ASTM D5397 Notched Constant Tensile Load Test equipment for Geosynthetics Polyethylene Geomembrane Stress Crack Resistance test
ASTM D5397 – Single Point Notched Constant Tension Load Test A more reliable test is ASTM D5397 Appendix X1 – Single Point Notched Constant Tension Load test (SP-NCTL). This test places a dumbbell shaped test specimen of HDPE with a central notch under a constant tensile load (30% of the yield strength) in a wetting agent at 50°C. This is a more stringent test. The specimen is kept in tension throughout the test. The Geosynthetic Research Institute (GRI) has an internationally recognised specification for HDPE geomembranes (Geosynthetic-institute.org, 2016), in which the ESCR value tested to ASTM D5397 must be greater than 500 hours.
ASTM D5397-20
Standard Test Method for Evaluation of Stress Crack Resistance of Polyolefin Geomembranes Using Notched Constant Tensile Load Test
This test method is used to develop test data from which the susceptibility of polyolefin geomembrane sheet material to stress cracking under a constant tensile load condition and an accelerated environmental condition can be evaluated.
How to Use ASTM D5397 Notched Constant Tensile Load Tester
test summary
The testing method involves subjecting dumbbell shaped notched specimens of polyolefin sheets to a constant tensile load at high temperatures in the presence of surfactants. Regularly conduct separate tests for each working position, and conduct parallel tests for every three positions as a group, with each group loaded with different yield stresses; Equipped with automatic temperature control and elevated water bath; 30 workstations, supporting 10 sets of tests under 20% -65% yield stress, with automatic calculation of load mass for each set; Provide two methods for determining time sequence and damage time; During or after testing, you can view the fracture time and average fracture time of each specimen under all stresses for the purpose of analyzing the results.
sample
The "NCTL" testing method places the specimen under different constant tensile loads and applies 20% -65% of the material's yield strength to the dumbbell shaped specimen. Before the sample test, a groove should be cut to a depth of 20% of the sample thickness, and then immersed in a surface active agent with a concentration of 10% at a temperature of 50 ° C. During this accelerated aging process, measure the time for sample destruction and plot the results as a load and destruction time graph. NCTL provides information on material plastic failure and brittle failure. The resistance of materials to stress cracking strength is the transition time between two failure modes.
Sample preparation and installation
Take samples in a specific direction using the provided cutting tools.
The sample thickness is 20%, and the notch device is placed in the middle of the sample along the vertical width direction.
The sample has installation holes with punching devices at both ends.
Secure all protective covers onto the mounting holes.
Install the sample onto the sample hook. (Install the hook first).
Test report
Complete identification of test materials
Report average failure time and coefficient of variation values
If I miss anything about the notch constant tensile load tester. Alternatively, if you have more detailed information, you can send an email to export@unitedtest.com
