Download or read book Input output Characterization of Fiber Composites by SH Waves written by John D. Renneisen and published by . This book was released on 1988 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Input-output characterization of fiber composites is studied theoretically by tracing SH waves in the media. A fiberglass epoxy composite is modeled as a homogeneous transversely isotropic continuum plate. The reflection of an SH wave at a stress-free plane boundary in a semi-infinite transversely isotropic medium is considered first. It is found that an incident SH wave reflects only a similar SH wave back into the medium. It is also established that the angle of reflection of the reflected wave is equal to the angle of incidence of the incident wave. The phase velocity of the SH waves and the delay time of the SH waves in reaching the receiving transducer are computed as functions of a reflection index, defined as the number of reflections of the SH waves from the bottom face of the continuum plate. The directivity function corresponding to the shear stress associated with the SH waves in the continuum plate is also derived as a function of the reflection index. A theoretical output voltage from the receiving transducer is calculated for a tone burst (a periodic input voltage of finite duration). The output voltage is shown for tone bursts of duration 60 microseconds and center frequencies of 0.75, 1.00, and 1.25 MHz. The study enhances the quantitative and qualitative understanding of the nondestructive evaluation (NDE) of fiber composites which can be modeled as transversely isotropic media.

Download or read book Input Output Characterization of Fiber Composites by Sh Waves written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-20 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Input-output characterization of fiber composites is studied theoretically by tracing SH waves in the media. A fiberglass epoxy composite is modeled as a homogeneous transversely isotropic continuum plate. The reflection of an SH wave at a stress-free plane boundary in a semi-infinite transversely isotropic medium is considered first. It is found that an incident SH wave reflects only a similar SH wave back into the medium. It is also established that the angle of reflection of the reflected wave is equal to the angle of incidence of the incident wave. The phase velocity of the SH waves and the delay time of the SH waves in reaching the receiving transducer are computed as functions of a reflection index, defined as the number of reflections of the SH waves from the bottom face of the continuum plate. The directivity function corresponding to the shear stress associated with the SH waves in the continuum plate is also derived as a function of the reflection index. A theoretical output voltage from the receiving transducer is calculated for a tone burst (a periodic input voltage of finite duration). The output voltage is shown for tone bursts of duration 60 microseconds and center frequencies of 0.75, 1.00, and 1.25 MHz. The study enhances the quantitative and qualitative understanding of the nondestructive evaluation (NDE) of fiber composites which can be modeled as transversely isotropic media. Renneisen, John D. and Williams, James H., Jr. Unspecified Center NAG3-328; RTOP 506-43-11...

Download or read book Acousto ultrasonic Input output Characterization of Unidirectional Fiber Composite Plate by SH Waves written by and published by . This book was released on 1987 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Acousto ultrasonic Input output Characterization of Unidirectional Fiber Composite Plate by SH Waves written by James H. Williams and published by . This book was released on 1987 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1990 with total page 976 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

Download or read book Acousto ultrasonic Input output Characterization of Unidirectional Fiber Composite Plate by P Waves written by Peter Liao and published by . This book was released on 1988 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: The single reflection problem for an incident P wave at a stress free plane boundary in a semi-infinite transversely isotropic medium whose isotropic plane is parallel to the plane boundary is analyzed. It is found that an obliquely incident P wave results in a reflected P wave and a reflected SV wave. The delay time for propagation between the transmitting and the receiving transducers is computed as if the P waves were propagating in an infinite half space. The displacements associated with the P waves in the plate and which may be detected by a noncontact NDE receiving transducer are approximated by an asymptotic solution for an infinite transversely isotropic medium subjected to a harmonic point load.

Download or read book Acousto ultrasonic Input output Characterization of Unidirectional Fiber Composite Plate by SV Waves written by Peter Liao and published by . This book was released on 1988 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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Download or read book Acousto Ultrasonics written by J. Duke and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Finding and slzmg cracks and other crack-like discontinuities has been the center of attention for scientists and engineers developing and using nondestructive evaluation (NDE) technology. However, with advanced mate rials being "engineered" and used in critical structural components, a new for NDE has emerged. Whereas many traditional engineering materi challenge als fail due to the initiation and self-similar propagation of a crack, reinforced composite materials degrade and fail in a manner more analogously to the collapse of a structure. Consequently the NDE of such materials involves assessing the combined effect of the material's damaged condition rather than identifying and sizing single critical imperfection. In 1979 Alex Vary, seeking to address the challenge confronting the NDE of advanced fiber reinforced composite materials began work on a new method of materials characterization. Focusing on the problem of evaluating graphite fiber reinforcedl epoxy laminated plates; Vary used a piezoelectric transducer to excite a mechanical disturbance in a plate and, with a sensi tive piezoelectric transducer monitored the disturbance on the same surface of the plate. (Placing the transducers on the same surface was primarily for practical purpose but their displacement in the direction of anticipated service load was of fundamental significance!) To quantify this observation, he counted the number of excursions, of the resulting electrical signal, above a arbitrary voltage threshold; a procedure frequently used for acoustic emission signal analysis.

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Aeronautical Journal written by and published by . This book was released on 1988 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1991 with total page 1690 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Annual Index Corporate author written by and published by . This book was released on 1987 with total page 1028 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Engineering Index Annual written by and published by . This book was released on 1989 with total page 2152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its creation in 1884, Engineering Index has covered virtually every major engineering innovation from around the world. It serves as the historical record of virtually every major engineering innovation of the 20th century. Recent content is a vital resource for current awareness, new production information, technological forecasting and competitive intelligence. The world?s most comprehensive interdisciplinary engineering database, Engineering Index contains over 10.7 million records. Each year, over 500,000 new abstracts are added from over 5,000 scholarly journals, trade magazines, and conference proceedings. Coverage spans over 175 engineering disciplines from over 80 countries. Updated weekly.