1purpose：

This instrument is a standard test instrument for evaluating the stress cracking strength of polyolefin geomembranes using the notch constant load tensile test. Mainly suitable for geomembranes used in landfills. Geomembrane is a waterproof and barrier material based on polymers, such as polyethylene（PE）Geomembrane, polyvinyl chloride（PVC）Geomembrane, chlorinated polyethylene（CPE）Geomembranes and various composite geomembranes.

IIprinciple

This test method involves placing dumbbell shaped samples with incisions taken from polyolefin sheets under constant load tension in a high-temperature surfactant, testing and recording the time of sample fracture. A series of test results at different stress levels can be plotted on the logarithmic axis as a relationship between stress level and fracture time.

Standard Test Method for Evaluating the Stress Cracking Strength of Polyolefin Geomembranes Using Notch Constant Load Tensile Test for Environmental Stress Cracking Resistance of Geomembranes1, abbreviated as“NCTL”。

“NCTL”This test method involves placing the specimen under different constant tensile loads for testing. The yield strength test of materials20-65%Apply the load to the dumbbell shaped specimen. The sample needs to be cut first, and the depth of the cut is equal to its thickness20%And soaked at a temperature of50℃The concentration is10%In one of the active agents. Measure the time of sample failure during this accelerated aging process. Draw the experimental results as a graph of the relationship between load and failure time.NCTLThe test provides information on material plastic and brittle failure. The stress cracking strength of a material is the transition time between these two forms of failure 2。

This instrument complies withCJIndustry Standards for Urban Construction in the People's Republic of ChinaCJ/T234-2006(Appendix)C）AndGB_T 17643-2011regulations.

IIICharacteristics of the instrument

3.1This instrument is designed as a stylish, fully functional, and automated testing equipment.

3.2Adopting touch screen display, Chinese operation interface, simple and clear menu prompts, and accurate time recording.

3.3The control system is operated by DeltaPLCDelta temperature controller and Xinjie human-machine interface touch screen controller. Implement separate timing for each aircraft, and conduct parallel tests every three aircraft as a group, with each group loaded with different yield stresses; Experimental constant temperature water bath with automatic temperature control and lifting; total sorties30Frame, support20%-65%Under yield stress10Group experiment, automatic calculation of loading quality for each group Provide two methods: timing determination method and damage time determination method; After the experiment is completed, the fracture time and average fracture time of each specimen in each stress segment can be checked at any time to facilitate the analysis and judgment of the results.

3.2The sample holder is made of stainless steel material, which is not easy to rust.

3.3The constant temperature medium box has high temperature accuracy and is equipped with a circulating pump to ensure uniform temperature of the test medium and improve the accuracy of the test.

3.4According to the standard, there should be twenty test channels.

4Technical Specifications

1Loading capacity of horizontal bar:≤5kg

2Leverage labor-saving coefficient:3

3Applicable to geomembrane specifications:0.75—3mm

4Number of sample channels:20Rack (can be ordered according to user needs ≤30Frame)

5、Temperature control range: room temperature--70℃

6、Temperature ModulePIDautomatic control

7Temperature control accuracy: ±1℃

8Timing accuracy:1 S

9Display mode: touch screen

10、Inner container size of constant temperature medium box:1200×150×300mm(Length x Width x Height)

5、 Preparation of samples

according toCJIndustry Standards for Urban Construction in the People's Republic of ChinaCJ/T234-2006(Appendix)C）The standard requires the production to comply with Appendix D of GB/T17643-2011 for the determination of tensile load stress (notch constant load tensile load stress test). This instrument is equipped with tools developed by our company.