From the GMA Techline
Subject: Break/yield strength —I am a structural engineer working in Chile. I used the following text from your organization: GM13, GM17, and GM19.
About GM13 (Rev.8: July 10, 2006), page 10 from this text shows yield strength and break strength for HDPE geomembrane-textured. The table 2b shows yield strength > break strength. Is that correct? (Juan, Chile)
Reply: The break strength being lower than the yield strength in all 3 of these textured geomembrane specifications is correct. If you go to the smooth [geomembrane] tables, you will see the inverse.
The reason for this reversal is that the texturing process results in a significant shortening of the elongation at break, and the break strength simply cannot get up higher than the yield value. All the tables are correct, but thanks for your question nonetheless.