Five-phase sphere equivalent model of recycled concrete and numerical simulation based on the base force element method

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yijiang Peng ◽  
Zhenghao Wu ◽  
Liping Ying ◽  
Desi Yang
Keyword(s):  
Numerical Simulation ◽  
Transition Zone ◽  
Interfacial Layer ◽  
Interfacial Transition Zone ◽  
Recycled Concrete ◽  
Equivalent Model ◽  
Content Type ◽  
Proposed Model ◽  
Force Element ◽  
Element Method

Purpose This paper aims to propose the five-phase sphere equivalent model of recycled concrete, which can be used to deduce the theoretical formulas for the Poisson’s ratio and effective elastic modulus. Design/methodology/approach At a mesoscopic level, the equivalent model converts the interfacial layer, which consists of the new interfacial transition zone (ITZ), the old mortar and the old (ITZ), into a uniform equivalent medium. This paper deduces a strength expression for the interfacial transition zone at the microscopic level using the equivalent model and elastic theory. In addition, a new finite element method called the base force element method was used in this research. Findings Through numerical simulation, it was found that the mechanical property results from the five-phase sphere equivalent model were in good agreement with those of the random aggregate model. Furthermore, the proposed model agree on quite well with the available experimental data. Originality/value The equivalent model can eliminate the influence of the interfacial layer on the macroscopic mechanical properties, thereby improving the calculation accuracy and computational efficiency. The proposed model can also provide a suitable model for multi-scale calculations.

Research on softening curve of recycled concrete using base force element method in meso-level

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yijiang Peng ◽  
Xiyun Chen ◽  
Liping Ying ◽  
Mahmoud M.A. Kamel
Keyword(s):  
Uniaxial Tension ◽  
Transition Zone ◽  
Level Structure ◽  
Interfacial Transition Zone ◽  
Recycled Concrete ◽  
Content Type ◽  
Meso Level ◽  
Softening Curve ◽  
Force Element ◽  
Element Method

Purpose Based on the base force element method, a two-dimensional random circle aggregate model with Monte Carlo principle is proposed to carry out research on softening curve in meso-level. Design/methodology/approach The meso-level structure of recycled concrete is considered as the five-phase materials composed of aggregate, old interfacial transition zone, old mortar, new interfacial transition zone and new mortar. A multi-polyline damage model is adopted to describe the nonlinear mechanical behavior of recycled concrete material. The destruction state of the element is determined by the first strength theory. The research studies on damage process of recycled concrete under the loading conditions of uniaxial tension were established using the base force element method. Findings The softening curves of recycled concrete are obtained, which are in good agreement with experiment results. Simulation results show that the macroscopic mechanical properties and failure mechanism can analyze more reasonably from mesoscopic structure. Besides that, it can be investigated from the numerical results of the size effect in recycled concrete through the mesoscopic heterogeneity. Furthermore, the form of aggregate distribution has influence on the crack path but little effect on the tensile strength of recycled concrete. Originality/value The results show that the base force element method has been successfully applied to the study of softening curve of recycled concrete under uniaxial tension.

Numerical Simulation of Uniaxial Compression Performance for Recycled Concrete Using Micromechanics

2012 ◽  
Vol 253-255 ◽  
pp. 550-554 ◽  
Author(s):  
Hua Ping Zhou ◽  
Yi Jiang Peng ◽  
Na Na Dang ◽  
Ji Wei Pu
Keyword(s):  
Numerical Simulation ◽  
Transition Zone ◽  
Uniaxial Compression ◽  
Cement Paste ◽  
Interfacial Transition Zone ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Hardened Cement ◽  
Hardened Cement Paste ◽  
Compression Performance

Recycled Aggregate Concrete (RAC) is referred to as Recycled Concrete (RC). In this paper, the compression performance of recycled concrete was researched using the micromechanics. The recycled concrete was taken as a five-phase composite material consisting of recycled coarse aggregate, old hardened cement paste, new hardened cement paste, the old interfacial transition zone (Old ITZ) and the new interfacial transition zone (New ITZ) on meso-level. A random aggregate model was used to simulate the meso-structure of recycled concrete. The propagation process of cracks and the mechanical properties of uniaxial compression specimens of recycled concrete were simulated using finite element method (FEM) with damage model. The numerical simulation results agree well with the corresponding experimental results. The results show that the specimen usually damaged along the old interfacial transition zone and the new interfacial transition zone.

