摘要:

Abstract:Artificial neural networks can provide improved computational efficiency relative to existing methods when an algorithmic description of functional relationships is either totally unavailable or is complex in nature. For complex calculations, significant reductions in elapsed computation time are possible. The primary goal of this project is to demonstrate the applicability of artificial neural networks to composite material characterization. As a test case, a neural network has been trained to accurately predict composite hygral, thermal, and mechanical properties when provided with basic information concerning the environment, constituent materials, and component ratios used in the creation of the composite. A brief introduction to neural networks is provided along with a description of the software tools and interfaces used in the project. Finally, the project results are presented.

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00179.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:In this paper, the constitutive models involving two active intersecting yield surfaces, such as Lade's model, are considered and a new integration algorithm is formulated. The formulation introduces a new class of the return mapping algorithm within the framework of the operator splitting methodology. The proposed algorithm is applicable to a general class of elastoplastic constitutive models exhibiting associative or nonassociative flow rule, arbitrary yield criteria and hardening laws. The algorithm can handle one or two active yield surfaces at a time. The development leads to a relatively simple, straightforward algorithm for updating the stresses at Gauss point.Finally, the new algorithm is implemented in a generalized nonlinear finite element computer program incorporating Lade's model. The results of a number of boundary value problems are presented and compared with available experimental data and theoretical formulas. The comparisons indicate that incorporating the new class of return mapping algorithm gives reasonable solutions.

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00180.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:A generally applicable mathematical model, tailored for use on a Personal Computer, as the design tool to simulate unsteady flood flow in a network of interconnected rivers has been developed and applied to the Sham Chun River along the border between Hong Kong and the People's Republic of China. The effect on the improved Sham Chun River due to the proposed river training in the River Indus, one of its tributaries, is evaluated. The one‐dimensional unsteady flow model itself is broadly applicable to a wide range of hydrologic conditions and varying field situations. It incorporates real hydraulic features including branched channels and ‘tidal flats’ flooding and drying. The time history of water stages and discharges are computed at any desired location throughout the connected essentially one‐dimensional channel network subject to initial and boundary conditions. Details are given of techniques adapted in using the computational scheme to quantify the unsteady flow condition and the means to assure an efficient numerical solution as well as to verify the accuracy of the computed outputs by subjection to carefully selected schematic simplified test cases and real prototype cases with numerical solution method is a useful predictive engineering tool in river

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00181.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:A generally applicable mathematical model, tailored for use on a Personal Computer, as the design tool to simulate unsteady flood flow in a network of interconnected rivers has been developed and applied to the Sham Chun River along the border between Hong Kong and the People's Republic of China. The effect on the improved Sham Chun River due to the proposed river training in the River Indus, one of its tributaries, is evaluated. The one‐dimensional unsteady flow model itself is broadly applicable to a wide range of hydrologic conditions and varying field situations. It incorporates real hydraulic features including branched channels and ‘tidal flats’ flooding and drying. The time history of water stages and discharges are computed at any desired location throughout the connected essentially one‐dimensional channel network subject to initial and boundary conditions. Details are given of techniques adapted in using the computational scheme to quantify the unsteady flow condition and the means to assure an efficient numerical solution as well as to verify the accuracy of the computed outputs by subjection to carefully selected schematic simplified test cases and real prototype cases with numerical solution method is a useful predictive engineering tool in river

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00182.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:A new microcomputer program for one dimensional site response analysis, which is based on the accurate direct step‐by‐step integration of the nonlinear equations of motion, is presented. The soil material properties are represented by a Ramberg‐Osgood hysteresis model in which the loading and unloading follow different nathas Therefare realistic soil properties can be incorporated in the analysis. The accuracy of the numerical methods and the computer program is demonstrated by analysis of a site in downtown Mexico City. The results compare favorably with the motions recorded during the 1985 Mexico City earth

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00183.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:This paper addresses the need to improve the flexibility, productivity and effectiveness of educational methods, especially in teaching subjects invoving largescale phenomena that do not lend themselves well to lectures or laboratory experiments. The central part presents a multimedia educational system for teching construction equipment and methods. It describes the main objectives in developing this system, and illustrates its upproach with one ofn the prototype modules that deals with earthmoving scrapers. The educational results are mentined, along with suggestions for cooperation among universities to make more systems of this type widely available. The description of the development methodology also coments on its limitations, but these are rapidly being overcome with improved standards and availability of similar tools on other computers.

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00184.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract:Flood routing is one of the very important basic topics that is dealt with in the first course in hydrology. To illustrate the solution of the Muskingum method requires the computation of K and X, Which are usually obtained using the graphical approach. Similarly, reservoir routing requires a storage function, and a semigraphical approach is adopted. The hydraulic method of routing of flood requirs a knowledge of the soulution of nonlinear hyperbolic partial differential equations. In this paper, spreadsheet of LOTS 1–2‐3 has been used to demonstrate its potential as a pedagogical tool for solving flood routing problems for both the hydrological and hydraulic approac

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00185.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00186.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:1093-9687    

DOI:10.1111/j.1467-8667.1991.tb00187.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY