Discrete Damage Modelling of Clamped Tapered Beam Specimen Under Fatigue Loading
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Date
2018Author
Adluru, Hari K.
Iarve, Endel V.
Hoos, Kevin H.
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**Please note that the full text is embargoed** ABSTRACT: Clamped Tapered Beam (CTB) sub-element, proposed by Advanced Composite
Project Team at the NASA Langley Research Center was studied under monotonic
fatigue loading. The specimen was designed to study matrix crack initiation from
pristine condition, delamination initiation and propagation including migration from
one interface to other. Regularized eXtended Finite Element Method (Rx-FEM),
which allows modeling displacement discontinuities associated with matrix cracks
independent of the mesh orientation was used for analysis. Previously developed
fatigue Cohesive Zone Method (CZM) was modified to include the S-N information
in the Newton-Rapson equilibrium loop. The analysis was conducted in two phases,
before and after the experimental data was revealed. The blind predictions were
conducted at R=0.1 load ratio for 80% and 70% values of the fatigue load
amplitude with respect to static strength and overestimated the rate of delamination
growth. The corrected predictions took into account the R=0.2 load ratio, thermal
residual stresses and were based on the modified algorithm. The failure event
sequence and the respective cycle counts were consistent with experimental data.