摘要:

AbstractA new finite element procedure for calculating stress intensity factors in elastic crack problems is developed. In common with a number of other approaches in the literature, the procedure combines the analytical singular fields present in a problem with a finite element treatment of the residual regular problem. What distinguishes the procedure is the use of path‐independent integrals to balance the analytical and numerical contributions. A set of test problems with exact solutions is analysed and demonstrates that the procedure is readily implemented and can accurately evaluate stress intensity factors with a modest amount of computational effort. The application of two competing methods to the test problems further demonstrates that the new procedure is markedly superior in both its initial accuracy and its rate of convergence. The paper concludes with two additional illustrations of the procedure as applied to the single‐edge crack and the centre crack; these also yield accurate results for little computational eff

ISSN:0029-5981    

DOI:10.1002/nme.1620181102

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA closed solution for dynamic problems with the transform technique is possible for linear behaviour only. Therefore, a strategy for the solution involving nonlinear material behaviour has been developed. Herewith, an iterative equalization is made possible by the repeated transform of the differential equations given through the initial strain method.

ISSN:0029-5981    

DOI:10.1002/nme.1620181103

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThird‐ and fourth‐order accurate Nørsett rational approximations to the exponential and associated semi‐implicit Runge–Kutta methods are used for the construction of efficient, accurate and unconditionally stable schemes for the direct numerical integration of the linear, nonhomogeneous, second‐order equations of structura

ISSN:0029-5981    

DOI:10.1002/nme.1620181104

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA frontal solution program is presented, based on the original work of Irons, published in 1970. The main drawback of the original frontal solution program that the complete front matrix has to reside in core has been overcome by ‘partitioning’ the front matrix. The programming strategy has been optimized to (a) minimize the number of I/O operations on the partitioned front‐matrix (b) optimize the speed of I/O transfer between high speed memory and slow peripheral (or secondary) storage media, and (c) make the program transportable and easily implementable on different types of computers, including mini‐ and micro‐

ISSN:0029-5981    

DOI:10.1002/nme.1620181105

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA review of 4‐node, 12 degrees‐of‐freedom quadrilateral elements for thin plates is presented. A new element called DKQ is discussed. The formulation is based on a generalization of the efficient and reliable triangular element DKT presented in References 1 and 2 and on the rectangular element QC presented in Reference 3. These elements are derived using the so‐called discrete Krichhoff technique. A detailed numerical evaluation of the behaviour of the DKQ element for the computation of displacements and stresses for thin plate bending problems is presented and discussed. The DKQ element appears to be a simple and reliable 12 degrees‐of‐freedom thin plate bend

ISSN:0029-5981    

DOI:10.1002/nme.1620181106

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620181107

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620181108

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractDependence of dynamic response of nonlinear mechanical systems on design variables is analysed. An adjoint variable method is used to derive first‐ and second‐order derivatives of measures of dynamic response with respect to design variables. A computational algorithm is presented for numerical calculation of first and second design derivatives. A simple oscillator example is solved analytically and by the adjoint variable method, with identical results. A burst fire automatic weapon mechanism with linear and nonlinear damping is treated numerically. It is shown that quadratic appriximations of dynamic response, using results of second‐order design sensitivity analysis, can be substantially better than conventional linear approxima

ISSN:0029-5981    

DOI:10.1002/nme.1620181109

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractA two‐dimensional linear elastodynamic analysis of crack initiation, fast crack propagation and crack arrest in the DCB specimen is presented. The analysis is performed using the previously developedSMF2Dcode in its generation mode. The experimentally measured crack tip motion, as well as the specimen's geometry and its material characteristics, serve as input to the simulation. The dynamic stress intensity factor, the dynamic energy release rate and the various distributions of energies are subsequently evaluated. The numerical results are found to be in very good agreement with analytical and experimental finding

ISSN:0029-5981    

DOI:10.1002/nme.1620181110

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY

摘要:

AbstractThe solution of a fourth order differential equation, which governs a number of problems in structural mechanics and possibly elsewhere, is considered. It is shown how the use of complex arithmetic can be avoided in the computation.

ISSN:0029-5981    

DOI:10.1002/nme.1620181111

出版商:John Wiley&Sons, Ltd    

年代:1982

数据来源: WILEY