scholarly journals Inverse Analysis of Concrete Meso-constitutive Model Parameters Considering Aggregate Size Effect

2020 ◽  
Vol 27 (1) ◽  
pp. 397-404
Author(s):  
Lixia Guo ◽  
Song Li ◽  
Ling Zhong ◽  
Lei Guo ◽  
Lunyan Wang
Keyword(s):  
Numerical Simulation ◽  
Genetic Algorithm ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Constitutive Model ◽  
Size Effect ◽  
Aggregate Size ◽  
Model Parameters ◽  
Random Aggregate ◽  
Mortar Matrix

AbstractThe meso numerical simulation has become an important method to study the characteristics of materials; however, the key to its further application is determining the parameters of meso-constitutive model. Considering that the meso-scale parameters of materials are hard to measure, this paper took into account the aggregate size effect and proposed a meso-parameter identification method by combining random aggregate numerical simulation and genetic algorithm. First, a random aggregate model of concrete was established, and its meso-model parameters were analyzed. The Morris method was used to analyze the sensitivity of meso-component parameters to the macro-responses, and results showed that the elastic modulus of mortar matrix, interface and large aggregates had a great effect on the peak strain and that the elastic modulus, Poisson’s ratio and tensile strength of interface and mortar matrix, as well as the Poisson’s ratio of large aggregates and the elastic modulus of small aggregates all had an effect on the peak stress, among which the interface tensile strength produced the greatest effect. Second, a parametric inversion and optimization function was established. The uniaxial compression numerical simulation test and genetic algorithm were combined to invert the meso-parameters, and results showed that compared with the single-aggregate parameter inversion curve, the multi-aggregate inversion stress-strain curve was much closer to the measured curve. That was because the aggregates of small size had lower elastic modulus, easing the stress concentration at the interface between aggregates and cement stone, and delaying the formation and growth of cracks.

scholarly journals Inverse analysis of concrete meso-constitutive model parameters considering aggregate size effect

2021 ◽  
Vol 28 (1) ◽  
pp. 314-314
Author(s):  
Lixia Guo ◽  
Song Li ◽  
Ling Zhong ◽  
Lei Guo ◽  
Lunyan Wang
Keyword(s):  
Constitutive Model ◽  
Size Effect ◽  
Inverse Analysis ◽  
Aggregate Size ◽  
Model Parameters

Numeric Analysis of Size Effect on Mesol Concrete Random Aggregate Model

2012 ◽  
Vol 226-228 ◽  
pp. 1780-1784
Author(s):  
Xin Yu Liang ◽  
Fa Ning Dang
Keyword(s):  
Size Effect ◽  
Random Number ◽  
Aggregate Size ◽  
Aggregate Model ◽  
Concrete Material ◽  
Strength Change ◽  
Random Aggregate ◽  
Random Aggregate Model ◽  
Random Location ◽  
Effect Ratio

In order to research that statics properties of concrete cylinder sample are influenced by micro-concrete material heterogeneity, by random aggregate models generated by different random number were established. By fixed aggregate size and constantly changing of the sample size, the concrete numerical model was simulated and Strength change of concrete samples was analyzed .So that strength influence of the aggregate location of the concrete random sample was study. Calculation shows that: the strength of concrete has been little effect by the aggregate random location, the size effect on concrete has been changed regularly, with the size effect ratio coefficient of aggregate and sample gradually increasing, the error square sum of strain was reduced and the brittlness of the samples becomes obvious.

The Concrete Fracture Performance Response to the Interface Transition Zone Parameters Based on Mesoscopic Simulation

2012 ◽  
Vol 170-173 ◽  
pp. 3482-3486 ◽  
Author(s):  
Min Du ◽  
Liu Jin ◽  
Xiu Li Du ◽  
Yan Zhao
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Fracture Energy ◽  
Transition Zone ◽  
Failure Process ◽  
Aggregate Model ◽  
Fracture Modes ◽  
Random Aggregate ◽  
Interface Transition Zone

