摘要:

In double‐porosity and multiple continuum models the fractured rock domain can be simplified as two overlapping continua, one for the matrix block system and the other for the fracture network. In this case, it is necessary to define an exchange term accounting for the transfer of fluid and solute masses between the two continua. A newly derived geometric parameter appears in the fluid exchange term, and is valid for any point‐centered block. The geometric parameter is more general and has a clear physical meaning. It is a function of both the shape and the size of the matrix block and agrees well with the double porosity model. The geometric center and conductance of the element is different under the quasi‐steady state compared to the steady state. Quasi‐steady condition is more suitable than steady state condition for modeling fractured media.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677637

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Several new stability criteria for the linear time‐delay system represented by some simple closed regions in the complex plane are proposed. In these criteria, the system's stability can be easily determined by examining the locations of the eigenvalues of the system matrixA0or its delay matrixAd. In other words, we do not need to solve any complicated characteristic equation of the system.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677638

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The linear defuzzified output of a fuzzy controller with two fuzzy variable inputs and one output is discussed in this paper. Arbitrary amounts of triangular fuzzy numbers are employed to fuzzify the linguistic variables in fuzzy control rules. We show that the defuzzified output is exactly equivalent to a linear function of the inputs to the fuzzy controller by using three mixed fuzzy logic operators to evaluate the control rules.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677639

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A disconnectedness problem which appeared in the 1‐subcycle parallel thinning algorithm [1] is shown and a correct condition is presented to overcome this problem. As a result, to preserve the connectivity of a P8ET‐type thin line, the removal of a (quasi) T‐junction should be guaranteed by its neighbors that do not belong to any one of the commonly used subwindows, mutually opposite subwindows, and T‐junction cases.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677640

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

By simplifying the impact damages as a single delamination near the surface with an elliptical boundary, the approximate solution of total strain energy release rates can be derived as a function of delamination major axis, minor axis, external compressive strain, Possion's ratio of parent medium, extensional and bending stiffnesses of sublaminate. A linear relation of residual strength versus strain energy release rate can be constructed by correlating the approximate solution with test data of compressive residual strain (strength) after impact (CSAI), indicating that the dimension between the delamination major and minor axis should be dependent. In addition, the delamination aspect ratio is found to be not only a function of the specimen geometry and the extensional stiffness, but also a function of laminate thickness. The approximate solution provides a method for predicting the post impacted strength of composite laminate for only either thick laminate or thin laminate with low impact energy.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677641

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A mixed finite element scheme based on assumed local high‐order displacements is proposed for the free vibration of thick laminated plates. The effects of transverse shear deformation, transverse normal stress and rotary inertia are considered in the formulation. Cross‐ply laminates with simple supports and angle‐ply laminates with clamped edges are presented as examples. The three dimensional elasticity solutions of cross‐ply laminates with simple supports are used to assess the accuracy of the present scheme. The effects of the span‐to‐thickness, aspect and material anisotropy ratio on the fundamental natural frequency are investigated. The present results are compared with the results in the published literature, and agree closely with the 3‐D elasticity solutions.

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677642

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0253-3839    

DOI:10.1080/02533839.1994.9677626

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor