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Chengxiang Yang - One of the best experts on this subject based on the ideXlab platform.

  • a novel application of Strain Energy for fracturing process analysis of hard rock under true triaxial compression
    Rock Mechanics and Rock Engineering, 2019
    Co-Authors: Yan Zhang, Xiating Feng, Xiwei Zhang, Zhaofeng Wang, Mostafa Sharifzadeh, Chengxiang Yang
    Abstract:

    Energy principles, which can favorably explain the complete rock failure process, are one of the most reliable analysis approaches in rock mechanics and engineering. In this study, a Strain Energy approach under true triaxial compression (TTC) is proposed. On this basis, the Energy evolution characteristics and variations of different failure behavior types (Class I, Class II and ductile failure) under TTC are analyzed. The variations of the Strain Energy characteristics of Beishan granite with σ2 and σ3 under TTC are studied. The results indicate that the total Strain Energy U and the elastic Strain Energy $$U^{e}$$ of Beishan granite increase with the increasing σ2 or σ3. The dissipated Strain Energy $$U^{d}$$ rapidly increases when the value of e1/e1peak is approximately 0.6–0.8. The influence of σ3 on the rock failure mode and Energy evolution characteristics is greater than that of σ2. In highly brittle rocks, the tensile cracking of the rock microstructure is dominant, and the rock has a high Strain Energy storage capacity and a low Strain Energy dissipation capacity. The cumulative acoustic emission (AE) count rate curve shows the same trend as the total dissipated Strain Energy $$U^{d}$$ curve. The research results show that the proposed Strain Energy analysis method for TTC can explain the macroscopic failure behaviors, microscopic failure mechanism and AE characteristics of Beishan granite under TTC, thereby providing new ideas and methods for investigating the behaviors of deep underground hard rock.

  • Strain Energy evolution characteristics and mechanisms of hard rocks under true triaxial compression
    Engineering Geology, 2019
    Co-Authors: Yan Zhang, Xiating Feng, Chengxiang Yang, Xiwei Zhang, Zhaofeng Wang, Mostafa Sharifzadeh, Rui Kong, Jun Zhao
    Abstract:

    Abstract The Energy evolution processes and mechanisms between three hard rocks are studied using a Strain Energy analysis method under true triaxial compression (TTC). Using Beishan granite as an example, the change in the Energy storage limit Umaxe, Strain Energy ratio and Strain Energy conversion rate for different σ2 and σ3 values is investigated. The research results indicate that within the scope of this study, the Energy evolution processes and characteristics are largely similar at pre-peak, and notably different at post-peak. The Energy storage limit Umaxe of the Beishan granite indicates an approximately slow increase with an increasing σ2, whereas its mean value shows a favorably linear increase with an increasing σ3. The elastic Strain Energy ratio shows a reverse relationship with that of the dissipated Strain Energy during rock failure. For an increasing σ2, the conversion rates of the total elastic Strain Energy Ue and the total dissipated Strain Energy Ud of the Beishan granite demonstrate a poor relationship at both pre- and post-peak. For an increasing σ3, the mean values indicate a favorable linear change at both pre- and post-peak. The total Strain Energy and total elastic Energy of the different hard rocks increase with increasing σ2 or σ3 values at pre-peak, whereas the total dissipated Strain Energy increases with an increasing σ3 and decreases with an increasing σ2 at pre-peak. When the external conditions are not considered, the difference in the elastic and plastic deformation capacities, which influence the Energy difference in different rocks, is influenced by the mineral compositions and microstructures of the different rocks.

Shun-peng Zhu - One of the best experts on this subject based on the ideXlab platform.

  • Strain Energy based multiaxial fatigue life prediction under normal shear stress interaction
    International Journal of Damage Mechanics, 2019
    Co-Authors: Shun-peng Zhu, Qiang Liu, Ayhan Ince
    Abstract:

    Through characterizing the interaction of normal/shear stress–Strain behavior on material planes of TC4 alloys, a new Strain Energy critical plane model describing mean stress effects is proposed f...

