检索结果-内蒙古大学图书馆

An efficient generic direct integration method for the generalized damping structure dynamic system

MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2025年 224卷

作者： Shen, Renjie Liu, Junjie Xu, Lixin Jiangsu Univ Sci & Technol Sch Naval Architecture & Ocean Engn Dept Engn Mech Zhenjiang Peoples R China Jiangsu Univ Sci & Technol Ocean Coll Zhenjiang Peoples R China Jiangsu Marine Technol Innovat Ctr Nantong Peoples R China

Generalized damping is a time-memory nonlocal model that takes the complete history velocity into account through a convolution. The kernel function of the convolution represents the distribution or the weight of history velocity in the time dimension. In this work, a high-efficiency algorithm is proposed for the calculation of generalized damping convolution. In this algorithm, the kernel function in the convolution is approximated by Fourier series. The relationship between the second derivative of the convolution and the convolution itself has been established. The derivative of the convolution is computed through multi-points difference scheme. This algorithm combined with direct time integration method is a generic method that can be applied for any causal kernel functions. By analyzing the computational complexity of different methods, it can be seen that the computational complexity of the existing methods is not only related to the number of degrees of freedom of the system, but also has a quadratic or cubic relationship with the number of computational steps. The computational efficiency of the proposed method is only related to the number of degrees of freedom of the system, not the number of steps, its efficiency is higher than that of the existing direct integration methods. Numerical examples are provided to illustrate the accuracy and especially the efficiency of the integration.

关键词： direct integration method Generalized damping Efficient algorithm Kernel function

来源：评论

学校读者我要写书评

暂无评论

Explicit thermal analysis of inhomogeneous multilayer cylinders using the direct integration method

引用

INTERNATIONAL JOURNAL OF THERMAL SCIENCES 2024年 196卷

作者： Tokovyy, Yuriy, V Hrytsyna, Olha R. Hrytsyna, Maryan R. Natl Acad Sci Ukraine Pidstryhach Inst Appl Problems Mech & Math 3-B Naukova St UA-79060 Lvov Ukraine Slovak Acad Sci Inst Construct & Architecture Dubravska Cesta 9 Bratislava 45 Slovakia

A technique for analyzing two-dimensional thermal fields in hollow cylinders is presented when the cylinders are assembled of a number of perfectly connected coaxial layers made of dissimilar materials exhibiting arbitrarily continuous radial variation of their thermophysical properties. Making use of the direct integration method allows for reducing the original heat conduction equation with stepwise variable coefficients to the integral equations of the second kind with solution constructed through the resolvent-kernel technique in the form of explicit dependences on the applied thermal loading on the inner and outer circumferences of the cylinders and the internal heat sources. This approach allows for constructing a solution from the "single-solid" standpoint and thus is efficient for an arbitrary number of layers exhibiting inhomogeneous properties. On the other hand, the application of this technique does not involve the generalized-derivative apparatus typical for the use of single -solid methods. The applicability of the proposed solution for the verification of homogenization models for stratified cylinders is demonstrated by the considered case studies.

关键词： Inhomogeneous multilayer cylinders Temperature direct integration method Integral equations Explicit-form solutions

来源：评论

学校读者我要写书评

暂无评论

Stabilization of chaotic systems via act-and-wait delayed feedback control using a high-precision direct integration method

引用

SN APPLIED SCIENCES 2020年第4期2卷 1-10页

作者： Liu, Dasheng Yan, Guozheng Shanghai Jiao Tong Univ Sch Elect Informat & Elect Engn Dept Instrument Sci & Engn Shanghai 200240 Peoples R China Shanghai Jiao Tong Univ Natl Ctr Translat Med Collaborat Innovat Ctr Syst Biol Shanghai 200240 Peoples R China

A technique for the numerical analysis of the stability problem in chaotic systems via act-and-wait delayed feedback control is developed and justified. Recently, act-and-wait modification of a delayed feedback control method is proposed to stabilize unstable periodic orbits in dynamical systems. To overcome the difficulties in obtaining conditions under which the state of closed-loop system converges toward a periodic solution via the act-and-wait scheme, this paper presents a high-precision direct integration method for calculating the monodromy matrix corresponding to the closed-loop system based on the theory of Peano-Baker series. The capabilities of the proposed schemes in stabilization of unstable periodic orbits of chaotic systems are illustrated by numerical examples.

