Q: We would like to carry out an impact test on geotextiles as described in Koerner (2012), Chapter 2.3.3 Mechanical Properties-Impact Test and Chapter 2.5.5 Impact (Tear) Resistance. I came across the Geosynthetic Research Institute (GRI) GS2 Test Method for Rupture Strength of Geosynthetics by Pendulum Impact testing standard. My questions regard the test apparatus that you are using. Did you purchase this apparatus? Did you build it?
A: Nice to hear from you, and I hope this email finds you well. Yes, we built the apparatus, and we used the following two American Society for Testing and Materials (ASTM) impactors.
- ASTM D1922 Standard Test Method for Propagation Tear Resistance of Plastic Film and Thin Sheeting by Pendulum Method
- ASTM D5942 Standard Test Method for Determining Charpy Impact Strength of Plastics
Both the Elmendorf and Charpy have modifications with points and holders. One can buy used equipment on eBay at a reasonable price. If you want a tutorial on using these devices, check out the well-written thesis by Monteleone (1986).
You should also be aware that most impact testing is now done with a falling-weight device, rather than the pendulum-style equipment you referenced. I would recommend that you also consult the following standards for details about your experimental design.
- ASTM D1790 Standard Test Method for Brittleness Temperature of Plastic Sheeting by Impact
- ASTM D2444 Standard Practice for Determination of the Impact Resistance of Thermoplastic Pipe and Fittings by Means of a Tup (Falling Weight)
- ISO 13433 Geosynthetics–Dynamic Perforation Test (Cone Drop Test)
Koerner, R. M. (2012). Designing with geosynthetics, 6th ed., Vol. 1. Xlibris, Bloomington, Ind.
Monteleone, M. J. (1986). “Puncture and impact behavior of various geosynthetics.” MSCE Thesis, Drexel University, Philadelphia, Pa.