scholarly journals Study on Damage Evolution Model of Sandstone under Triaxial Loading and Postpeak Unloading Considering Nonlinear Behaviors

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Tianbai Zhou ◽  
Yueping Qin ◽  
Jian Cheng ◽  
Xiaoyu Zhang ◽  
Qiufeng Ma
Keyword(s):  
Damage Evolution ◽  
Energy Balance Equation ◽  
Stress Strain ◽  
Triaxial Loading ◽  
Nonlinear Properties ◽  
Confining Pressures ◽  
Strain Relationship ◽  
Loading And Unloading ◽  
Nonlinear Behaviors ◽  
Initial Compaction

Conventional triaxial loading and unloading tests were carried out on sandstone samples in the Zigong area, of Sichuan Province, China. The changes in the elastic modulus of the unloading curves under different confining pressures were calculated, and the evolution law of the nonlinear properties of rock was analyzed. The results show that the rock is subjected to nonlinear damage during initial compaction, the elastic phase, destruction, and postpeak unloading. Moreover, the nonlinear behaviors of rock are restrained by the confining pressures. On this basis, a nonlinear stress-strain relationship affected by the average stress is proposed to describe nonlinear behaviors in the initial compaction stage. According to the test data, the evolution laws of various energies inside the rock during loading and unloading cycles are obtained. The results show that the external work is transformed into elastic energy and damage dissipated energy. Based on the energy analysis, the energy balance equation is established according to the law of energy conservation. By deriving the energy balance equation, the damage evolution equation of sandstone under triaxial loading is solved to establish a continuous constitutive model. The calculation results of the model are compared with the test results from two aspects of loading and postpeak unloading. The comparison results show that the proposed model, which reflects the whole stress-strain process and nonlinear properties of rock, could also describe the stress-strain relationship at the postpeak unloading stage to some extent.

scholarly journals Stress-Strain Relationship of Steel Fiber Reinforced Alkali Activated Slag Concrete under Static Compression

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xiaohui Yuan ◽  
Huiting Guan ◽  
Yanyu Shi
Keyword(s):  
Damage Evolution ◽  
Steel Fiber ◽  
Strain Curve ◽  
Fiber Reinforced ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Alkali Activated Slag ◽  
Strain Relationship ◽  
Activated Slag ◽  
Alkali Activated

Stress-strain curve can accurately reflect the mechanical behavior of materials, and it is very important for structural design and nonlinear numerical analysis. Some cube and prism specimens were made to investigate the physical and mechanical properties of steel fiber reinforced alkali activated slag concrete (AASC); test results show that the strength, Young’s Elastic Modulus, and Poisson’s ratio all increase with the increase of steel fiber content. The steel fiber reinforced AASC shows an excellent postcracking behavior. Damage evolution parameter (D) was used to describe the formation and propagation of cracks, and continuum damage evolution model of steel fiber reinforced AASC was established by Weibull and Cauchy distribution. The establishing model can well describe the geometric characteristics of the key points of the concrete materials stress-strain curve. Finally, the accuracy of the model was verified by comparing the test stress-strain relationship curve of steel fiber reinforced AASC.

Microcrack Evolution and Stress-Strain Relationship of Saturated Concrete

2011 ◽  
Vol 243-249 ◽  
pp. 4462-4465
Author(s):  
Dan Zheng ◽  
Xin Xin Li
Keyword(s):  
Damage Evolution ◽  
Damage Mechanics ◽  
Concrete Strength ◽  
Energy Reduction ◽  
External Loading ◽  
Stress Strain ◽  
Strain Relationship ◽  
Saturated Concrete ◽  
Relationship Of ◽  
Cement Surface

The strength and stress-strain relationship of saturate concrete is investigated in this paper. The influence of moisture to concrete strength is assumed to be related to cement surface energy reduction by water. The initial elastic modulus of concrete is obtained by considering the deformation of both pore and microcracks in concrete. The stress-strain relationship is achieved with damage mechanics by comparing the damage evolution rules between dry and saturated concrete under external loading. The comparison between experiments and the results by the model proposed in this paper indicates a favorable agreement.

In Situ Characterization of Soils for Prediction of Stress-Strain Relationship

1983 ◽  
Author(s):  
K. Arulanandan ◽  
Y. Dafalias ◽  
L. R. Herrmann ◽  
A. Anandarajah ◽  
N. Meegoda
Keyword(s):  
In Situ Characterization ◽  
Stress Strain ◽  
Strain Relationship

scholarly journals Residual stress-strain relationship for the biochar-based mortar after exposure to elevated temperature

2021 ◽  
pp. e00540
Author(s):  
Satheeskumar Navaratnam ◽  
Hendrik Wijaya ◽  
Pathmanathan Rajeev ◽  
Priyan Mendis ◽  
Kate Nguyen
Keyword(s):  
Residual Stress ◽  
Elevated Temperature ◽  
Stress Strain ◽  
Strain Relationship

scholarly journals Stress–strain relationship model of glulam bamboo under axial loading

2020 ◽  
Vol 29 ◽  
pp. 2633366X2095872
Author(s):  
Yang Wei ◽  
Mengqian Zhou ◽  
Kunpeng Zhao ◽  
Kang Zhao ◽  
Guofen Li
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Failure Modes ◽  
Axial Loading ◽  
Tensile Failure ◽  
Stress Strain ◽  
Laminated Bamboo ◽  
Bamboo Scrimber ◽  
Strain Relationship ◽  
Strain Model

Glulam bamboo has been preliminarily explored for use as a structural building material, and its stress–strain model under axial loading has a fundamental role in the analysis of bamboo components. To study the tension and compression behaviour of glulam bamboo, the bamboo scrimber and laminated bamboo as two kinds of typical glulam bamboo materials were tested under axial loading. Their mechanical behaviour and failure modes were investigated. The results showed that the bamboo scrimber and laminated bamboo have similar failure modes. For tensile failure, bamboo fibres were ruptured with sawtooth failure surfaces shown as brittle failure; for compression failure, the two modes of compression are buckling and compression shear failure. The stress–strain relationship curves of the bamboo scrimber and laminated bamboo are also similar. The tensile stress–strain curves showed a linear relationship, and the compressive stress–strain curves can be divided into three stages: elastic, elastoplastic and post-yield. Based on the test results, the stress–strain model was proposed for glulam bamboo, in which a linear equation was used to describe the tensile stress–strain relationship and the Richard–Abbott model was employed to model the compressive stress–strain relationship. A comparison with the experimental results shows that the predicted results are in good agreement with the experimental curves.

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