A Rod-Explosive Technique for Testing Structural Responses Induced by X-Ray Blow-Off Impulses

Abstract

When a structure is irradiated by a pulsed cold X-ray with high energy density, the instantaneous deposition of energy will induce melting, vaporization, and sublimation of the outer layer of material(s). As a result, the material(s) will blow off and hence lead to a so-called blow-off impulse. This kind of impulsive load will cause high-level structural responses. In order to investigate the effects, various test simulation techniques, such as the light-initiated high explosive (LIHE) technique, the spray lead at target (SPLAT) technique and the sheet-explosive technique, were developed due to the lack of proper X-ray sources. This paper presents a rod-explosive technique developed from the sheet-explosive technique. In this technique, the main property of the explosive, i.e. the specific impulse, is determined by using a pendulum test facility. The simulation load (equivalent to the cosine-distributed specific impulse on a conical shell induced by X-ray) is designed by load discretization and impulse equivalence. Numerical simulations of structural responses to both X-ray loads and rod-explosive loads were performed for validating the test simulation technique. An application example of testing a complex structure is briefly given in the end. The rod-explosive technique has the features of low costs and rather high fidelities. It provides a new approach for testing the structural responses induced by X-ray blow-off impulses.

Hyperelastic behavior of two rubber materials under quasistatic and dynamic compressive loadings — testing, modeling and application

“…Then according to the test data, the mechanical behavior at the strain rate of order 10 3 s -1 was characterized by the Ogden constitutive models. Finally, an application example the two materials are used where as a combined buffer to shape the impulses generated by rod-explosive [20,21] is given to illustrate the validity of the dynamic constitutive models.…”

“…Then structural responses will be caused and may result in damage or failure of the structure. Several researchers experimentally simulate this kind of mechanical effects using the rod-explosive technique [20,21].…”

“…The experimental configuration of the rod-explosive loading test is shown schematically in Fig. 6 [21]. The test item is a cylindrical steel shell with the diameter of 265 mm, length of 380 mm and thickness of 4 mm.…”

“…The test item is a cylindrical steel shell with the diameter of 265 mm, length of 380 mm and thickness of 4 mm. Nineteen pentaerytritol tetranitrate (PETN) explosive rods (3 mm wide and 0.47 mm thick) were used to generate discrete impulsive loads to simulate the impulse induced by X-ray, which is approximately continuously distributed as a cosine function [21,31]. A layer of RB-55 rubber (2.82 mm thick) and a layer of FM-32 foam rubber (8.14 mm thick) are combined as a buffer to shape the rod-explosive loads to be closer to a cosine distribution.…”

Wavelet Analysis of Transient Signals of Structural Responses to Impulsive Loads

“…There is a wide frequency band in a structural transient response to an impulsive load [1]. The transient measurement is easy to be influenced by environmental factors.…”