  • Strain Energy gradient based lcf life prediction of turbine discs using critical distance concept
    International Journal of Fatigue, 2018
    Co-Authors: Yunhan Liu, Shun-peng Zhu, Qiang Liu
    Abstract:

    Abstract For aeroengine components with geometrical discontinuities like notches, low cycle fatigue (LCF) life prediction is critical for ensuring the engine structural integrity. In this regard, a concept of Strain Energy gradient is elaborated and a general procedure combining this concept with theory of critical distance is established for LCF life prediction of notch components, which relates its life with the Strain Energy distributed within the effective damage zone. For GH4169 and TC4 notched specimens as well as a case study of a high pressure turbine disc, the proposed procedure provides better life correlations than models of Fatemi-Socie and Smith-Watson-Topper.

  • a generalized frequency separation Strain Energy damage function model for low cycle fatigue creep life prediction
    Fatigue & Fracture of Engineering Materials & Structures, 2010
    Co-Authors: Shun-peng Zhu, H. Z. Huang
    Abstract:

    Fatigue-creep interaction is a key factor for the failures of many engineering components and structures under high temperature and cyclic loading. These fatigue-creep life prediction issues are significant in selection, design and safety assessments of those components. Based on the frequency-modified Manson-Coffin equation and Ostergren's model, a new model for high temperature low cycle fatigue (HTLCF), a generalized frequency separation-Strain Energy damage function model is developed. The approach used in this model to reflect the effects of time-dependent damaging mechanisms on HTLCF life is different from those used in all the earlier models. A new Strain Energy damage function is used to reduce the difference between the approximate Strain Energy and real Strain Energy absorbed during the damage process. This proposed model can describe the ef- fects of different time-dependent damaging mechanisms on HTLCF life more accurately than others. Comparing traditional frequency separation technique (FS) and Strain Energy frequency-modified approach (SEFS), the proposed model is widely applicable and more precise in predicting the life of fatigue-creep interaction. Experimental data from existing literature are used to demonstrate the feasibility and applicability of the proposed model. A good agreement is found between the predicted results and experimental data.

Yan Zhang - One of the best experts on this subject based on the ideXlab platform.

  • a novel application of Strain Energy for fracturing process analysis of hard rock under true triaxial compression
    Rock Mechanics and Rock Engineering, 2019
    Co-Authors: Yan Zhang, Xiating Feng, Xiwei Zhang, Zhaofeng Wang, Mostafa Sharifzadeh, Chengxiang Yang
    Abstract:

    Energy principles, which can favorably explain the complete rock failure process, are one of the most reliable analysis approaches in rock mechanics and engineering. In this study, a Strain Energy approach under true triaxial compression (TTC) is proposed. On this basis, the Energy evolution characteristics and variations of different failure behavior types (Class I, Class II and ductile failure) under TTC are analyzed. The variations of the Strain Energy characteristics of Beishan granite with σ2 and σ3 under TTC are studied. The results indicate that the total Strain Energy U and the elastic Strain Energy $$U^{e}$$ of Beishan granite increase with the increasing σ2 or σ3. The dissipated Strain Energy $$U^{d}$$ rapidly increases when the value of e1/e1peak is approximately 0.6–0.8. The influence of σ3 on the rock failure mode and Energy evolution characteristics is greater than that of σ2. In highly brittle rocks, the tensile cracking of the rock microstructure is dominant, and the rock has a high Strain Energy storage capacity and a low Strain Energy dissipation capacity. The cumulative acoustic emission (AE) count rate curve shows the same trend as the total dissipated Strain Energy $$U^{d}$$ curve. The research results show that the proposed Strain Energy analysis method for TTC can explain the macroscopic failure behaviors, microscopic failure mechanism and AE characteristics of Beishan granite under TTC, thereby providing new ideas and methods for investigating the behaviors of deep underground hard rock.

