A loading rate dependent cohesive model for concrete fracture

As an important parameter for concrete, fracture energy is difficult to accurately measure in high loading rate tests due to the limitations of experimental devices and methods. Therefore, the utilization of numerical methods to study the dynamic fracture energy of concrete is a simple and promising choice. This paper presents a numerical investigation on the influence of loading rate on concrete fracture energy and cracking behaviors. A novel rate-dependent cohesive model, which was programmed as a user subroutine in the commercial explicit finite element solver LS-DYNA, is first proposed. After conducting mesh sensitivity analysis, the proposed model is calibrated against representative experimental data. Then, the underlying mechanisms of the increase in fracture energy due to a high strain rate are determined. The results illustrate that the higher fracture energy during dynamic tension loading is caused by the wider region of the damage zone and the increase in real fracture energy. As the loading rate increases, the wider region of the damage zone plays a leading role in increasing fracture energy. In addition, as the strain rate increases, the number of microcracks whose fracture mode is mixed mode increases, which has an obvious effect on the change in real fracture energy.

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A viscous-cohesive model for concrete fracture in quasi-static loading rate

Engineering Fracture Mechanics ◽

10.1016/j.engfracmech.2020.106893 ◽

2020 ◽

Vol 228 ◽

pp. 106893

Author(s):

Fábio Luis Gea dos Santos ◽

José Luiz Antunes de Oliveira e Sousa

Keyword(s):

Static Loading ◽

Loading Rate ◽

Concrete Fracture ◽

Cohesive Model

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Experimental study on hardening characteristics and loading rate dependent mechanical behaviour of gypsum mixed sand

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.119992 ◽

2020 ◽

Vol 262 ◽

pp. 119992 ◽

Cited By ~ 1

Author(s):

Zain Maqsood ◽

Junichi Koseki ◽

Md. Kamrul Ahsan ◽

Masum Shaikh ◽

Hiroyuki Kyokawa

Keyword(s):

Experimental Study ◽

Mechanical Behaviour ◽

Loading Rate ◽

Rate Dependent

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Improved Nanoindentation Phase Transformation in Functional Structure of NiTi SMA and Graphene

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1119.160 ◽

2015 ◽

Vol 1119 ◽

pp. 160-164

Author(s):

Abbas Amini ◽

Chun Hui Yang ◽

Yang Xiang

Keyword(s):

Indentation Depth ◽

Loading Rate ◽

Spherical Indentation ◽

Niti Shape Memory Alloy ◽

Cooling Process ◽

Graphene Layers ◽

Loading Rates ◽

Rate Dependent ◽

Niti Sma ◽

Superelastic Deformation

Graphene layers were deposited on the surface of NiTi shape memory alloy (SMA) to enhance the spherical indentation depth and the phase transformed volume through an extra nanoscale cooling. The graphene-deposited NiTi SMA showed deeper nanoindentation depths during the solid-state phase transition, especially at the rate dependent loading zone. Larger superelastic deformation confirmed that the nanoscale latent heat transfer through the deposited graphene layers allowed larger phase transformed volume in the bulk and, therefore, more stress relaxation and depth can be achieved. During the indentation loading, the temperature of the phase transformed zone in the stressed bulk increased by ~12-43°C as the loading rate increased from 4,500 μN/s to 30,000 μN/s. The layers of graphene enhanced the cooling process at different loading rates by decreasing the temperature up to ~3-10°C depending on the loading rate.

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Nonlinear Rate-Dependent Stress-Strain Behavior of Light-Weight Textile Conveyor Belt

Materials Science Forum ◽

10.4028/www.scientific.net/msf.675-677.453 ◽

2011 ◽

Vol 675-677 ◽

pp. 453-456

Author(s):

Ze Xing Wang ◽

Jin Hua Jiang ◽

Nan Liang Chen

Keyword(s):

Loading Rate ◽

Testing Machine ◽

Rate Sensitivity ◽

Sensitivity Coefficient ◽

Conveyor Belt ◽

Uniaxial Tensile ◽

Stress Strain ◽

Strain Behavior ◽

Rate Dependent ◽

Dependent Behavior

In order to investigate the effect of loading rate on the tensile performance, the uniaxial tensile experiments were conducted on universal testing machine under different loading rates (5 mm/min, 10mm/min, 50 mm/min, 100 mm/min and 150 mm/min), and a constant gage length equal to 200mm, resulting in loading strain rate of 4.17×10-4, 8.33×10-4/s, 4.17×10-3/s, 8.33×10-3/s,1.25×10-2/s, and the tensile stress-strain curves were obtained. The experimental results show that the tensile properties of the conveyor belt exhibit obvious rate-dependent behavior. In this paper, the rate sensitivity coefficient varied with loading rate, was calculated, and the nonlinear rate-dependent behavior was also investigated.

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FEM Analysis on Tensile Force of Geosynthetic Reinforcement Arranged in GRS-RW Considering Variable Loading Rate

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.188.60 ◽

2012 ◽

Vol 188 ◽

pp. 60-65

Author(s):

Fu Lin Li ◽

Fang Le Peng

Keyword(s):

Finite Element ◽

Loading Rate ◽

Retaining Wall ◽

Tensile Force ◽

Fem Analysis ◽

Reinforced Soil ◽

Geosynthetic Reinforcement ◽

Geosynthetic Reinforced Soil ◽

Rate Dependent ◽

Dependent Behavior

The combined effects of the rate-dependent behavior of both the backfill soil and the geosynthetic reinforcement have been investigated, which should be attributed to the viscous property of material. A nonlinear finite element method (FEM) analysis procedure based on the Dynamic Relaxation method was developed for the geosynthetic-reinforced soil retaining wall (GRS-RW). In the numerical analysis, both the viscous properties of the backfill and the reinforcement were considered through the unified nonlinear three-component elastic-viscoplastic model. The FEM procedure was validated against a physical model test on geosynthetic-reinforced soil retaining wall with granular backfill. Extensive finite-element analyses were carried out to investigate the tensile force distributions in geosynthetic reinforcement of geosynthetic-reinforced soil retaining wall under the change of loading rate. It is found from the analyses that the presented FEM can well simulate the rate-dependent behavior of geosynthetic-reinforced soil retaining wall and the tensile force of geosynthetic reinforcement arranged in retaining wall.

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