关键词： Chaos control Delayed feedback control direct integration method Act-and-wait Monodromy matrix

来源：评论

学校读者我要写书评

暂无评论

Modified precise direct time integration method for the transient response analysis of viscoelastic systems using an internal variable model

引用

JOURNAL OF VIBRATION AND CONTROL 2020年第3-4期26卷 161-174页

作者： Abbasi, Taufeeq Ur Rehman Zheng, Hui Shanghai Jiao Tong Univ State Key Lab Mech Syst & Vibrat Inst Vibrat Shock & Noise Shanghai Peoples R China

Engineering systems for different levels of energy dissipation use internal variable models, which may lead to tremendous problems in accurate analysis. This article aims to provide an alternative direct integration method for the analysis of systems involving an anelastic displacement field model. A new state-space formulation built on an augmented set of anelastic variables for asymmetric systems is developed. Then, a precise time integration method based on state-space matrix formulation is proposed by introducing a Legendre-Gauss quadrature. The new integration method in terms of numerical stability and its implementation is discussed. The effect of sensitivity of the selection of the time-step and computational time on the performance of the new method is investigated by using a multi-degree-of-freedom system. The performance of the new method is also evaluated in terms of both computational accuracy and efficiency at higher degrees of freedom by using a continuum system. It is demonstrated that the computational accuracy and efficiency of the new method on large-scale problems are higher than that of the direct integration linear displacement-velocity method.

关键词： Transient response analysis state-space formulation direct integration method stability analysis accuracy analysis computational efficiency

来源：评论

学校读者我要写书评

暂无评论

Investigation of the Free Vibrations of Bar Elements with Variable Parameters Using the direct integration method

引用

STRENGTH OF MATERIALS 2016年第3期48卷 384-393页

作者： Shvab'yuk, V. I. Krutii, Yu. S. Sur'yaninov, M. G. Lutsk Natl Tech Univ Lutsk Ukraine Odessa State Acad Civil Engn & Architecture Odessa Ukraine

The vibration analysis of bar element systems with continuous variable parameters using the direct integration method is proposed. The method is based on analytical solutions of the appropriate differential equations. By using this method, the problem of free flexural vibrations of a straight bar with arbitrary, continuously varying transverse stiffness and mass per unit length is solved. Formulas in analytical form are derived for dynamic parameters of bar structures, and the procedure for their numerical implementation is presented. Free vibrations of a truncated cone and chimney with a variable wall thickness are studied.

关键词： direct integration method analytical solutions transverse beam vibrations vibration coefficients vibration frequencies chimney vibration

来源：评论

学校读者我要写书评

暂无评论

Elastic and thermoelastic response of multilayer inhomogeneous hollow cylinders

引用

MECHANICS OF ADVANCED MATERIALS AND STRUCTURES 2024年第17期31卷 3889-3901页

作者： Tokovyy, Yuriy V. Natl Acad Sci Ukraine Pidstryhach Inst Appl Problems Mech & Math 3-B Naukova St UA-79060 Lvov Ukraine

An approach is presented for solving plane axisymmetric problems of elasticity and thermoelasticity for multilayer hollow cylinders with per-layer properties having arbitrary distribution profiles within the radial coordinate. The approach is based on the representation of material profiles within the entire assembly in the form of stepwise-variable functions with the implication of the direct integration method toward the compatibility equation in terms of strains. The approach avoids using the generalized derivative apparatus. The original problems are reduced to a governing integral equation with an integral condition implying a solution through explicit dependence on the force and thermal loadings.

关键词： Multilayer hollow cylinders inhomogeneous material FGM direct integration method explicit solution

来源：评论

学校读者我要写书评

暂无评论

Time-dependent reliability calculation method of RC bridges based on the dual neural network

引用

SOFT COMPUTING 2023年第13期27卷 8855-8866页

作者： Yang, Yong Li, Haibin Inner Mongolia Univ Technol Coll Sci Hohhot Peoples R China Inner Mongolia Univ Technol Engn Training Ctr Hohhot Peoples R China

Time-dependent reliability is a key index for reliability evaluation and life prediction of existing bridges, which can reflect the service status of bridges. Therefore, the time-dependent reliability of the bridge must be calculated and analyzed in time to ensure the safety of the bridge. Many scholars have established different time-dependent reliability models, but the model contains complex multiple integrals and is difficult to calculate. In this case, the current method for calculating time-dependent reliability is Monte Carlo method, which is inefficient and cannot meet the engineering needs. In order to solve the problem that time-dependent reliability is difficult to solve, this manuscript proposes a method for solving time-dependent reliability of bridges using neural networks, which is suitable for existing time-dependent reliability models. Then, compared with the results of Monte Carlo method, the results show that the neural network used in this paper is accurate. At the same time, it can also significantly improve the computational efficiency and has significant advantages compared with the existing calculation methods.