  • Strain Energy evolution characteristics and mechanisms of hard rocks under true triaxial compression
    Engineering Geology, 2019
    Co-Authors: Yan Zhang, Xiating Feng, Chengxiang Yang, Xiwei Zhang, Zhaofeng Wang, Mostafa Sharifzadeh, Rui Kong, Jun Zhao
    Abstract:

    Abstract The Energy evolution processes and mechanisms between three hard rocks are studied using a Strain Energy analysis method under true triaxial compression (TTC). Using Beishan granite as an example, the change in the Energy storage limit Umaxe, Strain Energy ratio and Strain Energy conversion rate for different σ2 and σ3 values is investigated. The research results indicate that within the scope of this study, the Energy evolution processes and characteristics are largely similar at pre-peak, and notably different at post-peak. The Energy storage limit Umaxe of the Beishan granite indicates an approximately slow increase with an increasing σ2, whereas its mean value shows a favorably linear increase with an increasing σ3. The elastic Strain Energy ratio shows a reverse relationship with that of the dissipated Strain Energy during rock failure. For an increasing σ2, the conversion rates of the total elastic Strain Energy Ue and the total dissipated Strain Energy Ud of the Beishan granite demonstrate a poor relationship at both pre- and post-peak. For an increasing σ3, the mean values indicate a favorable linear change at both pre- and post-peak. The total Strain Energy and total elastic Energy of the different hard rocks increase with increasing σ2 or σ3 values at pre-peak, whereas the total dissipated Strain Energy increases with an increasing σ3 and decreases with an increasing σ2 at pre-peak. When the external conditions are not considered, the difference in the elastic and plastic deformation capacities, which influence the Energy difference in different rocks, is influenced by the mineral compositions and microstructures of the different rocks.

A Zolghadr - One of the best experts on this subject based on the ideXlab platform.

  • cyclical parthenogenesis algorithm for guided modal Strain Energy based structural damage detection
    Applied Soft Computing, 2017
    Co-Authors: A Kaveh, A Zolghadr
    Abstract:

    Abstract In this paper, a newly developed multi-agent meta-heuristic method, named Cyclical Parthenogenesis Algorithm (CPA), is incorporated into a guided modal Strain Energy based structural damage detection technique. A modal Strain Energy based index is used to guide the structural damage identification process, which is formulated as an inverse optimization problem. Generalized Flexibility Matrix (GFM) of the structure is used to define the objective function of the optimization problem. Three numerical examples are provided in order to examine the viability of the proposed method. The results indicate that the proposed method is capable of locating and quantifying structural damage using only the first few modes of the structure. The results are also compared with those of three other meta-heuristic algorithms in order to show the efficiency of CPA in solving the problem.

Liaojun Yao - One of the best experts on this subject based on the ideXlab platform.

  • discussion on the use of the Strain Energy release rate for fatigue delamination characterization
    Composites Part A-applied Science and Manufacturing, 2014
    Co-Authors: Liaojun Yao, R C Alderliesten, Meiying Zhao, Rinze Benedictus
    Abstract:

    Abstract This paper discusses the use of the Strain Energy release rate (SERR) as a parameter to characterize fatigue delamination growth in composite materials. Based on the observed difference in fatigue delamination response, it is argued that the fibre bridging generated during quasi-static and fatigue loading is significantly different and normalization of fatigue data with quasi-static SERR becomes meaningless. From the physical view, bridging fibres should not impose any Strain Energy release during fatigue delamination, unless they fail. This is supported by analyzing the earlier mentioned experiments with an Energy approach. When the measured Strain Energy release normalized against the applied number of cycles is plotted against the fatigue delamination growth rate, all data approximately coincides to a single curve. It is therefore concluded that the current use of SERR to characterize fatigue delamination growth is not in agreement with the physical concept of Strain Energy release.