Relationship between load/unload response ratio and damage variable and its application

Zhang, Langping; Yin, Xingyao; Liang, Ning

doi:10.1002/cpe.1513

Cited by 10 publications

(10 citation statements)

References 24 publications

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“…YIN et al, 1995WANG et al, 2004;YU et al, 2010YU et al, , 2011ZHANG et al, 2006aZHANG et al, , c, 2010. Prior to occurrence of a large earthquake, the LURR time series usually climb to an anomalously high value.…”

Section: Discussionmentioning

confidence: 99%

Failure Potential Evaluation in Engineering Experiments Using Load/Unload Response Ratio Method

Zhang

Yin

2011

Pure Appl. Geophys.

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Abstract-The Load/Unload Response Ratio (LURR) method is proposed for prediction of the failure of brittle heterogeneous materials. Application of the method typically involves evaluating the external load on materials or structures, differentiating between loading and unloading periods, determining the failure response during both periods from data input, and calculating the ratio between the two response rates. According to the method, the LURR time series usually climbs to an anomalously high peak prior to the macro-fracture. To show the validity of the approach in engineering practice, we applied it to the loading and unloading experimental data associated with a two-floor concrete-brick structure. Results show that the LURR time series of the two floors consists of the damage evolution of the structure: they are at low level for most of the time, and reach the maxima prior to the final fracture. We then attempt to combine the LURR values with damage variable (D) to provide the health assessment of the structure. The relationship between LURR and D, defined as a function of Weibull stochastic distribution, is set up to provide more detailed underlying physical means to study damage evolution of the structure. The fact that the damage evolution of the structure correlates well with the variation of LURR time series may suggest that the LURR approach can be severed as a useful tool to provide the health assessment to big scale structures or ancient buildings.

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Section: Discussionmentioning

confidence: 99%

Failure Potential Evaluation in Engineering Experiments Using Load/Unload Response Ratio Method

Zhang

Yin

2011

Pure Appl. Geophys.

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“…Tensile strain causes new damage when it increases. The damage becomes zero if the tensile strain decreases, which is called the unloading damage effect (Zhang et al, 2008) Under uniaxial loading/unloading, the LURR can be determined in two different ways:…”

Section: Lurr Calculation Based On Anisotropic Damagementioning

confidence: 99%

“…As the load acting on the rock increases, the defects propagate, or more damages are caused on the rock. Zhang et al (2008) studied the relationship between damage and loading/unloading at uniaxial loading conditions and derived an expression for calculating LURR. Under three dimensional loading conditions, the calculation of LURR is much more complicated and thus seismic energy or acoustic emission was adopted in the calculation of LURR by Yin et al (2007).…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Load-Unload Response Ratio (LURR) of Brittle Rocks

Zhu

Zhang

2014

Rock Mechanics and Its Applications in Civil, Mining, and Petroleum Engineering

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The load-unload response ratio (LURR) reflects damage evolution of rocks and thus is a good way for describing rock stability. With the background of stopping in a metal mine, this paper studies the relationship between LURR and damage of brittle rocks. Based on the elasto-brittle damage theory, the analytical expressions of LURR were first derived for brittle rocks under both uniaxial and conventional triaxial loading/unloading conditions. Then uniaxial and conventional triaxial loading/unloading tests were conducted on brittle rocks. The experimental results indicate that the LURR varies greatly at the initial stage possibly due to the compaction and heterogeneity of rock. As the load increases, the LURR keeps almost constant with occasional fluctuation possibly due to propagation of local cracks. When the rock is close to failure, the LURR presents abrupt increase or great fluctuation. The experimental results are in reasonable agreement with the derived analytical expressions of LURR.

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“…The relationship between LURR Y E and damage variable (D) based on the fact that the fracture limit of materials conforms to a Weibull distribution on a mesoscopic scale was established by Zhang et al [34].…”

Section: Damage Variable Of Coalmentioning

confidence: 99%

Seepage and Damage Evolution Characteristics of Gas-Bearing Coal under Different Cyclic Loading–Unloading Stress Paths

Zou

2018

Processes

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The mechanical properties and seepage characteristics of gas-bearing coal evolve with changes in the loading pattern, which could reveal the evolution of permeability in a protected coal seam and allow gas extraction engineering work to be designed by using the effect of mining multiple protective seams. Tests on gas seepage in raw coal under three paths (stepped-cyclic, stepped-increasing-cyclic, and crossed-cyclic loading and unloading) were carried out with a seepage tester under triaxial stress conditions. The permeability was subjected to the dual influence of stress and damage accumulation. After being subjected to stress unloading and loading, the permeability of coal samples gradually decreased and the permeability did not increase before the stress exceeded the yield stage of the coal samples. The mining-enhanced permeability of the coal samples in the loading stage showed a three-phase increase with the growth of stress and the number of cycles and exhibited an N-shaped increase under the stepped-cyclic loading while it linearly increased under the other two paths in the unloading stage. With the increase of peak stress and the accumulation of damage in coal samples, the sensitivity of the permeability of coal samples to stress gradually declined. The relationship between the damage variable and the number of cycles conformed to the Boltzmann function.

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Relationship between load/unload response ratio and damage variable and its application

Cited by 10 publications

References 24 publications

Failure Potential Evaluation in Engineering Experiments Using Load/Unload Response Ratio Method

Failure Potential Evaluation in Engineering Experiments Using Load/Unload Response Ratio Method

Experimental Study on Load-Unload Response Ratio (LURR) of Brittle Rocks

Seepage and Damage Evolution Characteristics of Gas-Bearing Coal under Different Cyclic Loading–Unloading Stress Paths

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