Strength and Response of Composite Plates Containing an Open Hole and Subjected to Compressive Loading

In this work the effectiveness of stepped repairs to damaged fiber reinforced composite materials is investigated by using previously validated numerical models which were compared with tested repaired composite plates. Parametric studies were carried out in order to assess the scarf ratio (i.e., step length to ply thickness ratio) influence on ultimate forces, displacements, stresses and stiffnesses. FE models with repair scarf ratios varying from the value of 20 to the value 60 with a step increase of 10 were developed. The numerical models allowed a direct comparison of the influence that the scarf ratio had to the strength and stiffness restoration of the repaired composite structure. The study verifies that the restoration of the strength of a damaged laminate depends largely on the size of the repair patch. Generally, the bigger the size of a patch, the stronger the repaired structure is, up to a critical threshold size. To maximize the strength restoration, it is advised that the number of steps in each patch are no less than the number of plies on the base laminate.

Download Full-text

Progressive failure analysis of fiber-reinforced laminated composites containing a hole

International Journal of Damage Mechanics ◽

10.1177/1056789517715088 ◽

2017 ◽

Vol 27 (7) ◽

pp. 963-978 ◽

Cited By ~ 9

Author(s):

Hadi Bakhshan ◽

Ali Afrouzian ◽

Hamed Ahmadi ◽

Mehrnoosh Taghavimehr

Keyword(s):

Failure Analysis ◽

Failure Modes ◽

Progressive Failure ◽

Composite Plates ◽

Failure Criteria ◽

Element Analysis ◽

Progressive Failure Analysis ◽

Numerical Predictions ◽

Open Hole ◽

Failure Loads

The present work aims to obtain failure loads for open-hole unidirectional composite plates under tensile loading. For this purpose, a user-defined material model in the finite element analysis package, ABAQUS, was developed to predict the failure load of the open-hole composite laminates using progressive failure analysis. Hashin and modified Yamanda-Sun’s failure criteria with complete and Camanho’s material degradation model are studied. In order to achieve the most accurate predictions, the influence of failure criteria and property degradation rules are investigated and failure loads and failure modes of the composites are compared with the same experimental test results from literature. A good agreement between experimental results and numerical predictions was observed.

Download Full-text

Failure Mechanisms of Composite Plates With a Circular Hole Under Remote Biaxial Planar Compressive Loads

Journal of Engineering Materials and Technology ◽

10.1115/1.2805974 ◽

1997 ◽

Vol 119 (1) ◽

pp. 56-64 ◽

Cited By ~ 11

Author(s):

A. R. Khamseh ◽

A. M. Waas

Keyword(s):

Failure Mechanisms ◽

Compressive Loading ◽

Infinite Plate ◽

Laminated Composite ◽

Composite Plates ◽

Laminated Composite Plates ◽

Biaxial Tests ◽

Compressive Loads ◽

Stress Raisers ◽

Plate Width

We report the results of an experimental investigation carried out for the analysis of failure mechanisms in fibrous laminated composite plates containing stress raisers, in the form of circular cutouts, under static biaxial planar compressive loading (i.e., compression in the two inplane orthogonal directions). A series of biaxial tests were carried out with 48 ply graphite/epoxy composites of varying fiber orientation. In all cases, the hole diameter to plate width aspect ratio remained in a range suitable for infinite plate assumptions. Fiber microbuckling, fiber kink banding, and fiber/matrix debonding are identified as the dominant failure mechanisms.

Download Full-text