检索结果-内蒙古大学图书馆

Effect of a gap on the open hole tension strength of carbon fiber reinforced plastic laminates

JOURNAL OF COMPOSITE MATERIALS 2023年第21期57卷 3377-3391页

作者： Suemasu, Hiroshi Aoki, Yuichiro Tateishi, Yasutomo Sugimoto, Sunao Nakamura, Toshiya Japan Aerosp Explorat Agcy Aeronaut Technol Directorate Tokyo Japan Nihon Emsco Co Ltd Tokyo branch Off Tokyo Japan Japan Aerosp Explorat Agcy Aeronaut Technol Directorate 6-13-1 Osawa Mitaka Tokyo 1810015 Japan

Tensile tests of quasi-isotropic laminates with a circular open hole, which include a gap in the hole area, were conducted to demonstrate the effect of the gap on the strength. The test showed that the reduction in the open-hole strength owing to the gap was less significant than that in the no-hole tensile strength. A two-dimensional mechanical model of quasi-isotropic laminates with an arbitrary inclined gap was proposed and analytically solved to obtain a closed-form expression for the stress concentration. An approximate expression was provided as the sum of the global uniform stress field and the local stress field near the open hole, which was solved based on a complex variable method. The present analytical solution agrees well with the corresponding two-dimensional finite element solutions. The solution indicated that the stress increase owing to the gap is limited at the stress concentration area. The analytical results were consistent with the experimental results.

关键词： Structural composites automated fiber placement technique defects stress concentrations complex variable method finite element method

来源：评论

学校读者我要写书评

暂无评论

Analytical solutions on non-Darcy seepage of grouted and lined subsea tunnels under dynamic water levels

引用

OCEAN ENGINEERING 2023年 267卷

作者： Liu, Xiang Wang, Dongchi Zhang, Yu Jiang, Annan Fang, Qian Zhang, Rui Dalian Maritime Univ Coll Transportat Engn Dalian 116026 Peoples R China Beijing Jiaotong Univ Key Lab Urban Underground Engn Minist Educ Beijing 100044 Peoples R China Beijing Urban Construct Grp Co Ltd Beijing 100088 Peoples R China

For the grouted and lined subsea tunnels, the fluid in the low permeability media follows non-Darcy's law rather than Darcy's law. To address this, we provide analytical solutions for the grouted and lined subsea tunnel with dynamic water levels. Our method uses complex variable functions and Hansbo non-Darcy seepage model. The analytical solutions divide into three cases according to the critical water inflow and can degenerate into the traditional method following Darcy's law. The numerical simulation, experimental data, in-situ data, and other analytical solutions are adopted to verify our proposed method. The calculated results subjected to non-Darcy seepage are close to the in-situ data compared with other analytical solutions. When degenerating into the traditional method, the results agree well with those of previous methods following Darcy's law. It reveals that our method is suitable and universal. The parametric analyses of the non-linear flow index m, the critical hydraulic gradient il, the dynamic water level xi ci, the thickness of lining zone tl, and the relative permeability coefficient ratio of the grouting zone and lining zone kg/kl are carried out. The results show that non-linear seepage parameters and dynamic water levels significantly affect the water inflow and water head. The denser grouting material can apportion more water heads and make the lining apportion fewer water heads to protect the lining from fluctuation influencing of dynamic water levels.

关键词： Subsea tunnel Non -Darcy seepage Grouting and lining Dynamic water level complex variable method

来源：评论

学校读者我要写书评

暂无评论

A screw dislocation in a three-phase composite composed of an anisotropic elastic half-plane bonded to an isotropic elastic half-plane reinforced by a circular inhomogeneity

引用

MATHEMATICS AND MECHANICS OF SOLIDS 2023年第8期28卷 1834-1844页

作者： Wang, Xu Schiavone, Peter East China Univ Sci & Technol Sch Mech & Power Engn 130 Meilong Rd Shanghai 200237 Peoples R China Univ Alberta Dept Mech Engn 10-203 Donadeo Innovat Ctr Engn Edmonton AB T6G 1H9 Canada

Using complex variable techniques, we solve the problem in anti-plane elasticity associated with a screw dislocation in a three-phase composite which is composed of an anisotropic elastic half-plane perfectly bonded to an isotropic elastic half-plane containing a circular elastic inhomogeneity. Analytical solutions are obtained for three typical cases: a screw dislocation in the isotropic half-plane in the exterior of the circular inhomogeneity, a screw dislocation inside the circular elastic inhomogeneity, a screw dislocation within the anisotropic half-plane. Explicit expressions of the image force acting on the screw dislocation are derived for each of the three cases. The numerical results indicate that at least one equilibrium position for the screw dislocation co-exists in each phase under certain conditions on the elastic constants.

