Stress-wave propagation

The common civil engineering seismic testing techniques work on the principles of ultrasonic through transmission (UPV), transient stress wave propagation and reflection (Impact Echo), Ultrasonic Pulse Echo (UPE) and Spectral Analysis of Surface Waves (SASW). 

The gauge element in the form of a foil (50 ohms) is normally embedded in materials such that the active gauge element is normal to the stress-wave propagation direction. Manganin is the only in situ stress gauge available for... 

Gurtman, G.A., Review of Techniques Used to Analyze Stress Wave Propagation in Composites, Systems, Science and Software Report No. 3SR-154, Part II, La Jolla, CA, 40 pp., December 1969. 

Seaman, L., SRIPUFF 3 Computer Code for Stress Wave Propagation, Air Force Weapons Laboratory Technical Report No. AFWL-TR-70-51, Kirtland AFB, NM, 370 pp., September 1970. 

Davids, N. (ed.), International Symposium on Stress Wave Propagation in Materials, Interscience Publishers, New York,... 

A Computer Program SRATE for the Study of Sttain-Rate Sensitive Stress Wave Propagation , SandiaCorpRept SC-RR-65-298(1965)... 

When the intensity of the stress waves is reduced so that there is no permanent deformation of the rock, the stress wave propagates thru the rock in an elastic manner, that is, in such a manner that the rock particles are returned to their original position following the passage of the stress wave... 

KC Valanis, S Chang. Stress wave propagation in a finite viscoelastic thin rod with a constitutive law of the hereditary type. In TC Huang, MW Johnson, eds. Developments in Theoretical and Applied Mechanics. New York Wiley, 1965. 

The effective P may be determined with the electron beam apparatus. When the sample (slab geometry) is thick enough to absorb all of the incident electrons, a compressive stress wave propagates from the irradiated region into the sample bulk. A transducer, located just beyond the deposition depth, may be used to record the stress pulse. Alternatively, the displacement or velocity of the rear surface of sample may be observed optically and used to infer the initial pressure distribution from the experimentally measured stress history. Knowledge of the energy-deposition profile then permits the determination of the Gruneisen coefficient. 

Computer simulation of explosive fracture of rock can be carried out with finite difference stress wave propagation codes, such as the YAQUI code (2). YAQUI integrates in time the coupled partial differential equations for the conservation of mass, momentum, and energy. For a compressible fluid, these equations are... 

L. Seaman, "SRI PUFF 8 Computer Program for One-Dimensional Stress Wave Propagation, Final Repo Menlo Park, 1978. 

The basic principle of SHPB experiment is the stress wave propagation theory in elastic slender bar, which is based on two basic assumptions that one is one-dimensional assumption (also known as plane assumption) and other is uniform stress assumption. The one-dimensional assumption considered that each cross section in elastic bars always keeps the plane state in the propagation process of the stress wave in the slender bar. Uniform stress assumption assumed that the stress... 

During the process of stress wave propagation, tensile stresses or shear stresses do occur and cause rock material to fail in tension or in shear. Therefore, a modified principal stress failure criterion is applied to determining material status, which is suitable for describing material tensile failure or shear failure. The modified principal stress failure criterion dictates that when the major principal stress or the maximum shear stress in an element exceeds material tensile or shear strength, the element fails. After an element has failed, it will not be able to sustain any tensile and shear loadings, but it is still able to sustain compressive loading. The normal compressive stresses, and cr, of a failed ele-... 

Roylance D. Stress wave propagation in fibres effect of crossover. Fibre Sci Technol 1980 13 385-95. 

An acoustic impedance may be defined as Z = r/v = s/c p - the latter term found by substituting Eq. 11 into Eq. 10 - and used to describe the stress wave propagation by substitution of Eq. 11 into Eq. 8 and integrating... 

The simplicity of this plastic model is that all the parameter that is required isp , which can be determined through routine static indentation testing, as also demonstrated for various ductile projectiles (steels and brass) impacted on silicon nitride targets [10]. However, pertinent experimental techniques should be sought to determine more accurately the related dynamic patameters such as impact force, stresses, deformation, duration of impact, coefficient of restitution, and stress wave propagations, etc. Frictional constraint by property mismatch between projectiles and targets of dissimilar materials needs to be taken into account in some cases. 

The governing equations of stress waves propagating in three-dimensional space denoted with vector x are as follows ... 

The boundary conditions for the model are defined as the situation in which a given stress wave transmits from adherend 1 into the joint, as shown in O Fig. 29.4. If a strain gage is bonded on adherend 1 far from the joint end, the strain variation due to the stress wave propagation can be measured. In this case, the information of the progressive stress wave can be obtained, but have no information on the stress wave reflection occurring at the joint end. 

If voids exist at the interface between the coating and substrate they may reduce the adhesion by decreasing the effective contact area, acting as stress concentration defects and providing an easy path for fracture initiation and propagation (Ch. 12). Interfacial voids also result in increased contact resistance between film and substrate and decreased thermal conductance across the interface, and present a discontinuity to stress wave propagation. 

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