检索结果-南通市图书馆

Large deflection of clamped circular plate and accuracy of its approximate analytical solutions

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2016年第2期59卷 67-77页

作者： yin zhang State Key Laboratory of Nonlinear Mechanics(LNM) Institute of Mechanics Chinese Academy of Sciences

A different set of governing equations on the large deflection of plates are derived by the principle of virtual work(PVW), which also leads to a different set of boundary conditions. Boundary conditions play an important role in determining the computation accuracy of the large deflection of plates. Our boundary conditions are shown to be more appropriate by analyzing their difference with the previous ones. The accuracy of approximate analytical solutions is important to the bulge/blister tests and the application of various sensors with the plate structure. Different approximate analytical solutions are presented and their accuracies are evaluated by comparing them with the numerical results. The error sources are also analyzed. A new approximate analytical solution is proposed and shown to have a better approximation. The approximate analytical solution offers a much simpler and more direct framework to study the plate-membrane transition behavior of deflection as compared with the previous approaches of complex numerical integration.

关键词： approximate analytical solutions large deflection plate membrane bulge and blister tests

The Mexican hat effect on the delamination buckling of a compressed thin film

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2014年第6期30卷 927-932页

作者： yin zhang Yun Liu State Key Laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Faculty of Information and Automation Kunming University of Science and Technology

Because of the interaction between film and substrate,the film buckling stress can vary significantly,depending on the delamination geometry,the film and substrate mechanical *** Mexican hat effect indicates such *** analytical method is presented,and related dimensional analysis shows that a single dimensionless parameter can effectively evaluate the effect.

关键词： Buckling Delamination Elastic foundation Thin film Compliant substrate

Design and Analysis of Electro-mechanical Hybrid Anti-lock Braking System for Hybrid Electric Vehicle Utilizing Motor Regenerative Braking

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2009年第1期22卷 42-49页

作者： zhang Jianlong yin Chengliang zhang Jianwu School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China

Braking on low adhesion-coefficient roads, hybrid electric vehicle＇s motor regenerative torque is switched off to safeguard the normal anti-lock braking system （ABS） fimction. When the ABS control is terminated, the motor regenerative braking is readmitted. Aiming at avoiding permanent cycles from hydraulic anti-lock braking to motor regenerative braking, a novel electro-mechanical hybrid anti-lock braking system using fuzzy logic is designed. Different from the traditional single control structure, this system has a two-layered hierarchical structure, The first layer is responsible for harmonious adjustment or interaction between regenerative system and anti-lock braking system. The second layer is responsible for braking torque distribution and adjustment. The closed-loop simulation model is built. Control strategy and method for coordination between regenerative and anti-lock braking are developed. Simulation braking on low adhesion-coefficient roads with fuzzy logic control and real vehicle braking field test are presented. The results from simulating analysis and experiment show braking performance of the vehicle is perfect, harmonious coordination between regenerative and anti-lock braking function, significant amount of braking energy can be recovered and the proposed control strategy and method are effective.

关键词： hybrid electric vehicle regenerative braking anti-lock braking fuzzy logic control electro-mechanical hybrid anti-lock braking

Lipschitz-continuity of Spherically Convex Functions

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2023年第2期39卷 363-374页

作者： yin zhang Qi GUO Department of Mathematics Suzhou University of Science and TechnologySuzhou215009China

In this article,some basic and important properties of spherically convex functions,such as the Lipschitz-continuity,are *** is shown that,under a weaker condition,every family of spherically convex functions is equi-Lipschitzian on each closed spherically convex subset contained in the relative interior of their common domain,and from which a powerful result is derived:the pointwise convergence of a sequence of spherically convex functions implies its uniform convergence on each closed spherically convex subset contained in the relative interior of their common domain.

关键词： Spherically convex set spherically convex function Lipschitz-continuity uniform convergence

Theory of Compressive Sensing via l1-Minimization:a Non-RIP Analysis and Extensions

在线全文

学校读者我要写书评

暂无评论

Journal of the Operations Research Society of China 2013年第1期1卷 79-105页

作者： yin zhang Department of Computational and Applied Mathematics Rice University6100 MainHoustonTX 77005USA

