...JR Reeder The mixed-mode bending (MMB) test for delamination toughness was first introduced in 1988. This simple test is a combination of the standard Mode I (opening) test and a Model II (sliding) test. This MMB test has become widely used in the United States and around the world for mixed-mode...

... configurations; however, GII remained nonzero over the range of debond lengths considered. KEYWORDS: stitching, delamination, debonding, skin-stiffened structure, finite element analysis Introduction Stitched warp-knit textile composite materials are currently being considered for use in primary aircraft...

...J Li Three-dimensional finite element modeling was used to analyze the delamination between the stiffener flange and the skin of a typical pull-off specimen representing a section of a stiffened skin panel. The finite element analysis results were used to calculate the total strain energy release...

... repair lap joint. The results show that the proposed approach can be used to predict critical failure modes, damage initiation loads and locations, crack and/or delamination stability, static strength, residual strength, and fatigue life. Discussion is also included on how this approach can be applied...

...I Paris; R Bennett; M Mager; A Poursartip This paper presents a technique for measuring the crack opening displacement (COD) and crack shear displacement (CSD) profiles at a delamination crack tip, and using them to evaluate the effective ‘local’ Mode I and Mode II strain energy release rates...

... of a combination of bending, shearing, micromachining, and erosion. The micromechanisms associated with AWJ hole drilling, or piercing on the other hand, are microfracture of fibers and matrix, delamination, and fragmentation of fiber bundles. The tensile mechanical behavior is negligibly different between the AWJ...

...LE Asp; A Sjögren; ES Greenhalgh This paper presents a study on delamination growth in Mode I, Mode II and mixed mode under fatigue loading in an HTA/6376C composite. The computed slopes of the modified Paris plots were high. Therefore, threshold values of the strain energy release rate...

... fiber reinforced plastic (GFRP) laminates when the hole is subjected to bearing load. In the first part, the influence of drilling parameters on the type and extension of the damage is analyzed. The damage is described at the macro level (delaminated area) and at the micro level (cracks, fiber-matrix...

...-of-plane damage and delamination at ply interfaces. The damage most often occurs between hybrid plys and dominates the lifetime response of a thick-section FRP structure. In this paper a model is developed to address these issues. The methodology employs the quadratic delamination initiation failure...

..., there is a concern about the reliable performance of the FRP-wood adhesive bond, which is susceptible to delamination. The overall objective of this two-part paper is to develop a qualification program to evaluate the service performance and fracture of composite/wood bonded interfaces. Two types of FRP-wood...

... fracture of hybrid interfaces, and the fracture toughness data obtained can be used to predict whether or not a bonded interface will delaminate under general service conditions. Based on the results of this two-part study, recommendations and guidelines are given for evaluation and qualification of FRP...

... failure for all other layups was predicted using a numerical model that accounted for both constraint and size. Tensile strength was predicted using a strain energy release rate model for delamination of surface angle plies. A delamination energy value for each ply angle was calculated from the thinnest...

...-after-impact response, increase fracture toughness, and severely restrict the size and growth of delamination. These improvements have been documented repeatedly in the literature, and it is generally accepted that TLR restricts the size and growth of delamination. In this paper we report a detailed...

.... Compression after impact (CAI) strengths were measured, and the damage tolerances of hybrid tubes were assessed by the residual strengths. Compared to compressive strengths of the tubes without low-energy impact, CAI strengths of hybrid tubes decreased significantly due to delamination generation...

...A Pieracci; BD Davidson; V Sundararaman Energy release rates obtained by geometrically linear and geometrically nonlinear finite element analyses of homogeneous, symmetrically delaminated single leg bending specimens are presented for a variety of materials, specimen geometries and fixture...

... consists of a [ 90 ∕ ( ± 45 ) 3 ∕ ( ∓ 45 ) 3 ∕ 90 ] s laminate with a delamination introduced by a non-adhesive film at the mid-plane along one edge and loaded in a special fixture to create torsion along the length of the laminate. Dye penetrant enhanced X-radiograph of failed specimens revealed...

...RH Martin The test methods to determine interlaminar fracture toughness of composite materials require values to be determined at delamination initiation from the thin insert. In woven composites, the location of the insert relative to the yarns will vary which may effect the toughness values...

... of unnotched and notched laminates. The model predictions were in good agreement to experimental results for several different fatigue loading histories and several different laminate stacking sequences. composites graphite/epoxy damage matrix cracks delamination internal state variables...

...S Subramanian; WS Chan In this study, the effect of loading frequency on delamination onset and growth characteristics of (30/−30 2 /30/90) s IM6/3501-6 laminates, with and without an interleaf was studied. FM 300 adhesive layers, manufactured by American Cynamid, were placed at the 30/90 interface...

... to originate at the point of contact between the impacting tup and the specimen. KEYWORDS: composite material, filament-wound composite, impact, damage, delamination, matrix cracking, fiber fracture, X-ray radiography During the last ten years, the use of advanced composites, especially continuous fiber...