A practical model to predict the time-dependent behaviour of angle-ply laminates from limited creep data

• Type: Article in International Scientific Journal
• Date: 2022

Authors

Rui Miranda Guedes (Author) FEUP

Journal

Title: Mechanics of Time-Dependent Materials

Pages: 1043-1067

ISSN: 1385-2000

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 0 Citations

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Other information

Authenticus ID: P-010-7HR

DOI: 10.1007/s11043-022-09544-1

Abstract (EN): Modelling non-linear behaviour of polymers and polymer fibre-reinforced composites retains significant interest due to its extensive application in primary structures. Simple models are helpful in the design, preferably calibrated from a few short-term mechanical tests. Creep tests are simple to implement, and their duration may depend on the period of interest to analyse. The Norton-Bailey law complies with simplicity and effectiveness when representing the creep response. The time-dependent mechanical response of polymers under arbitrary loading conditions may follow two different theories; time- and strain-hardening. The formal demonstration developed here allowed us to link these two theories to specific time-integration schemes employed in the past. However, both formulations lead to the same expression for the creep-loading condition, which implies the same model parameters in this case. Few research works have applied these theories to polymer-based composites restricted to study the creep-loading condition. Here, a novel approach proposes to model the time-dependent behaviour through the time-hardening and strain-hardening theories with a single viscoplastic element governed by a Norton-Bailey or a Singh-Mitchell law. Experimental data collected from the literature of carbon-reinforced epoxy angle-ply laminates supported the validation process under different loading conditions. The calibration of the model parameters proceeds from creep data at two different stress levels. Thus, time- and strain-hardening theories made predictions for distinct loading conditions, i.e. for multiple creep and creep-recovery cycles, constant strain rate and multi-step stress relaxation. The strain-hardening formulation proved capable of predicting the time-dependent response under different loading conditions from a unique set of model parameters. The current methodology reduces the effort needed to characterise engineering materials when considering the time-dependent behaviour, particularly for polymer-based composites.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 25