Compressive sensing(CS)is an emerging methodology in computational signal processing that has recently attracted intensive research *** present,the basic CS theory includes recoverability and stability:the former quantifies the central fact that a sparse signal of length n can be exactly recovered from far fewer than n measurements via l1-minimization or other recovery techniques,while the latter specifies the stability of a recovery technique in the presence of measurement errors and inexact *** far,most analyses in CS rely heavily on the Restricted Isometry Property(RIP)for *** this paper,we present an alternative,non-RIP analysis for CS via *** purpose is three-fold:(a)to introduce an elementary and RIP-free treatment of the basic CS theory;(b)to extend the current recoverability and stability results so that prior knowledge can be utilized to enhance recovery via l1-minimization;and(c)to substantiate a property called uniform recoverability of l1-minimization;that is,for almost all random measurement matrices recoverability is asymptotically *** the aid of two classic results,the non-RIP approach enables us to quickly derive from scratch all basic results for the extended theory.

关键词： Compressive sensing l1-Minimization Non-RIP analysis Recoverability and stability Prior information Uniform recoverability

Convergence of a Class of Stationary Iterative Methods for Saddle Point Problems

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of the Operations Research Society of China 2019年第2期7卷 195-204页

作者： yin zhang Institute for Data and Decision Analytics The Chinese University of Hong KongShenzhen 518172China Department of Computational and Applied Mathematics Rice UniversityHouston 77005United States of America

A unified convergence theory is derived for a class of stationary iterative methods for solving linear equality constrained quadratic programs or saddle point *** class is constructed from essentially all possible splittings of the submatrix residing in the(1,1)-block of the augmented saddle point matrix that would produce non-expansive *** classic augmented Lagrangian method and alternating direction method of multipliers are two special members of this class.

关键词： Saddle point problem Quadratic program Matrix splitting Stationary iterations Spectral radius Q-linear convergence

JUMPING INSTABILITIES IN THE POST-BUCKLING OF A BEAM ON A PARTIAL NONLINEAR FOUNDATION

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2013年第5期26卷 500-513页

作者： yin zhang Kevin D Murphy State Key Laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Department of Mechanical Engineering University of Connecticut

Mode jumping is an instability phenomenon in the post-buckling region, which causes a sudden change in the equilibrium configuration and is thus harmful to structure. The con- figuration of a partial elastic foundation can directly induce mode coupling from the buckling stage and through the whole post-buckling region. The mode coupling effect due to the configuration of partial foundation on mode jumping is investigated and demonstrated to be an important factor of determining mode jumping. By properly choosing the partial elastic foundation configuration, mode jumping can be avoided.

关键词： instability mode jumping tertiary jumping buckling beam elastic foundation

Striking 2D materials: exfoliation of molecular crystals

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2022年第6期65卷 1005-1006页

作者： yin zhang Shengqian Ma Department of Chemistry University of North TexasDentonTX76201USA

Ultrathin nanosheets, which are often prepared from bulk crystals by exfoliating, represent an intriguing type of twodimensional (2D) materials with mechanical, electronic,optical, and thermal properties that are distinct from their pristine bulk crystals. They are promising in various applications, including (opto)electronics, chemical sensing, catalysis, and separation, because of their unique properties and high surface area. Previously, the operationally simple exfoliation method is only applicable to bulk crystals with weak interactions between the layers.

关键词： crystals separation catalysis

同方期刊数据库

LOCAL BENDING OF THIN FILM ON VISCOUS LAYER

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2010年第2期23卷 106-114页

作者： yin zhang Yun Liu State Key Laboratory of Nonlinear Mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100190 China Faculty of Information and Automation Kunming University of Science and Technology Kunming 650051 China

Effects of deposition layer position film are systematically investigated. Because the and number/density on local bending of a thin deposition layer interacts with the thin film at the interface and there is an offset between the thin film neutral surface and the interface, the deposition layer generates not only axial stress but also bending moment. The bending moment induces an instant out-of-plane deflection of the thin film, which may or may not cause the socalled local bending. The deposition layer is modeled as a local stressor, whose location and density are demonstrated to be vital to the occurrence of local bending. The thin film rests on a viscous layer, which is governed by the Navier-Stokes equation and behaves like an elastic foundation to exert transverse forces on the thin film. The unknown feature of the axial constraint force makes the governing equation highly nonlinear even for the small deflection chse. The constraint force and film transverse deflection are solved iteratively through the governing equation and the displacement constraint equation of immovable edges. This research shows that in some special cases, the deposition density increase does not necessarily reduce the local bending. By comparing the thin film deflections of different deposition numbers and positions, we also present the guideline of strengthening or suppressing the local bending.

关键词： local bending deposition layer/dot thin film viscous layer constraint