关键词： Three-phase composite screw dislocation image force complex variable method equilibrium position anisotropic elasticity isotropic elasticity

来源：评论

学校读者我要写书评

暂无评论

Using Laurent's series in the theoretical solution to estimate the stress resultants of FG-CNTRC plates weakened by a central cutout at different temperatures

引用

INTERNATIONAL JOURNAL FOR COMPUTATIONAL methodS IN ENGINEERING SCIENCE & MECHANICS 2023年第4期24卷 227-246页

作者： Zeighami, Vahid Jafari, Mohammad Jafari, Mohammad Shahrood Univ Technol Dept Mech & Mechatron Engn Shahrood Iran New Jersey Inst Technol Dept Mech & Ind Engn Newark NJ USA

Conventional ordinary materials have many weaknesses when exposed to extreme loadings. Hence, scientists develop novel engineered materials to address these weaknesses. Functionally Graded Carbon Nanotube Reinforced Composites (FG-CNTRCs) are a modern group of materials that have recently flourished thanks to their excellent and unique mechanical properties. One common loading condition is subjecting FG-CNTRC plates containing cutouts to in-plane loadings. The presence of an opening disturbs the stress field, especially in the proximity of the cutout, and creates stress concentration. This study estimates the stress and moment resultants on the edge of elliptical cutouts in asymmetric FG-CNTRC plates under various loading conditions using a new analysis based on Lekhnitskii's complex variables method, mapping function, and Laurent series. Unlike previous studies on perforated asymmetric plates, which were based on numerical methods or the Schwartz formulations, this study presents a new solution using Laurent's series to represent the holomorphic function. In calculating the stress and moment components around the opening, the effect of determining variables is studied. This approach can be generalized to solve different anisotropic body problems (FG_CNTRC, FGM, Laminate composites). Thus, stress and moment components in perforated anisotropic plates can be determined simply and systematically using this method.

关键词： Perforated functionally graded plate potential functions complex variable method stress resultants and moments CNTRC

来源：评论

学校读者我要写书评

暂无评论

Thermoelectric field for a coated hole of arbitrary shape in a nonlinearly coupled thermoelectric material

引用

Applied Mathematics and Mechanics(English Edition) 2022年第11期43卷 1691-1700页

作者： Xu WANG P.SCHIAVONE School of Mechanical and Power Engineering East China University of Science and TechnologyShanghai 200237China Department of Mechanical Engineering University of Alberta10-203 Donadeo Innovation Center for EngineeringEdmonton T6G 1H9Canada

We study the thermoelectric field for an electrically and thermally insulated coated hole of arbitrary shape embedded in an infinite nonlinearly coupled thermoelectric material subject to uniform remote electric current density and uniform remote energy flux.A conformal mapping function for the coating and matrix is introduced,which simultaneously maps the hole boundary and the coating-matrix interface onto two concentric circles in the image *** analytic continuation,we derive a general solution in terms of two auxiliary *** general solution satisfies the insulating conditions along the hole boundary and all of the continuity conditions across the perfect coating-matrix *** the two auxiliary functions have been obtained in the elementary-form,the four original analytic functions in the coating and matrix characterizing the thermoelectric fields are completely and explicitly *** design of a neutral coated circular hole that does not disturb the prescribed thermoelectric field in the thermoelectric matrix is achieved when the relative thickness parameter and the two mismatch parameters satisfy a simple ***,the neutrality of a coated circular thermoelectric inhomogeneity is also accomplished.

