Journal of Theoretical and Applied Mechanics最新文献_第9页

Study of triaxial compression mechanical properties and pore-fracture characteristics of coal rocks in the Yili Basin, Xinjiang 新疆伊犁盆地煤岩三轴压缩力学特性及孔隙破裂特征研究

IF 0.7 4区工程技术

Journal of Theoretical and Applied Mechanics Pub Date : 2023-02-09 DOI: 10.15632/jtam-pl/159670

Cheng Shen, Ling Yue, Yang Liu

{"title":"Study of triaxial compression mechanical properties and pore-fracture characteristics of coal rocks in the Yili Basin, Xinjiang","authors":"Cheng Shen, Ling Yue, Yang Liu","doi":"10.15632/jtam-pl/159670","DOIUrl":"https://doi.org/10.15632/jtam-pl/159670","url":null,"abstract":"Compressive mechanical properties and pore-ﬁssure characteristics of coal rock specimens from three stably developed coal seams M 1 , M 8 and M 12 in the Xinjiang Yili Basin were investigated in detail by a series of tests. The results show that the compressive mechanical properties of coal rocks in the Yili Basin are signiﬁcantly aﬀected by the conﬁning pressure. The peak axial stress increases and the peak modulus of elasticity decreases as the conﬁning pressure increases. The peak axial strain increases and then remains constant, while the peak circumferential strain and peak volumetric strain increase and then decrease. The conﬁning pressure has almost no eﬀect on Poisson’s ratio of the coal rock specimens. In addition, electron microscopy tests show that the microscopic fraction of the coal rock specimens is predominantly vitrinite, accounting for 83.1%-89.2%, while the percentage of the inertinite group is relatively small, at 10.3%-16.1%. The throat radius of the coal rock is mainly concentrated around 1-2 µ m, while the pore radius of the coal rock is between 150-200 µ m. The coal rock has an overall ﬁne throat and low permeability, and the coal rock in the Yili Basin of Xinjiang is a typical low-permeability coal rock.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"31 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74343089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Research on optimal design of vibration reduction of centrifugal air conditioning chiller based on particle damping 基于颗粒阻尼的离心式空调冷水机组减振优化设计研究

IF 0.7 4区工程技术

Journal of Theoretical and Applied Mechanics Pub Date : 2023-01-18 DOI: 10.15632/jtam-pl/158842

Wangqiang Xiao, Jinsong Shi, Hui Chen, Hua Liu

引用次数: 1

Research on time-varying reliability of wind power gearbox with failure correlation 考虑故障相关性的风电齿轮箱时变可靠性研究

IF 0.7 4区工程技术

Journal of Theoretical and Applied Mechanics Pub Date : 2023-01-18 DOI: 10.15632/jtam-pl/158008

Mingliang Zheng

{"title":"Research on time-varying reliability of wind power gearbox with failure correlation","authors":"Mingliang Zheng","doi":"10.15632/jtam-pl/158008","DOIUrl":"https://doi.org/10.15632/jtam-pl/158008","url":null,"abstract":"In the process of reliability modeling and design of a wind power gearbox, the inﬂuence of failure correlation of system components and random dynamic loads can not be ignored. In this paper, taking the output power of each shaft of the gearbox as the starting point, distribution parameters of stress and strength for critical failed components (gear and bearing) of the gearbox are solved. After normalization of these parameters, and when there is a linear correlation between the loads of each component, ﬁnally, the time-varying reliability related to failure correlation is calculated based on a full probability diﬀerential method by using the stress strength interference theory at the system level, and the results are veriﬁed by the Monte-Carlo simulation method. It is found that the failure correlation caused by the external dynamic loads between components can signiﬁcantly reduce reliability of the gearbox system. The stronger the correlation, the lower the reliability of the gearbox system. Meanwhile, the time-varying reliability conforms to characteristics of the “failure bathtub curve” of typical mechanical products. This paper can lay a foundation for the time-varying reliability optimization design and structural robustness design of the wind power gearbox.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"13 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83693593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Analysis of progressive collapse of a super-long span latticed steel arch structure 某超长跨度网架钢拱结构连续倒塌分析

IF 0.7 4区工程技术

Journal of Theoretical and Applied Mechanics Pub Date : 2023-01-18 DOI: 10.15632/jtam-pl/157311

Shuang-quan Guo, Delin Xu, Kaiguang Shang, Shuo Yang, Di Wang, Geng Li, B. Zheng, Yong Jiao