关键词： Dual neural networks Time-dependent reliability Numerical integration direct integration method

来源：评论

学校读者我要写书评

暂无评论

Elastic Equilibrium of a Hollow Cylinder of Finite Length Under Axisymmetric Force Loading

引用

Journal of Mathematical Sciences (United States) 2024年第5期278卷 807-841页

作者： Yuzvyak, M. Yo. Tokovyy, Yu. V. Pidstryhach Institute for Applied Problems in Mechanics and Mathematics National Academy of Sciences of Ukraine Lviv Ukraine

We develop a method for solving axisymmetric problems of the theory of elasticity for a hollow cylinder of finite length subjected to force loading of the end faces and also of the inner and outer cylindrical surfaces. As a result of the direct integration of equilibrium equations, we formulate auxiliary problems for the evaluation of components of the stress tensor via a single function, which is called the Vihak function. By using the obtained expressions, the continuity equations are reduced to a governing equation for the determining function and the system of original boundary conditions is equivalently replaced by integral conditions. We construct the complete systems of eigenfunctions and associated functions with an aim to represent the solution of the problem in the form of superposition of the elementary and self-balanced components. We develop a method for solving the governing equation with the corresponding integral conditions for each component. To determine the self-balanced solution, we develop a recurrent algorithm, which guarantees the possibility of complete separation of variables in the governing equation. The solution thus constructed enables us to perform the exact analysis of stresses in elastic cylinders with different ratios of the generatrix length to the radius. © Springer Nature Switzerland AG 2024.

关键词： analytic solution axisymmetric problem direct integration method hollow cylinder of finite length Vihak function

来源：评论

学校读者我要写书评

暂无评论

A direct-integration-based structural reliability analysis method using non-probabilistic convex model

引用

JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY 2018年第11期32卷 5063-5068页

作者： Nie, Xiao-Bo Li, Hai-Bin Inner Mongolia Univ Technol Coll Sci Hohhot 010051 Inner Mongolia Peoples R China

In practical structural reliability analysis, there is not only random uncertainty but also fuzzy uncertainty. Aiming at the fuzzy reliability of structure, a novel fuzzy reliability method is proposed based on direct integration method and ellipsoidal convex model. Firstly, the decomposition of fuzzy mathematics principle is used to convert fuzzy reliability model into non-probabilistic reliability model, in which fuzzy variables are converted into interval variables. The upper and lower bounds of interval variables are determined by the possibility distribution function on the membership value. Secondly, multidimensional ellipsoid convex models are constructed to quantify the uncertainty because of the complexity of non-probabilistic reliability. Finally, sigmoid function with adjustable parameter is introduced to direct integration method for approximating the step function, and then direct integration method is used to solve the fuzzy reliability. Numerical examples are investigated to demonstrate the effectiveness of the present method, which provides a feasible way for the structural fuzzy reliability analysis.

关键词： Fuzzy variable Ellipsoid convex Interval variable Sigmoid function direct integration method

来源：评论

学校读者我要写书评

暂无评论

Thermal stresses in an elastic parallelepiped

引用

JOURNAL OF THERMAL STRESSES 2022年第12期45卷 1009-1028页

作者： Yuzvyak, Mykola Tokovyy, Yuriy Natl Acad Sci Ukraine Pidstryhach Inst Appl Problems Mech & Math Dept Solid Mech 3-B Naukova St UA-79060 Lvov Ukraine

A semi-analytical algorithm is presented for solving a three-dimensional thermoelasticity problem for a parallelepiped with free edges. By implementing the direct integration method, the problem is reduced to the determination of three Vihak key functions introduced as the integrals of the equilibrium equations. The governing equations for the Vihak functions are derived based on the compatibility equations in terms of stresses. Based on original boundary conditions, the integral conditions are derived for the Vihak functions verbalizing their resultant "force" and "momentum." An approach for separating variables in the governing equations and integral conditions is suggested by implementing special sets of the associated- and eigenfunctions. Numerical case studies are discussed with special attention given to the effect of the Poisson ratio.

关键词： Analytical solution direct integration method elastic parallelepiped exact analysis thermoelasticity

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：