关键词： thermoelectric material nonlinear coupling coated hole of arbitrary shape complex variable method analytic solution neutral coated hole

来源：评论

学校读者我要写书评

暂无评论

Fracturing process and initiation mechanism of hard rock tunnels with different shapes: particle flow modeling and analytical study

引用

COMPUTATIONAL PARTICLE MECHANICS 2023年第6期10卷 1859-1875页

作者： Wu, Hao Fan, Aoqi Ma, Dan Spearing, A. J. S. Zheng, Zhi China Univ Min & Technol Sch Mines Xuzhou 221116 Peoples R China Guangxi Univ Guangxi Key Lab Disaster Prevent & Engn Safety Nanning 530004 Peoples R China Guangxi Univ Key Lab Disaster Prevent & Struct Safety Minist Educ Nanning 530004 Peoples R China Yunnan Phosphate Chem Grp Co Ltd Kunming 650600 Peoples R China

Rock-related disasters such as roof falls, sidewall spalling, and rock bursts are commonly encountered in hard rock tunnels, resulting in frequent occurrence of tunnel instability in tunneling and mining engineering. To improve the understanding of failure mechanism in hard tunnels, rocks containing one single hole with five cross-sectional shapes (circle, horseshoe, trapezoid, trapezoid and square) were modeled using the PFC (Particle Flow Code) program. Then, a series of biaxial compression tests with confining pressures of 0 MPa, 5 MPa, 10 MPa, 20 MPa and 40 MPa were conducted on these models to explore the influence of cross-sectional shape and stress condition on fracturing behavior of tunnels. Afterward, the analytical solutions of stress around the holes in rocks under different stress states were derived by the complex variable function method to interpret the fracture initiation mechanism. The results show that the mechanical property and fracturing characteristics are highly related to the hole shape and confining pressure. A total of four kinds of fractures emerges in sequence around the holes under uniaxial loading, i.e., primary tensile fracture, spalling fracture, remote fracture and shear fracture. With the growing of confining stress, the formation of tensile fractures is limited, while the initiation of the spalling fracture becomes more severe. Also, the failure mode of the pre-holed models shifts from shear failure to spalling failure. Besides, the analytical results of surrounding stress, namely tensile stress and compressive stress, distribute on the roofs/floors and sides of the holes under low lateral stress, whilst the law in case of high lateral stress is opposite, strongly explain the fracturing behavior. The research results have important guiding value for the comprehension of the fracturing behavior of rock tunnels whose axes are parallel to one of the principal stresses.

关键词： Fracturing process Hard rock tunnel Failure mode PFC modeling complex variable method Stress analysis

来源：评论

学校读者我要写书评

暂无评论

A novel method for estimation of stress concentration factor of central cutouts located in orthotropic plate

引用

JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING 2021年第7期43卷 1-13页

作者： Abbasnia, Ali Jafari, Mohammad Rohani, Abbas Shahrood Univ Technol Fac Mech & Mechatron Engn Shahrood Iran Ferdowsi Univ Mashhad Dept Biosyst Engn Fac Agr Mashhad Razavi Khorasan Iran

The purpose of this paper is to present a new method based on the regression analysis for estimating stress concentration factor of different cutouts in orthotropic plates. The existence of an explicit relation in terms of mechanical properties can be an approach for analyzing the stress of viscoelastic plates. Little research has been conducted to provide explicit relationships to calculate the theoretical stress concentration. In the present study first, using different values of the mechanical properties of the composites, stress concentration factor was calculated by employing an analytical solution based on the complex variable method. Then, using multiple linear regression, an explicit mathematical relation for different cutouts was presented with the purpose of estimating stress concentration factor in terms of mechanical properties. The results showed that the regression model is able to predict circumferential stress with a maximum error of 1% for circular, elliptical, triangular and square cutouts. Also, the evaluation of the model with k-fold cross validation method and also comparison with other studies showed that it is possible to rely on the present estimation. Working with the regression models, which are presented in this article, is very simple and can be practical. Graphic abstract

关键词： Stress concentration factor Composites Orthotropic plate Multiple linear regression complex variable method

来源：评论

学校读者我要写书评

暂无评论

In-plane deformations of a circular elastic inhomogeneity with an eccentric interphase layer