{"title":"Analysis of progressive collapse of a super-long span latticed steel arch structure","authors":"Shuang-quan Guo, Delin Xu, Kaiguang Shang, Shuo Yang, Di Wang, Geng Li, B. Zheng, Yong Jiao","doi":"10.15632/jtam-pl/157311","DOIUrl":"https://doi.org/10.15632/jtam-pl/157311","url":null,"abstract":"The progressive collapse of a space grid structure which has a large number of members and a large span is the focus of current research. Before the progressive collapse of the structure, there is a problem of instability of the members. In this paper, dynamic nonlinear analysis of a super-long span latticed steel arch structure is carried out to study its progressive collapse process using a Kinematic Hardening Plasticity constitutive model compiled by Vumat material subprogram in Abaqus, which takes into account instability of the members. Diﬀerences in the dynamic response process of the structure at the collapse moment and the failure sequence of the members using the member stability model and the material failure constitutive model are compared. Compared with the material failure constitutive model, when the member stability constitutive model is used, the proportion of compressive buckling members in the structural failure is higher, and the bearing capacity of the structure is lower when the initial failure occurs. The structure suﬀers from localized member compressive failure rather than material yielding, which leads to the progressive collapse of the structure.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"115 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80581773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

On the yield surface of a typical bending-dominant periodic lattice metamaterial 典型弯曲优势周期晶格超材料的屈服面

IF 0.7 4区工程技术

Journal of Theoretical and Applied Mechanics Pub Date : 2023-01-18 DOI: 10.15632/jtam-pl/158574

Yongjun Wang, Jinxing Liu

引用次数: 0

Research on creep-fatigue model of anchored jointed rock mass 锚固节理岩体蠕变疲劳模型研究

IF 0.7 4区工程技术

Journal of Theoretical and Applied Mechanics Pub Date : 2023-01-17 DOI: 10.15632/jtam-pl/157510

Yang Song, B. Fan, Yongqi Li, Heping Wang

引用次数: 0

Predictions of fracture resistance of spruce wood under mixed mode loading using non-local fracture theory and numerical modelling 基于非局部断裂理论和数值模拟的混合模式载荷下云杉木材断裂抗力预测

IF 0.7 4区工程技术

Journal of Theoretical and Applied Mechanics Pub Date : 2023-01-08 DOI: 10.15632/jtam-pl/158823

M. Romanowicz

引用次数: 0

Research on vibration evolution of a ball bearing without the cage under local variable-diameter raceway damage 局部变径滚道损伤下无保持架球轴承振动演化研究

IF 0.7 4区工程技术

Journal of Theoretical and Applied Mechanics Pub Date : 2023-01-05 DOI: 10.15632/jtam-pl/157462

Enwen Zhou, Yanling Zhao, Huanqing Zhang

引用次数: 0

Analytical study on the cutting force and residual stress in whirlwind milling of a large screw 大型螺杆旋风铣削切削力和残余应力的分析研究

IF 0.7 4区工程技术

Journal of Theoretical and Applied Mechanics Pub Date : 2023-01-03 DOI: 10.15632/jtam-pl/157479

Qin Guo, Yulin Wang, Bin Zhou

引用次数: 1

Study on the stress intensity factor of a compact specimen under the pre-compressed load condition 预压缩载荷条件下压实试样的应力强度因子研究

IF 0.7 4区工程技术

Journal of Theoretical and Applied Mechanics Pub Date : 2023-01-03 DOI: 10.15632/jtam-pl/157556

Dongquan Wu, Zixiang Liu, Dinghe Li, Zhiqiang Zhang, Jianguo Chen

{"title":"Study on the stress intensity factor of a compact specimen under the pre-compressed load condition","authors":"Dongquan Wu, Zixiang Liu, Dinghe Li, Zhiqiang Zhang, Jianguo Chen","doi":"10.15632/jtam-pl/157556","DOIUrl":"https://doi.org/10.15632/jtam-pl/157556","url":null,"abstract":"Structural components are often operated under combined stress conditions (primary and secondary stresses), but the stress levels generated by residual stress (or secondary stress) is hardly ever evaluated. Hence, stress intensity factors at the crack tips of a compact tension (CT) specimen under a pre-compressed load condition are analyzed using the ﬁnite element method. Then, the average residual stress intensity factor is calculated and analyzed. As the crack length a 0 /W increases, the average residual stresses σ ave /σ 0 grows under the same pre-compression load. σ ave /σ 0 increases rapidly at a low range of the pre-compression load but tends to a constant in a high range of the load. The distribution of the average residual stress intensity factors K ave and σ ave /σ 0 of the CT specimen with same crack length under diﬀerent pre-compression loads have the same tendency. Additionally, the distribution of K ave and K FEM under diﬀerent pre-compression loads are also similar. Nevertheless, K ave estimated by the average residual stress is too conservative and not accurate, and the method is complex, which depends on the analysis of simulation. Therefore, a simple method for calculating Mode I stress intensity factor K for this model is presented. A group of examples is presented to verify the accuracy of the method.","PeriodicalId":49980,"journal":{"name":"Journal of Theoretical and Applied Mechanics","volume":"29 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2023-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74655668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0