Deformation of an elastic plate with an edge notch under the action of a plane shock wave: experimental research

Abstract

The dynamics of a thin elastic plate with an edge notch under the action of a weak shock wave in air is experimentally studied. It is shown that the notch has a significant effect on the deformation process Keywords: thin elastic plate, edge notch, weak shock wave, deformation process Introduction. Special-purpose or process-induced inhomogeneities such as inserts, cover plates, notches, cracks, and holes in structural members (plates or shells) have a strong effect on their behavior under various loads. Such inhomogeneities influence the stress-strain state, critical load, and ultimate strength. Let us mention some recent publications addressing problems for bodies with various stress concentrators under static and dynamic loads.For example, plates under uniaxial or biaxial tension and shear were considered in the paper [2], which established how the thickness of the plate near holes should vary to decrease the stress concentration. The influence of a notch on the frequency characteristics of a plate was examined in [10]. A number of qualitative mechanical effects in a thin open spherical shell with an oblong elliptic hole were revealed in [11]. The change in the energy of an elastic plate after making a circular hole in it was studied in [12]. The stress-strain state at the boundary of a circular hole and at the interface between a plate and an eccentric circular cover plate was analyzed in [3]. The influence of rectangular plates reinforcing a cylindrical shell on the critical load, frequency, and vibration mode was experimentally examined in [13]. The design of a compound plate weakened by a periodic set of cracks was considered in [4]. Orthotropic plates weakened by a periodic number of collinear cracks were addressed in [7]. The exact solution (as a function of four constants of integration) for and an equation for the critical compressive load of a column with an arbitrary number and arrangement of cracks were obtained in [8]. The flexibility matrix with a crack and stiffness coefficients for a rotor were found in [9]. The deformation of elastic plates with a central notch parallel to two clamped edges under the action of a shock wave was experimentally studied in [6].The present paper outlines a procedure and results of experimental study of the influence of an edge notch on the nonstationary behavior of a thin elastic plate clamped at two opposite edges and subjected to the action of a normally incident staircase shock wave.1. Method of Analysis. The shock wave was generated in a diaphragm-type shock pipe. The experimental procedure from [6] was mainly used. A tested rectangular plate is made of SF-1-150 fiberglass plastic (GOST 10316-78) with density r = 1.7 g/cm 3 and elastic modulus E = 2.6×10 10 Pa and had a thickness of 2.5 mm, width a = 140 mm, and length l = 210 mm. The 140´250 mm plate was rigidly fixed on the short sides between two steel frames 18 mm thick each. The inside dimensions of the frames coincided with the effective cross-section of the diaphragm-type shock tube; the outside dimension...

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