| 摘 要： | This paper derives the Ritz method and Trefftz method in li-near elastomechanis with the help of general mathematicalexpressions.Thus it is proved that Ritz method gives theupper bound of the corresponding functional extremum,whileTrefftz method gives its lower bound.At the same time ithas been found that the eigenvalue problem(e.g.the naturalfrequency problem)concerning the functional variational me-thod in Trefftz method is in concord with the lower boundmethod of the loosened boundary condition which seeks forthe eigenvalue.of course,the results of this derivationare also applicable to the sort of functional variationalmethod of which Euler’s equation is linear positive defi-nite.
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