Showing papers in "Composite Structures in 1989"

TL;DR: In this article, the influence of specimen geometry on the low velocity impact response of a series of CFRP laminates has been studied, and the subsequent development of damage has been shown to depend strongly upon the energy absorbing capability of the structure, and this has been further highlighted by assessing the geometrical dependence of the perforation threshold.

TL;DR: In this paper, a two-phase computational procedure for the accurate prediction of vibration frequencies, stresses, and deformations in simply supported bidirectional multilayered composite plates is presented.

TL;DR: The impact damage response of new tough carbon fiber composite systems was investigated in this paper, where the low velocity impact damage tolerances of crystalline thermoplastic and toughened epoxy matrix composites were compared and contrasted for two different stacking sequences and target geometries.

TL;DR: In this paper, an elasticity solution for the analysis of a laminated circular cylindrical shell roof with simply-supported edges is presented, and the displacements and stresses of the solution are expressed in terms of infinite series.

TL;DR: In this paper, the Ritz method is used for angle-ply plates, and good convergence is obtained by using 144 terms in the double-sine series for the displacement function, and tabulated results are presented for the first eight non-dimensional frequencies of square and rectangular (a b = 1,2 and 0·5 ) plates made of E-glass/epoxy, boron/epoxide, and graphite-epoxy materials, for different numbers of layers and for varying fiber orientation angles.

TL;DR: A series of low and high velocity impact tests have been undertaken on a number of CFRP laminates in order to assess the influence of the projectile mass upon the impact response and subsequent loadbearing capability of a composite structure.

TL;DR: In this article, a micromechanics analysis is performed for the determination of the five independent elastic moduli of unidirectional fiber composites by considering viscoelastic phases and by using the correspondence principle and the inversion of the Laplace transform.

TL;DR: In this paper, a three-dimensional finite element analysis of pin-loaded and bolted holes in (0/90) s and (90/0) s laminates has been performed and the importance of the clamping ratio, stacking sequence and clamping type are shown to have a fundamental influence on the magnitude of interlaminar normal stress local to the bolt hole.

TL;DR: In this paper, an overview of the structural aspects of the design and development of a local reinforcement designed to lower the stresses in a region of the F-111C wing pivot fitting which is prone to cracking.

TL;DR: In this paper, the authors studied the influence of bending-twisting coupling parameters on the vibration frequency of symmetric angle-ply laminate and found the optimal layup that maximizes the lowest free vibration frequency.

TL;DR: In this article, the authors conducted underwater shock testing of representative composite panels and a full scale hull section and provided an understanding of failure modes for this type of composite under blast loading.

TL;DR: In this article, the thermal postbuckling behavior of composite laminated plates subjected to a non-uniform temperature field is investigated by the finite element method, based on the principle of minimum potential energy, the nonlinear stiffness matrix and geometry matrix are derived.

TL;DR: In this paper, the buckling behavior of orthotropic square plate with or without a central circular hole is analyzed with the aid of the finite element method, and the first buckling mode may be two or three half-waves, depending on the degrees of orthotropy as well as boundary conditions.

TL;DR: In this article, a generalized Levy-type solution in conjunction with the state space concept is developed for the bending, buckling and vibration of antisymmetric angle-ply laminated plates.

TL;DR: In this article, a perturbation approach was used in combination with the orthotropic expressions, and was seen to give very good results with far less computation than in, e.g., finite difference or finite element calculations.

TL;DR: In this paper, a general one-dimensional model of a composite delaminated elongated strip (wide beam) under arbitrary axial and transverse loading and boundary conditions is used for predicting the classical buckling load, with the bending-stretching coupling effect as well as the prebuckling geometrical nonlinearity taken into account.

TL;DR: In this article, the use of thermal emission measurements to determine the surface stresses for a class of problems involving advanced fiber composite materials was examined, experimentally and numerically, for problems associated with repair technology, bonded joints and impact damage.

TL;DR: In this paper, the use of thermal emission measurements as a means of assessing severity of damage and monitoring damage growth in composite materials is examined, experimentally and numerically, and the thermal emission profile reflects the interaction of load, geometry, material and damage in a nondestructive fashion.

TL;DR: In this paper, the accuracy of the classical shell theory in the prediction of buckling loads of laminated shallow shells of revolution loaded by external pressure or axially compressed was analyzed. The shells studied are circular cylinders, barrels, inverse barrels and spherical sections.

TL;DR: In this article, a finite element analysis with inverse formulation is carried out to study the stress distributions, and the results are concisely presented by defining suitable parameters The results show some interesting features The normalised maximum bearing stress on the hole boundary not only varies nonlinearly with the magnitude of the load parameter but the nonlinear law depends on the type of load (push or pull) on the pin.

TL;DR: In this paper, a nonlinear differential equation method (NDEM) is proposed to calculate the in-plane stresses and strains over any time period for a general laminate constructed from nonlinear viscoelastic orthotropic plies.

TL;DR: In this article, the flexural vibrations of triangular composite plates are investigated for the effects of fiber orientation, plate aspect ratio and boundary conditions using a computationally efficient and accurate numerical method.

TL;DR: In this paper, the thermal post-buckling behavior of orthotropic square plates with simply supported edges has been studied using the Rayleigh-Ritz method and the formulation and the solution for the linear buckling temperature and postbuckling temperature are presented in closed form together with a set of numerical results.

TL;DR: In this paper, the state space concept is used to develop Levy-type solutions for anti-symmetric angle-ply laminated plates using the Yang, Norris and Stavsky (YNS) theory.

TL;DR: In this paper, the interference fit pin exhibits partial contact/separation under the loads and the contact region is a non-linear function of the load magnitude, and some new results are presented by adopting the inverse technique.

TL;DR: In this paper, a method based on thermography with an infrared (IR) scanner has been used to detect prefabricated defects within sandwich panels, which had faces of glass/polyester composite laminates (GRP) and a core of rigid cellular PVC foam.

TL;DR: In this paper, the nonlinear response of initially imperfect plates is determined from the numerical solution of the governing differential equation, and the static response is superimposed on the static displacements in the second phase of the solution.

TL;DR: In this paper, a higher-order theory of laminated composites under in-plane loads is developed and the displacement field is expanded in terms of the thickness co-ordinate, satisfying the zero shear stress condition at the surfaces of the laminate.