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Arturo Forner Cordero
08-04-1998, 08:38 PM
Dear Biomch-L subscribers:
Here are the postings I received regarding my question about insole fatigue
testing.
Thank you to all who responded to my question.

The best way to know a particular foam's property is to test yourself if
you are able to do. Apparently you are (with Instron). I used to test shoe
insole materials using servo-hydraulic Instron. You can program a test
using the similar impulse to heel strike in running. In terms of number of
cycles, you can set your own standard based on kilometers that you wish the
insole would perform. For example: A average recreational distance runner
runs 20 km per week. He/she performs 25 heel strikes (single foot) in
each 100 meters. If he/she runs 40 weeks a year, he/she has run 800km. If
you want to test out insole performance during this period, you will need
to have 200,000 cycles.
You can compare material properties between pre-test and post-test
(stiffness, energy lost, etc.).

good luck.

Qi Liu

Development Engineer
Orthopedic Surgery Department
UCSF/SFGH
Phone: 415-206-6865
Fax: 415-206-3288
Email: qil@itsa.ucsf.edu



Hello,
You may like to look at our group's www site we have done several studies on
insoles, some using the Instron. www.diabeticfoot.org

Susan

Susan Stacpoole-Shea
Research Fellow,
University of Texas Health Science Center at San Antonio
Mail address:
University Health Center Downtown,
Dept. of Orthopaedics, Podiatry Research,
5th Floor, Room A542,
527 North Leona Street,
San Antonio, Texas, 78207
Email: spod@netconnect.com.au
Fax (210) 358 3824 Phone (210) 358 3897


> -----Original Message-----
>
> Subject: Insole fatigue tests
>
> Dear Biomch-L subscribers:
> I am trying to test the fatigue effect on a Polyurethane foam to be used
> as an insole.
> In the literature review I have found some interesting papers by D.J.
> Pratt et al.
> My questions are:
> 1. Is there any additional reference about how long should an insole
> maintain its absorption and cushioning properties?.
> 2. If so, in which way it could be tested?.
> My goal is to define a testing procedure to test a shoe incorporating an
> insole by means of an Instron machine, controlling the applied load and
> establishing the number of cycles (steps will be simulated by means of a
> rectified sine wave).
> Thanks in advance,
> Arturo Forner
> Instituto de Biomecanica de Valencia
> Valencia. Spain.
> Tel. + 34 96 1366032
> Fax. +34 96 1366033
>


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