scholarly journals A numerical and experimental study on the tensile behavior of plasma shocked granite under dynamic loading

2017 ◽  
Vol 50 (2) ◽  
pp. 41-62
Author(s):  
Ahmad Mardoukhi ◽  
Timo Saksala ◽  
Mikko Hokka ◽  
Veli-Tapani Kuokkala
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Mechanical Behavior ◽  
Thermal Shock ◽  
Dynamic Loading ◽  
Split Hopkinson Pressure Bar ◽  
Tensile Behavior ◽  
Brazilian Disc ◽  
Brazilian Disc Test ◽  
Plasma Shock

This paper presents a numerical and experimental study on the mechanical behavior of plasma shocked rock. The dynamic tensile behavior of plasma shock treated Balmoral Red granite was studied under dynamic loading using the Brazilian disc test and the Split Hopkinson Pressure Bar device. Different heat shocks were produced on the Brazilian disc samples by moving the plasma gun over the sample at different speeds. Microscopy clearly showed that as the duration of the thermal shock increases, the number of the surface cracks and their complexity increases (quantified here as the fractal dimension of the crack patterns) and the area of the damaged surface grows larger as well. At the highest thermal shock duration of 0.80 seconds the tensile strength of the Brazilian disc sample drops by approximately 20%. In the numerical simulations of the dynamic Brazilian disc test, this decrease in tensile strength was reproduced by modeling the plasma shock induced damage using the embedded discontinuity finite element method. The damage caused by the plasma shock was modeled by two methods, namely by pre-embedded discontinuity populations with zero strength and by assuming that the rock strength is lowered and conform to the Weibull distribution. This paper presents a quantitative assessment of the effects of the heat shock, the surface microstructure and mechanical behavior of the studied rock, and a promising numerical model to account for the pre-existing crack distributions in a rock material.

Thermal shock effects on the mechanical behavior of granite exposed to dynamic loading

2020 ◽  
Vol 20 (3) ◽  
Author(s):  
Xiang Li ◽  
Baijin Li ◽  
Xibing Li ◽  
Tubing Yin ◽  
Yan Wang ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Thermal Shock ◽  
Dynamic Loading

scholarly journals Investigating mechanical properties of 3D printed parts manufactured in different orientations on Multijet printer

2021 ◽  
Author(s):  
Ramesh Chand ◽  
Vishal S Sharma ◽  
Trehan Rajeev
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Mechanical Behavior ◽  
Polymer Material ◽  
Polymeric Materials ◽  
Tensile Behavior ◽  
Jet Printing ◽  
3D Printed

Abstract Polymer material based products in the engineering field are most widely produced by the multi jet printing (MJP). These products impart inherent benefits in manufacturing intricate contours and shapes at less additional expenses. This emphasizes the importance of studying the mechanical behavior of the manufactured parts, using polymeric materials in different orientations. In this investigation density, tensile behavior & hardness were studied for 3D-printed parts produced in four different orientations (A, B, C and D). It is found that for the best mechanical properties part should be fabricated using orientation ‘A’. Furthermore, for density and tensile strength part should not be fabricated using orientation ‘C’. Also in case of hardness part should not be fabricated in orientation ‘B’.

Experimental Study of Flexural Tensile Strength of Sand Concrete Plates Reinforced with Metallic Fibers

2020 ◽  
Vol 857 ◽  
pp. 74-82
Author(s):  
Saloua Melais ◽  
Meriem Fakhreddine Bouali
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Mechanical Behavior ◽  
Flexural Tensile Strength ◽  
Concrete Plates ◽  
Metallic Fibers

This paper presents the findings of an experimental study of sand concrete plates reinforced with metallic fibers (BSFM) mixes with respect to a reference sandcrete without fibers (BST) that establishes a benchmark for the BSFM mixes. The performed tests are based on the characteristics of fresh sandcrete (density, slump) and on the mechanical behavior of slabs in centered flexion. It was concluded that the metallic fibers improves the tensile strength, rigidity and durability characteristic after cracking. These characteristics are at an optimum for a sand concrete reinforced with metal fibers (BSFM) with 30kg of fibers per m3 of sand concrete.

scholarly journals Energy Dissipation Characteristic of Red Sandstone in the Dynamic Brazilian Disc Test with SHPB Setup

