Dynamic failure prediction of cross-rolled beryllium sheets subjected to vibration loads /

(4.5 x 0.4 in.) to 114.3 x 114.3 mm (4.5 x 4.5 in.). AU

Bibliographic Details
Main Author: Serna, Oscar R., 1967-
Format: Thesis eBook
Language:English
Published: [Place of publication not identified] : [publisher not identified] ; 1996.
Subjects:
Online Access:Link to OAKTrust copy
Description
Summary:(4.5 x 0.4 in.) to 114.3 x 114.3 mm (4.5 x 4.5 in.). AU
(80,000 psi) were obtained from the beryllium plate
acceleration level required to fail the specimen at
actual failure stress.
amplitude is increased from zero to a target maximum within a
and verify a numerical method for prediction of failure for
are predicted to within an average of seven percent of the
aretested to failure. Energy is imparted to each plate in
at NASA Johnson Space Center. As a precursor to experiments
attached to the plate and a point on the excitation fixture,
beryllium SR200 sheet material are incorporated into a
clamped by a specially designed fixture at the center of the
commercial finite element code by means of a specially
continuously increased until the specimen fails; the
cross-rolled beryllium sheet structures that are subjected to
decrease its natural frequency, and thereby reduce the
experiments and numerical simulations are carried out on
experiments. These stresses compare well with stresses
failure envelope is made at each incremental load. Failure
failure models for regular annealed glass and cross-rolled
failure models, the primary failure stresses for each plate
Frequencies of excitation ranged from 71 Hz to 96 Hz. Tsai-Wu
glass and beryllium plates. A-total of five glass and
glass plates, 2.54-mm (0.1-in.) thick beryllium specimens
glass specimens were approximately 2.24 nun (0.088 in.) in
is predicted to occur when the state of stress at one or more
is used to obtain time-history data from transducers attached
length to form a double cantilever. Effective length and
mm (4.5 x 1.0 in.) to 114.3 x 114.3 mm (4.5 x 4.5 in.).
model. A comparison between stress at a point and the
nine beryllium specimens with various length-to-width ratios
obtained by other investigators using static loads. By
of three in-plane components of stress is compared with the
period of 15 seconds. A high-speed data acquisition system
points in the material exceeds those stresses that satisfy
resonance. Three sets of specimens (each set consisting of
respectively. Laboratory tests were conducted at the
Specimen length and width dimensions vary from I 1 4.3 x 25.4
specimens is brittle. Numerical models show good agreement
specimens were also tested to gain additional information.
steel mass was added to the end of each plate in order to
stress level at each integration point in the finite element
support. Tensile failure stresses of approximately 551,6 Mpa
table. Amplitude of excitation at the resonant frequency is
the failure criterion. Because each specimen was excited at
the first fundamental mode, maximum stresses occurred at the
the form of sinusoidal base excitationby means of a shaker
the laboratory and numerically simulated. These plates were
The principal objective of this investigation is to develop
thickness. In contrast to the structural symmetry of the
three equal size plates) were excited to failure. Two other
to each specimen. Strain gages and an accelerometer are
vibration loads. To this end, complementary laboratory
Vibrations and Control Laboratory of Texas A&M University and
visual inspection, it is determined that the failure of all
were clamped only at one end to form a single cantilever. A
width dimensions of each specimen vary from 114.3 x 10.0 min
with beryllium, a series of glass specimens were tested in
with experimentally measured quantities. Using the developed
written subroutine. A failure criterion that is a function
Item Description:"Major subject: Civil Engineering".
Vita.
Physical Description:xv, 154 leaves : illustrations ; 28 cm.
Also available online.
Issued also on microfiche from Lange Micrographics.
Bibliography:Includes bibliographical references.