A new merit function for evaluating the flaw tolerance of composite laminates.

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National Aeronautics and Space Administration, Langley Research Center, National Technical Information Service, distributor , Hampton, Va, [Springfield, Va
Graphite-epoxy composites., Failure analysis., Stress concentration., Cr
Other titlesArbitrary size holes and center cracks
StatementMartin M. Mikulas, Jr. and Rod Sumpter.
SeriesNASA contractor report -- NASA CR-202577
ContributionsSumpter, Rod., Langley Research Center.
The Physical Object
FormatMicroform
Pagination1 v.
ID Numbers
Open LibraryOL17124488M

In a previous paper [1], a new merit function was determined to examine the flaw tolerance of composite laminates. In brief summary, it was determined that the strength performance of a uniaxially loaded infinite width orthotropic sheet could be optimized by maximizing the new merit function, vEx.

Details A new merit function for evaluating the flaw tolerance of composite laminates. FB2

In this function, Ex. In a previous paper [ 1], a new merit function was determined to examine the flaw tolerance of composite laminates. In brief summary, it was determined that the strength performance of a uniaxially loaded infinite width orthotropic sheet could be optimized by maximizing the new merit function, _E x.

In this function, Ex. Get this from a library. A new merit function for evaluating the flaw tolerance of composite laminates. [Martin M Mikulas; Rod Sumpter; Langley Research Center.].

In this paper, the merit function is expanded to include the flaw cases of an arbitrary size circular hole or center crack. Failure prediction for these cases is determined using the point stress.

In a previous paper, a new merit function for determining the strength performance of flawed composite laminates was presented. This previous analysis was restricted to circular hole flaws that were large enough that failure could be predicted using the laminate stress concentration : Rod Sumpter and Jr.

Martin M. Mikulas. In the present paper a new and simple merit function is proposed for maximizing the strength performance of flawed composite laminate for different design requirement.

This new merit function takes into account the flaw tolerance of a composite laminated as well as its : Rod Sumpter and Jr. Martin M. Mikulas. In the present paper a new and simple merit function is proposed for maximizing the strength performance of flawed composite laminates for different design requirements.

This new merit function takes into account the flaw tolerance of a composite laminate as well as its stiffness. A new merit function for evaluating the flaw tolerance of composite laminates.

Part II, Arbitrary size h A new merit function for evaluating the flaw tolerance of composite laminates. Part II, Arbitrary size h Characterization of mode I and mixed-mode failure of adhesive bonds between composite adherends [microfo. Different laminates are used to investigate the crack branching problem through the ply angles of a quasi-isotropic laminate.

Delamination flaws and ply gaps are studied, and a new type of flaw that combines a ply gap with a pre-crack is introduced and by: 6. Add tags for "A new merit function for evaluating the flaw tolerance of composite laminates. Part II, Arbitrary size holes and center cracks". Part II, Arbitrary size holes and center cracks".

Be the first. The manufacturing process and service of the composite laminates frequently lead to delamination. Vibration analysis is an integral part of most engineering structures. In the present article we provide a relevant survey on the various analytical models and numerical analyses for.

Introduction. In the last years, the use of composite materials as a primary structural element has increased. Some new aircraft designs, such as Airbus A and Boeing use composite materials even for primary structural elements (e.g.

wing spars and fuselage skins), achieving lighter structures without loss of by: A new damage model for composite laminates. and potentialities as a damage tolerance technique. and damaged composite plates in order to evaluate different types of metrics for damage.

“Damage Tolerance” is unique to each industry Aircraft have most stringent composite laminates will probably not need this high level, and you probably cannot afford it (unless you are building an aircraft) For some programs the philosophy is “make sure it doesn't get hit” 12Cited by: 2.

Modeling delamination in composite laminates using XFEM by new orthotropic enrichment functions. In this research, the extended finite element method (XFEM) is improved for modeling interfacial cracks between two orthotropic media by new set of orthotropic enrichment functions.

One regular ply can be replaced two or more thin plies. For example, with two thin plies and two angles, one bi-axial ply can be [±35]. Such bi-axial ply is available from Chomarat for many enclosed angles.

