the bone inclination angle in the frontal and sagittal planes on strain distribution and stiffness. The results show that the surface strain magnitude and stiffness vary significantly under different loading conditions. For the axial compression, maximal bending is observed at the mid-shaft, and bone stiffness is also maximal. The increased inclination leads to decreased stiffness and increased magnitude of maximum strain at the distal end of the femur. For comparative analysis of results, a three-dimensional, finite element model of the femur was used. To validate the finite element model, strain gauges and digital image correlation system were employed. During validation of the model, regression analysis indicated robust agreement between the measured and predicted strains, with high correlation coefficient and low root-mean-square error of the estimate. The results of stiffnesses obtained from multi-loading conditions experiments were qualitatively compared with results obtained from a finite element analysis of the validated model of femur with the same multi-loading conditions. When the obtained numerical results are qualitatively compared with experimental ones, similarities can be noted. The developed finite element model of femur may be used as a promising tool to estimate proximal femur strength and identify the best conditions for long-term functioning of the bone-implant system in future study.

Finite Element Model for Analysis of Time-Dependent Behaviour of Concrete-Filled Steel Tubular Arches

2014 ◽  
Vol 553 ◽  
pp. 606-611
Author(s):  
Kai Luo ◽  
Yong Lin Pi ◽  
Wei Gao ◽  
Mark A. Bradford
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Nonlinear Analysis ◽  
Element Model ◽  
Time Dependent ◽  
Concrete Core ◽  
Time Dependent Behaviour ◽  
Linear And Nonlinear ◽  
Dependent Behaviour

This paper presents a finite element model for the linear and nonlinear analysis of time-dependent behaviour of concrete-filled steel tubular (CFST) arches. It is known when a CFST arch is subjected to a sustained load, the visco-elastic effects of creep in the concrete core will result in significant increases of the deformations and internal forces in the long-term. In this paper, a finite element model is developed using the age-adjusted effective modulus method to describe the creep behaviour of the concrete core. The finite element results of long-term displacement and stress redistribution agree very well with their analytical counterparts. The finite element model is then used to compare the linear and nonlinear results for the long-term behaviour of shallow CFST arches. It is demonstrated that the linear analysis underestimates the long-term deformations and internal force significantly and that to predict the time-dependent behaviour shallow CFST arches accurately, the nonlinear analysis is essential.

scholarly journals Effect of Long-Term Soil Deformations on RC Structures Including Soil-Structure Interaction

2020 ◽  
Vol 6 (12) ◽  
pp. 2290-2311
Author(s):  
Kamel Bezih ◽  
Alaa Chateauneuf ◽  
Rafik Demagh
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Soil Structure ◽  
Element Model ◽  
Soil Structure Interaction ◽  
Structural Safety ◽  
Soil Behavior ◽  
Rc Structures ◽  
Structure Interaction

Lifetime service of Reinforced Concrete (RC) structures is of major interest. It depends on the action of the superstructure and the response of soil contact at the same time. Therefore, it is necessary to consider the soil-structure interaction in the safety analysis of the RC structures to ensure reliable and economical design. In this paper, a finite element model of soil-structure interaction is developed. This model addresses the effect of long-term soil deformations on the structural safety of RC structures. It is also applied to real RC structures where soil-structure interaction is considered in the function of time. The modeling of the mechanical analysis of the soil-structure system is implemented as a one-dimensional model of a spring element to simulate a real case of RC continuous beams. The finite element method is used in this model to address the nonlinear time behavior of the soil and to calculate the consolidation settlement at the support-sections and the bending moment of RC structures girders. Numerical simulation tests with different loading services were performed on three types of soft soils with several compressibility parameters. This is done for homogeneous and heterogeneous soils. The finite element model of soil-structure interaction provides a practical approach to show and to quantify; (1) the importance of the variability of the compressibility parameters, and (2) the heterogeneity soil behavior in the safety RC structures assessment. It also shows a significant impact of soil-structure interaction, especially with nonlinear soil behavior versus the time on the design rules of redundant RC structures. Doi: 10.28991/cej-2020-03091618 Full Text: PDF

scholarly journals Robust fibre optic sensor arrays for monitoring early-age performance of mass-produced concrete sleepers

2017 ◽  
Vol 17 (3) ◽  
pp. 635-653 ◽  
Author(s):  
Liam J Butler ◽  
Jinlong Xu ◽  
Ping He ◽  
Niamh Gibbons ◽  
Samir Dirar ◽  
...  
Keyword(s):  
Quality Control ◽  
Finite Element ◽  
Finite Element Model ◽  
Production Process ◽  
Sensor Arrays ◽  
Element Model ◽  
Bragg Grating ◽  
Early Age ◽  
Fibre Bragg Grating

This study investigates integrating fibre optic sensing technology into the production process of concrete railway sleepers. Robust fibre Bragg grating strain and temperature sensor arrays were developed specifically for this application and were designed for long-term monitoring of sleeper performance. The sensors were used to monitor sleeper production and to help gain a deeper understanding of their early-age behaviour which can highly influence long-term performance. In total, 12 sleepers were instrumented and strain data were collected during the entire manufacturing process including concrete casting and curing, prestressing strand detensioning and qualification testing. Following the production process, sleepers were stored temporarily and monitored for 4 months until being placed in service. The monitoring results highlight the intrinsic variability in strain development among identical sleepers, despite high levels of production quality control. Using prestress loss as a quality control indicator, the integrated sensing system demonstrated that sleepers were performing within Eurocode-based design limits prior to being placed in service. A three-dimensional nonlinear finite element model was developed to provide additional insight into the sleepers’ early-age behaviour. Based on the fibre Bragg grating–calibrated finite element model, more realistic estimates for the creep coefficient were provided and found to be 48% of the Eurocode-predicted values.

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