Development of an aeroelastic model based on system identification using boundary elements method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rohollah Dehghani Firouz-Abadi ◽  
Mohammad Reza Borhan Panah
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Structural Models ◽  
Elastic Mode ◽  
Content Type ◽  
Reduced Order ◽  
Aerodynamic Model ◽  
Aeroelastic Model ◽  
Proposed Model ◽  
Element Method

Purpose The purpose of this paper is to analyze the stability of aeroelastic systems using a novel reduced order aeroelastic model. Design/methodology/approach The proposed aeroelastic model is a reduced-order model constructed based on the aerodynamic model identification using the generalized aerodynamic force response and the unsteady boundary element method in various excitation frequency values. Due to the low computational cost and acceptable accuracy of the boundary element method, this method is selected to determine the unsteady time response of the aerodynamic model. Regarding the structural model, the elastic mode shapes of the shell are used. Findings Three case studies are investigated by the proposed model. In the first place, a typical two-dimensional section is introduced as a means of verification by approximating the Theodorsen function. As the second test case, the flutter speed of Advisory Group for Aerospace Research and Development 445.6 wing with 45° sweep angle is determined and compared with the experimental test results in the literature. Finally, a complete aircraft is considered to demonstrate the capability of the proposed model in handling complex configurations. Originality/value The paper introduces an algorithm to construct an aeroelastic model applicable to any unsteady aerodynamic model including experimental models and modal structural models in the implicit and reduced order form. In other words, the main advantage of the proposed method, further to its simplicity and low computational effort, which can be used as a means of real-time aeroelastic simulation, is its ability to provide aerodynamic and structural models in implicit and reduced order forms.

Effects of Recycled Aggregate Replacement Rate on Compression Mechanical Behavior of Concrete Based on Base Force Element Method

2021 ◽  
Vol 894 ◽  
pp. 121-126
Author(s):  
Li Ping Ying ◽  
Yi Jiang Peng
Keyword(s):  
Failure Process ◽  
Strain Curve ◽  
Simple Algorithm ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Test Results ◽  
Force Element ◽  
Element Method

A meso-analysis method which is derived from the base force element method (BFEM) was proposed for recycled aggregate concrete (RAC). A simple algorithm was used to generate the convex recycled concrete aggregate (RCA) model. Uniaxial compression numerical simulations were carried out on the numerical specimens with different replacement rates of RCA. The model predictions were in a good agreement with the test results. The proposed method is very promising. It can totally predict the full stress-strain curve of RAC, as well as the failure process and failure mode, including strain softening and strain localization.

Numerical simulation of Plateau’s problem of minimal surfaces using nonvariational finite element method

2016 ◽  
Vol 33 (5) ◽  
pp. 1490-1507 ◽  
Author(s):  
Garima Mishra ◽  
Manoj Kumar
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Minimal Surfaces ◽  
Design Methodology ◽  
Engineering Application ◽  
Content Type ◽  
Plateau’S Problem ◽  
Plateau's Problem ◽  
Element Method

Purpose – Numerical solution of Plateau’s problem of minimal surface using non-variational finite element method. The paper aims to discuss this issue. Design/methodology/approach – An efficient algorithm is proposed for the computation of minimal surfaces and numerical results are presented. Findings – The solutions obtained here are examined for different cases of non-linearity and are found sufficiently accurate. Originality/value – The manuscript provide the non-variational solution for Plateau’s problem. Thus it has a good value in engineering application.

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