引用

ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK 2022年第3期73卷 101-101页

We use complex variable methods to derive an analytical solution to the problem in plane elasticity associated with a circular elastic inhomogeneity with an eccentric interphase layer when the matrix is subjected to uniform remote in-plane stresses and the interphase layer undergoes uniform in-plane eigenstrains. The complex coefficients appearing in all three pairs of analytic functions characterizing the elastic fields in the composite are uniquely determined by solving two decoupled sets of linear algebraic equations obtained by enforcing the continuity conditions of tractions and displacements across the two perfect circular interfaces with the aid of analytic continuation. A simple analytical solution is also derived when the circular inhomogeneity becomes a traction-free hole and the interphase layer and the matrix have equal shear modulus but distinct Poisson's ratios. The non-uniform mean stress inside the circular inhomogeneity and the hoop stress along the edge of the circular hole are calculated and illustrated graphically.

关键词： Eccentric coating Circular inhomogeneity complex variable method Conformal mapping Analytic continuation Mean stress

来源：评论

学校读者我要写书评

暂无评论

The critical behaviour of finite thickness lining systems in tunnels

引用

EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING 2022年第8期26卷 3313-3330页

作者： Dong, Xiangjian Karrech, Ali Qi, Chongchong Basarir, Hakan Elchalakani, Mohamed Univ Western Australia Dept Civil Environm & Min Engn Crawley WA 6009 Australia

Lining is gaining acceptance in underground excavations because of its reinforcing and protecting capacities. The purpose of this paper was to derive an analytic expression based on the complex variable method to describe the behaviour of a tunnel with a liner of finite thickness. The stress functions have been expressed as Laurent series where the infinite undetermined coefficients are obtained using force and displacement boundary conditions at the inner face, liner-rock interface and far-field boundaries. The finite element method has been used to verify the proposed solution;a good agreement has been obtained both in the surrounding rock mass and within the liner. In addition, based on the verified solution, the liner effect on the critical position of the interface has been investigated by applying Mohr-Coulomb's failure criterion. A detailed parametric study shows that the relative liner thickness, relative stiffness and lateral stress coefficient have a great influence on the failure position, while the internal friction angle of the rock has a slight effect on the results. The proposed analytical solution is not restricted to the liner thickness, and the stress distribution within the liner is obtained accordingly;the solution can be generalised to other applications such as backfill analysis by setting the liner thickness equal to the radius of the opening.

关键词： Lined opening failure criterion complex variable method deep excavation

来源：评论

学校读者我要写书评

暂无评论

Analytical solution for stress and displacement of a finite thickness soil layer subjected to strip footing

引用

APPLIED MATHEMATICAL MODELLING 2022年 108卷 553-566页

作者： Zhang, Min Lu, Aizhong Ma, Yaocai Sha, Xiangyu North China Elect Power Univ Inst Hydroelect & Geotech Engn 2 Beinong Rd Huilongguan Beijing 102206 Peoples R China

Consider an elastic soil layer with a shallow-buried strip footing at the upper boundary and bedrock at the lower boundary, the displacement along the contact surface between the soil layer and the bedrock can be considered as zero when the bedrock is sufficiently rigid relative to the soil layer. The stress and displacement fields in the soil layer are solved on the premise that the displacement on the contact surface between the soil layer and the strip footing is given. The soil layer with the finite thickness on the physical plane is mapped onto the inner domain of the unit circle on the image plane based on the conformal transformation. Then, the complex variable method is applied to give the stress and displacement fields in the soil layer by two analytic functions, the coefficients of which can be determined by the stress and displacement boundary conditions on the upper and lower boundaries of the soil layer. In calculation, the power series method is introduced to establish a set of linear equations containing the analytic function coefficients, and then the coefficients are determined by solving the linear equations. This paper presents the analytical solutions of stress and displacement in the soil layer under two different displacement boundary conditions on the contact surface between the soil layer and the footing. The obtained results are compared with the results of the numerical method based on ANSYS. Finally, the influence of different displacement boundary conditions and soil thickness on the stresses on the surface and internal region of the soil layer is analyzed. (c) 2022 Elsevier Inc.

关键词： Strip footing Soil layer complex variable method Stress and displacement Analytical solution

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：