A constitutive model for the mechanical behaviour of bolted rock joint

2018 ◽  
pp. 179-183
Author(s):  
F. Pellet ◽  
M. Boulon
Keyword(s):  
Constitutive Model ◽  
Mechanical Behaviour ◽  
Rock Joint ◽  
Bolted Rock Joint

A Constitutive Model for Rock Joints under Cyclic Loading

2011 ◽  
Vol 243-249 ◽  
pp. 2211-2215
Author(s):  
Dong Mei Yang ◽  
Xiang Bo Qiu
Keyword(s):  
Constitutive Model ◽  
Mechanical Behaviour ◽  
Rock Joint ◽  
Joint Stiffness ◽  
Constitutive Models ◽  
Jointed Rock ◽  
Rock Joints ◽  
Cyclic Loads ◽  
Loaded Rock ◽  
Good Agreement

Cyclic loads are commonly encountered in geotechnical engineering; however most constitutive models do not account for the effect that such loads can have on the mechanical behaviour of soils and rocks. This work is concerned with the behaviour of jointed rock and, as the overall mechanical behaviour of jointed rock is usually dominated by the mechanical behaviour of the joints, it is focused on the behaviour of rock joints under cyclic loads. In particular, an extension of the existed constitutive model for cyclically loaded rock joints is presented. Variations of rock joint stiffness in both the normal and the shear directions of loading due to surface degradation are taken into account. The degradation of asperities of first and second order is considered, while a new relation is proposed for the joint stiffness in the normal direction during unloading. Numerical simulation results show good agreement of model predictions with existing experimental results.

scholarly journals A Novel Damage Model for Strata Layers and Coal Mass

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1928 ◽  
Author(s):  
Faham Tahmasebinia ◽  
Chengguo Zhang ◽  
Ismet Canbulat ◽  
Samad Sepasgozar ◽  
Serkan Saydam
Keyword(s):  
Constitutive Model ◽  
Strain Energy ◽  
Damage Model ◽  
Rock Joint ◽  
Coal Mass ◽  
Stored Energy ◽  
Rock Interaction ◽  
Geological Factors ◽  
Coal Rock ◽  
Joint Quality

Coal burst occurrences are affected by a range of mining and geological factors. Excessive slipping between the strata layers may release a considerable amount of strain energy, which can be destructive. A competent strata is also more vulnerable to riveting a large amount of strain energy. If the stored energy in the rigid roof reaches a certain level, it will be released suddenly which can create a serious dynamic reaction leading to coal burst incidents. In this paper, a new damage model based on the modified thermomechanical continuum constitutive model in coal mass and the contact layers between the rock and coal mass is proposed. The original continuum constitutive model was initially developed for the cemented granular materials. The application of the modified continuum constitutive model is the key aspect to understand the momentum energy between the coal–rock interactions. The transformed energy between the coal mass and different strata layers will be analytically demonstrated as a function of the rock/joint quality interaction conditions. The failure and post failure in the coal mass and coal–rock joint interaction will be classified by the coal mass crushing, coal–rock interaction damage and fragment reorganisation. The outcomes of this paper will help to forecast the possibility of the coal burst occurrence based on the interaction between the coal mass and the strata layers in a coal mine.

scholarly journals Energy-based constitutive modelling of local material properties of canine aortas

2016 ◽  
Vol 3 (9) ◽  
pp. 160365 ◽  
Author(s):  
Kaveh Laksari ◽  
Danial Shahmirzadi ◽  
Camilo J. Acosta ◽  
Elisa Konofagou
Keyword(s):  
Constitutive Model ◽  
Mechanical Behaviour ◽  
Computational Models ◽  
Constitutive Models ◽  
Constitutive Modelling ◽  
Axial Position ◽  
Aortic Tissue ◽  
Nonlinear Constitutive Model ◽  
Local Material Properties

This study aims at determining the in vitro anisotropic mechanical behaviour of canine aortic tissue. We specifically focused on spatial variations of these properties along the axis of the vessel. We performed uniaxial stretch tests on canine aortic samples in both circumferential and longitudinal directions, as well as histological examinations to derive the tissue's fibre orientations. We subsequently characterized a constitutive model that incorporates both phenomenological and structural elements to account for macroscopic and microstructural behaviour of the tissue. We showed the two fibre families were oriented at similar angles with respect to the aorta's axis. We also found significant changes in mechanical behaviour of the tissue as a function of axial position from proximal to distal direction: the fibres become more aligned with the aortic axis from 46° to 30°. Also, the linear shear modulus of media decreased as we moved distally along the aortic axis from 139 to 64 kPa. These changes derived from the parameters in the nonlinear constitutive model agreed well with the changes in tissue structure. In addition, we showed that isotropic contribution, carried by elastic lamellae, to the total stress induced in the tissue decreases at higher stretch ratios, whereas anisotropic stress, carried by collagen fibres, increases. The constitutive models can be readily used to design computational models of tissue deformation during physiological loading cycles. The findings of this study extend the understanding of local mechanical properties that could lead to region-specific diagnostics and treatment of arterial diseases.

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