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Fengqiang Gong ◽  
Jian Hu
Keyword(s):  
Energy Dissipation ◽  
Incident Energy ◽  
Split Hopkinson Pressure Bar ◽  
Critical Energy ◽  
Dissipated Energy ◽  
Brazilian Disc ◽  
Red Sandstone ◽  
Rock Materials ◽  
Brazilian Disc Test ◽  
Dissipation Characteristic

In order to quantitatively investigate the energy dissipation characteristic during the dynamic tension failure of rock materials, the dynamic Brazilian disc tests on red sandstone were conducted using the split Hopkinson pressure bar (SHPB) setup. The states of the specimens after different incident energies can be divided into three forms (i.e., the unruptured state, the ruptured state, and the broken state), and the failure processes of the specimens were recorded by using a high-speed camera. The results show that the ruptured state of the specimen corresponds to the critical failure strain. Taking the critical incident energy as a turning point, two positive linear fitting relations between the dissipated energy and incident energy before and after the point are obtained, and the dynamic linear dissipation law is found. When the incident energy is less than the critical energy, specimens were unruptured after impact. When the incident energy is greater than the critical energy, specimens will be broken after impact. According to the obtained linear energy dissipation law, the dynamic tensile energy dissipation coefficient (DTEDC) was introduced for quantitatively describing the dynamic energy dissipation capacity of rock materials in the dynamic Brazilian disc test. When the specimen is in the unruptured state, the ideal DTEDC is a constant value. When the specimen is in a broken state, the DTEDC increases with the increase of incident energy.

scholarly journals Numerical Analysis of Flattened Brazilian Disc Test Based on the Cusp Catastrophe Theory

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Min Wang ◽  
Ping Cao
Keyword(s):  
Tensile Strength ◽  
Catastrophe Theory ◽  
Poisson’S Ratio ◽  
Equivalent Stress ◽  
Poisson's Ratio ◽  
Fracture Plane ◽  
Cusp Catastrophe ◽  
Brazilian Disc ◽  
Brazilian Disc Test ◽  
Cusp Catastrophe Theory

The Brazilian disc test is a simple and useful technique to determine the tensile strength of rock materials. By using FLAC3D, 63 numerical simulations in total were performed when flattened Brazilian disc coefficient and Poisson’s ratio were different. Based on Griffith theory, the corresponding FISH language was compiled to record the Griffith equivalent stress. Through analysis of numerical simulation results, it is indicated that fracture plane was not the plane going through center of the Brazilian disc, which was in good agreement with the references. In addition, the flattened Brazilian disc coefficients had greater influence on tensile strength than Poisson’s ratio. Based on cusp catastrophe theory, the flattened Brazilian disc coefficient should not exceed 0.035 for the flattened Brazilian disc tests. Consequently, a tensile strength empirical formula considering flattened Brazilian disc coefficient by utilizing the flattened Brazilian disc test was established, which wasσt=0.9993 exp (-11.65ε)2p/πDt,ε≤0.035.

Textile-reinforced mortars; an experimental comparative study of tensile strength improvement methods

2022 ◽  
pp. 146442072110682
Author(s):  
Roohallah Ghasemi ◽  
Majid Safarabadi ◽  
Mojtaba Haghighi-Yazdi ◽  
Abolfazl Mirdehghan
Keyword(s):  
Experimental Study ◽  
Tensile Strength ◽  
Short Fiber ◽  
Tensile Behavior ◽  
Short Fibers ◽  
Method Performance ◽  
Interface Modification ◽  
Effective Factors ◽  
One Way Anova ◽  
Strength Improvement

In this article, an experimental study is conducted to compare eight improvement methods for the tensile strength of textile-reinforced mortars (TRM). 12 series of samples with different modification methods are compared to determine the most effective factors on crack initiation force and tensile strength of TRM. Eight modification methods are categorized under three main groups of mortar modification, fabric modification, and fabric-mortar interface modification. TRM's first crack force and ultimate force are considered as indices of method performance. One-way ANOVA and factorial analysis were also conducted to statically determine the most significant methods for improving TRM tensile behavior. The results showed that the modification of mortar by short fiber is the most effective method for the enhancement of TRM's first crack force. Also, the methods which led to the transfer of failure mode from mortar to fabrics were the most effective methods on TRM ultimate force improvement. The result showed that coating fabrics with epoxy affects TRM tensile strength more than all other methods. Extra enhancement of TRM ultimate force is achieved by adding silica fume to epoxy before coating the fabrics and spreading the sand and short fibers on impregnated fabrics.

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