Effect of laminate construction on residual stresses in graphite/polyimide composites - The effects of ply-stacking sequence and ply orientation on the magnitude of residual stresses were investigated experimentally in graphite/polyimide angle-ply laminates using embedded-strain-gage techniques

I. M. Daniel*, T. Liber

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

The influence of ply-stacking sequence and ply orientation on the magnitude of lamination residual stresses in graphite/polyimide angle-ply laminates was investigated. The effect of stacking sequence was investigated with laminates of [02/±45]s, [±45/02]s, [0/+45/0/-45]s and [+45/02/-45]s layup. The effect of ply orientation was evaluated with additional specimens of [02/±15]s and [02/902]s layup. Thermal strains were measured using embedded-gage techniques. Residual strains were determined by comparing thermal strains in the angle-ply laminates with those of a unidirectional laminate. The ply-stacking sequence did not have an influence on the magnitude of residual strains. The highest residual strains occur in the [02/902]s laminate and the lowest, approximately one-fourth in magnitude, occur in the [02/±15]s laminate. The maximum residual strains in the [02/±45]s group are slightly lower than those in the [02/902]s laminate. Residual stress computations show that, at room temperature, the transverse-to-the-fibers stresses in all plies, except those of the [02/±15]s laminate, exceed the transverse tensile strength of the unidirectional material.

Original languageEnglish (US)
Pages (from-to)21-25
Number of pages5
JournalExperimental Mechanics
Volume17
Issue number1
DOIs
StatePublished - Jan 1 1977

ASJC Scopus subject areas

  • Mechanics of Materials
  • Computational Mechanics

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