Use of Statical Indentation Laws in the Impact Analysis of Laminated Composite Plates

Abstract

The low-velocity impact response of graphite/epoxy laminates was investigated theoretically and experimentally. A nine-node isoparametric plate finite element in conjunction with an empirical contact law was used for the theoretical investigation. Theoretical results are in good agreement with strain-gage experimental data. The results of the investigation indicate that the present theoretical procedure describes the impact response of laminate for low-impact velocities.

Damage in woven-fabric composites subjected to low-velocity impact

“…where f is the scalar contact force,`' is the di erence between the displacement of the centre of the nose of the impactor and that of the centre of the mid-surface of the plate and`k' is modi®ed Hertz constant whose value can be calculated by [21,54,55]:…”

Contact and friction in systems with fibre reinforced elastomers

“…If the reinforcement occurs in direction x or y, the contact area is no longer a circle but an ellipse with its principal axes along the directions x and y. The model of Sun et al [17,18], Willis [19] and Swanson [20] agree in the case of an increase of reinforcement in the direction z; they find that the contact area decreases with an increase of the reinforcement but remains circular.…”

“…A variety of elastic models considering adhesion at different levels of elasticity and loads are also available. Elastic contact models considering different levels of anisotropy [15][16][17][18][19][20] and viscoelastic isotropic contact models [11][12][13][14] are available as well. However, a contact model that is able to integrate anisotropic behaviour, viscoelastic behaviour and adhesional forces between the surfaces in contact is not available in literature.…”

“…They obtained an analytical expression for the stress along the axis of the indenter and on the surface. Yang and Sun [17] and Tan and Sun [18] assumed that the contact area and pressure in the case of an orthotropic material could be derived from the isotropic case, replacing the isotropic modulus by the orthotropic one in the loading direction. Willis [19] developed a method to calculate the contact area of a completely anisotropic material by numerically solving a contour integral.…”

A Novel Method for Detecting and Characterizing Low Velocity Impact (Lvi) in Commercial Composite

“…Drop weight impact testing is the most common test for impact damage in composite materials [8]. In drop weight tests, the damage is produced by the low-velocity range impact, using a heavy mass in order to produce a kinetic energy level of interest [9].…”