Experimental and Applied Mechanics

Experimental Modal Analysis of an Inflatable, Self-rigidizing Toroidal Satellite Component (Experimental and Applied Mechanics) Part 2

Noncontact Testing and Data Analysis Experimental Procedure Careful selection of excitation signal (specific length and bandwidth) was found to be critical for a flexible inflatable torus when trying to obtain reliable vibratory responses with reasonable accuracy. Since by narrowing down the bandwidth, sufficient input energy could be provided to the entire structure and the global […]

Selective excitation using phase shifted ultrasound radiation force from focused transducers in air (Experimental and Applied Mechanics)

ABSTRACT In recent years, it has been demonstrated that the ultrasound radiation force can be used as a noncontact technique for modal excitation. A novel capability of this method is the ability to perform selective excitation. A phase shift is imparted between the modulation signals emitted from a pair of ultrasound transducers focused at different […]

The Steelpan as a tool to incite interest in Engineering Education (Experimental and Applied Mechanics)

ABSTRACT There is an economic imperative to increase the level of innovative activities in developed and developing countries. Universities have been encouraged to increase the number of science and technology graduates. One of the approaches used by universities is the encouragement of minority students, in particular, Black African-American and African-Caribbean students into undergraduate engineering. However, […]

Non-Contacting Strain Measurement in Dynamic Tensile Testing (Experimental and Applied Mechanics) Part 1

ABSTRACT This paper presents the development of a test procedure and application of non-contacting strain measurement in dynamic tensile testing. The strain time histories of test specimens measured by a laser extensometer were derived by a phase-shift technique based on zero-crossing method. The accuracy of proposed procedure was verified by comparing the strain values measured […]

Non-Contacting Strain Measurement in Dynamic Tensile Testing (Experimental and Applied Mechanics) Part 2

Failure Behavior The failure behavior of the composite was recorded using a high speed digital camera (Phantom v.7) at a sampling rate of 10,000 fps. Typical images were chosen to present the cracking pattern of the composite, as shown in Fig. 6. Note that there are three stages in the failure of the composite during […]

Quantification of Micro-Crack Density for Fiber Based Composites (Experimental and Applied Mechanics)

ABSTRACT This paper describes a method for quantifying defects in fiber based composite materials created during the fabrication process. The defects include voids that arise during manufacturing, micro-cracks produced during cure, and delaminations which occur between lamina. In this method, photomicrography technology is used in conjunction with computer aided design (CAD) software. The photomicrographs, stored […]

Dynamic shear response of a polymer bonded explosive using a modified Hopkinson bar apparatus (Experimental and Applied Mechanics)

Abstract An innovative Hopkinson pressure bar system for testing the shear response of materials at high strain rates has been developed. A novel single-lap specimen of a polymer bonded explosive (PBX) is used. Instead of strain gauges mounted on the bars, one quartz force transducer is sandwiched between the clamp and the transmission bar to […]

Shock testing accelerometers with a Hopkinson pressure bar (Experimental and Applied Mechanics)

ABSTRACT The electronic industry continues to dramatically reduce the size of electrical components. Many of these components are now small enough to allow shock testing with Hopkinson pressure bar techniques. However, conventional Hopkinson bar techniques must be modified to provide a broad array of shock pulse amplitudes and durations. For this study, we evaluate the […]

Effect of residual stresses on spallation of the film under impact by coated bullet (Experimental and Applied Mechanics) Part 1

Keywords: Film; impact by coated bullet (ICB); residual stress; spallation; interface 1. Introduction The mechanical reliability of film/ substrate system is largely dominated by the bonding strength between the film and substrate. In order to evaluate the interface strength of film and substrate, many kinds of methods, either quasi-static or dynamic loading have been developed […]

Effect of residual stresses on spallation of the film under impact by coated bullet (Experimental and Applied Mechanics) Part 2

Numerical model and computational results Numerical model The axisymmetric geometry model and the sketches of the mesh are shown in Fig.3. In Fig.3, the X-axis starts from the symmetric axis and is parallel to the interface. Perfect bonding are assumed for the film/ substrate interface, across which the continuity conditions can be interpreted as Where […]

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