The use of Taylor polynomials as shape functions in a Rayleigh-Ritz discret
ization of flexible beams in dynamic multi-body systems has been previously
investigated (1,2). This approach is relatively simple, but it was found t
o cause some ill-conditioning problems in the numerical solution of the sys
tem equations. In this paper, two solutions to these problems are presented
. First, better-behaved system equations can be obtained by using orthogona
l Chebyshev or Legendre polynomials in place of Taylor polynomials. Secondl
y, a judicious choice of numerical solver can reduce or eliminate the ill-c
onditioning problems. Two examples are used to demonstrate these findings.