The interface transition zone (ITZ) has a significant impact on the concrete’s mechanical properties and fracture modes. For the influence of ITZ’s strength and elastic modulus, the extended finite element method (XFEM) is adopted to simulate the mesostructure failure process by virtue of random aggregate model under uniaxial tension. The results show that ITZ’s strength and elastic modulus have a certain effect on the mechanical properties and fracture modes. With the tensile strength of ITZ increasing, the fractured modes transit from single coalescent crack to multiple non-coalescent cracks and the fracture energy increases, the ductility of concrete is enhanced. With the elastic modulus of ITZ increasing, the concrete’s elastic modulus increases, the tensile strength and the fracture energy decrease.

scholarly journals Determination of Holmquist–Johnson–Cook Constitutive Parameters of Coal: Laboratory Study and Numerical Simulation

Processes ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 386 ◽  
Author(s):  
Beijing Xie ◽  
Zheng Yan ◽  
Yujing Du ◽  
Zeming Zhao ◽  
Xiaoqian Zhang
Keyword(s):  
Numerical Simulation ◽  
Constitutive Model ◽  
Split Hopkinson Pressure Bar ◽  
Impact Damage ◽  
Triaxial Compression ◽  
Model Parameters ◽  
Compression Tests ◽  
Hopkinson Pressure Bar ◽  
The Impact ◽  
Constitutive Parameters

The main sensitivity parameters of the Holmquist–Johnson–Cook constitutive model for coal were obtained from a variety of tests such as uniaxial compression, uniaxial cyclic loading, splitting and triaxial compression tests, as well as the indirect derivation equation of a briquette. The mechanical properties of briquettes under dynamic impact were investigated using a split Hopkinson pressure bar experiment. Based on the experimental measurement of the Holmquist–Johnson–Cook constitutive model, the numerical simulation of briquette was performed using ANSYS/LS-DYNA software. A comparison between experimental and simulation results verified the correctness of simulation parameters. This research concluded that the failure of briquette at different impact velocities started from an axial crack in the middle of the coal body, and the sample was swollen to some extent. By the increase of impact velocity, the severity of damage in the coal body was increased, while the size of the coal block was decreased. Moreover, there was good compliance between experimental and simulated stress wave curves in terms of coal sample failure and fracture morphology at different speeds. Finally, the parameters of the validated Holmquist–Johnson–Cook constitutive model were applied to the numerical simulation model of the impact damage of heading face and the process of coal seam damage in the roadway was visually displayed. The obtained results showed that the Holmquist–Johnson–Cook constitutive model parameters suitable for the prominent coal body were of great significance for the improvement and exploration of the occurrence mechanism of coal and rock dynamic disasters.

Analysis and Comparison on Mechanical Properties between Full-Graded and Wet-Screened Concretes

2010 ◽  
Vol 168-170 ◽  
pp. 426-429 ◽  
Author(s):  
Shi Hua Zhou ◽  
Hua Quan Yang ◽  
Yun Dong
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Size Effect ◽  
Coarse Aggregate ◽  
Concrete Specimen ◽  
Hydraulic Engineering ◽  
Splitting Tensile Strength ◽  
Curing Condition

Based on typical hydraulic engineering, difference of performances between full-graded and wet-screened concrete was studied. Results showed that owing to the gradation effect and skeleton effect of coarse aggregate and the size effect of specimen, full-graded concrete was 105%, 75%, 65% and 115% in compressive strength, splitting tensile strength, ultimate tension and compressive elastic modulus respectively, compared with wet-screened concrete. Under the same curing condition, compressive strength of wet-screened standard concrete specimen can represent the actual compressive strength of full-graded concrete.

A Plastic Damage Model for Practical Application

2011 ◽  
Vol 255-260 ◽  
pp. 142-145 ◽  
Author(s):  
Hu Qi ◽  
Yun Gui Li ◽  
Xi Lin Lu
Keyword(s):  
Elastic Modulus ◽  
Constitutive Model ◽  
Efficient Method ◽  
Compression Strength ◽  
Damage Model ◽  
Model Parameters ◽  
Practical Application ◽  
Concrete Material ◽  
Plastic Damage ◽  
Tension Strength

In this paper, an efficient method is proposed to determine the value of the parameters for the Plastic Damage Model previously proposed by authors. With the proposed method the users can get the value of all the model parameters if only know the uniaxial tension strength, compression strength and elastic modulus of the concrete material. Finally, through several numerical simulations it is proved that the proposed method is effective and the constitutive model using the parameters which determined by the proposed method has the capability of simulating typical nonlinear performances of concrete material.

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