Then instead of sub-laminates in 6 to 10 plies, they can have them in 1, 2, or 3 plies. In this paper a new concept on z-pinning technology named by authors as 'z-pinning patch' will be introduced, which advantage is easy application at manufacturing site of composite structures.

considering composite laminates in industrial applications. Thus, the design of composite laminates may be formulated as a multiobjective optimization problem. The objectives might be, e.g. the mass of the structure ρA or the total elastic strain energy U, i.e.

the work done in deforming a. Free vibration analysis of multi-layered composite laminates based on an accurate higher-order theory among researchers, there is a growing appreciation of the importance of developing new kinematics for the evolution of accurate two-dimensional theories for the analysis of thick laminates with high orthotropic ratio, leading to less Cited by: A.

Farrokhabadi, B. Mohammadi, H. Hosseini-ToudeshkyA generalized plane-strain crack density-based model for evaluating the finite fracture toughness of composite laminates Mech Adv Mater Struct, 24 (), pp./Cited by: 8. Finite element analysis and experimental evaluation of bonded, riveted and hybrid joints in glass fibre epoxy composite laminates for aircraft structure C Experimental evaluation and finite element analysis of composite leaf spring for automotive vehicle.

By means of computation and analysis of damage tolerance of composite laminates with hole or crack, the conclusion is brought forth that crack on laminates can’t be cut into hole to improve the residual strength; otherwise the damage will become more serious.

The method and conclusion can be reference and basis for battle damage repair of airplane composite : Wu Wen Yao, Ping Zhou, Sheng Li Hou, Ming Wu Tu.

Weight minimization of composite structures necessarily in-volves strength constraints, because decreasing number of load carrying plies eventually leads to failure. The structure must be able to withstand the imposed loads without suffering any failure. In this study, only the static failure modes are assumed to be crit-ical for the laminates.

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Lamination is the technique/process of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance, or other properties from the use of the differing materials, such as plastic.A laminate is a permanently assembled object created using heat, pressure, welding, or gluing.

Composite laminates. Assemblages of layers of fibrous composite materials (see illustration) which can be tailored to provide a wide range of engineering properties, including inplane stiffness, bending stiffness, strength, and coefficients of thermal expansion.

D x = 10 9 N m 2, D y = 10 9 N m 2, D xy = 10 9 N m er with the assumption that v x v y is the same as v 2 of the quasiisotropic plate (v 2 = ) and equations (12) to (17) the material properties are determined as.

E x = 10 9 N m 2, E y = 10 9 N m 2, G xy = 10 9 N m 2, v x =v y = It is obvious that the parameters describe an orthotropic. INTRODUCTION. In aircraft maintenance programme it is important to inspect the mechanical damage and assess the extent of the repair work.

But in schedule maintenance it is a difficult to finding the defects rapidly, as the maintenance of aircraft must be accomplished within scheduled time and same to be released in time for commercial operation.

Composite materials are increasingly used in aerospace, underwater, and automotive structures.

Description A new merit function for evaluating the flaw tolerance of composite laminates. EPUB

They provide unique advantages over their metallic counterparts, but also create complex challenges to analysts and designers.

Practical Analysis of Composite Laminates. where k is a constant. The Weibull modulus, m, is then determined graphically as the slope of the “Weibull plot” of ln[ln(1/1−P)] against a set of fracture data, the samples are ranked from weakest to strongest, and the probability of fracture, P, is most accurately estimated as P i =(i−)/n, where P i is the rank of the ith specimen and n is the number of specimens tested.

Thoroughly covering the extensive and rapid development of the field of composite laminates over the last twenty years, the major portion of this work consists of new contributions. Where still applicable, some parts of an earlier book on the subject have been incorporated in the text.

They provide unique advantages over their metallic counterparts, but also create complex challenges to analysts and designers. Practical Analysis of Composite Laminates presents a summary of the equations governing composite laminates and provides practical methods for analyzing most common types of composite structural by: LAMINATED COMPOSITE PLATES David Roylance Department of Materials Science and Engineering Massachusetts Institute of Technology Cambridge, MA File Size: KB.An experimental investigation of penetration failure modes in composite laminates The absorbed kinetic energy, Ea, the impact and the residual kinetic energies are linked by the equation, as22 2 E =−mv mvr (1) For the target, when the shape and material of the projectile are unchanged the ballistic limit velocity is a constant.