Dear Rushna,

I have come across a review paper by Sansalone, M. from Cornell University
titled "Impact-echo: The complete story". I think it would be of your
interest. Here is its abstract and source:

Title:	Impact-echo: The complete story
Author:	Sansalone, Mary. 
Source:	ACI Structural Journal. v 94 n 6 Nov-Dec 1997. p 777-786.
(ACI = American Concrete Institute)

Abstract: 
     
Impact-echo's history is an interesting story of how a real need for
nondestructive test methods for flaw detection in concrete structures led
to a systematic and sustained basic and applied research effort to develop
such a method, beginning in 1983, at the National Bureau of Standards, and
continued since 1987 at Cornell University. This paper discusses the
contributions of the people and the organizations who carried out the
theoretical, numerical, laboratory, and field studies that established the
method and who developed the software and instrumentation that gave rise
to a patented impact-echo field system. It also documents how this effort
was undertaken and sustained with government and industry funding.
Subsequently, this paper draws on knowledge gained over twelve years of
research to provide, for the first time, a unified explanation of
impact-echo theory as it applies to the testing of structural elements,
including plates (slabs, walls, bridge decks, pavements, etc.), bars
(beams and columns), and hollow cylinders (pipes and tunnel and mine shaft
liners) and to the detection of flaws within these elements. The last key
pieces fell into place in 1995, and it is now possible to explain in a
concise and coherent way the principles upon which impact-echo testing is
based. (Author abstract) [References: 33]

Sincerely,

Kamaiton Wongkaew

Ph.D. Candidate
Structures Area
School of Civil Engineering
Purdue University
West Lafayette, IN 47907
USA

On Tue, 7 Sep 1999, Begum RB wrote:

> 
> I have modelled the impact echo system using ANSYS. I have simulated a
> crack in concrete, and applied an impact of 1/2 sin wave, the results are
> good. I want to know if anybody has done something similar.
> 
> Rushna
> 
> 





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