| Created: 5/21/95 |
Updated: 4/18/97 |
PWB In-plane Motion Under Vibration Loading
Objectives
The current vibration analysis programs in the
CALCE software need to be extended so as to
be able to display the in-plane motion of a
PWB subjected to vibratory loading.
Background
Vibration induced wear is a concern with PWB
card edge connectors that are generally designed
to withstand the wear associated with relatively
few insertion/extraction cycles, e.g. < 100, but
not the large number of cycles that could occur
as a result of vibratory motion. There are two
types of in-plane vibratory motion that can
cause connector wear: motion due to rigid body
translations and in-plane motion due to resonant
out-of-plane deformation of the PWB. This
project is only concerned with the resonant
deformation of the PWB.
Approach
The CALCE vibration finite element programs
are optimized to determine the first three mode
shapes of a PWB and then calculate the
dynamic response of the PWB under a
prescribed acceleration loading. The program
cannot directly determine the PWB in-plane
motions due to some of the simplifying
assumptions of code, but by using the calculated
out-of-plane response of the PWB the in-plane
motion can be estimated.
Work Accomplished
An algorithm for estimating the in-plane
response of the PWB under vibratory loading
has been developed. The algorithm uses the
calculated out-of-plane response from the
existing finite element program. Contours maps
of in-plane displacement can be displayed for
the various mode shapes. One limitation of the
current software is the assumption that there is
no in-plane motion at any imposed boundary
condition, i.e. at any imposed edge condition as
well as at any interior point condition.
