ASTM E1820-21 Standard test method for measurement of fracture toughness

ASTM E1820-21 Standard test method for measurement of fracture toughness

In ASTM E1820-11 the material fracture toughness values are identified. The presence of pre-existing sharp, fatigue cracks are considered. This method is characterized by its resistance to stationary crack fracture, fracture after some stable tearing, stable tearing onset, and sustained stable tearing. This test method is particularly useful when a material response cannot be anticipated before the test.

    Scope:

    ASTM E1820-21 gives procedure and guidelines to determine the fracture toughness using K, J, and CTOD (d) parameters. Toughness is measured in the R-curve format or as a point value.

    Test Procedure:

    The Overall objective of this method is to develop a force-displacement record to evaluate J, K, and CTOD. Two procedures are used here, first, is a Basic procedure used to determine the K, J, and CTOD without using a crack extension measurement device. The second one is the complete procedure to evaluate the fracture toughness resistance curve using crack extension measurement equipment. This also includes the evaluation of single-point toughness values. The basic procedure utilizes a force versus displacement plot and is directed toward obtaining a single fracture toughness value such as KIc, Jc, or δc. Optical crack measurements are utilized to obtain both the initial and final physical crack sizes in this procedure. Multiple specimens can be used to evaluate J at the initiation of ductile cracking, JIC, or δIc. The resistance curve procedure utilizes an elastic unloading procedure or equivalent procedure to obtain a J or CTOD-based resistance curve from a single specimen. Crack size is measured from compliance in this procedure and verified by post-test optical crack size measurements. The overall procedure for this method is initially to prepare a sample/specimen. The specimen dimension is then measured and the temperature is kept stable. Then the alignment is done for bend testing and compact testing. Then the Basic procedure involves loading a specimen to be selected displacement level and determining the amount of crack extension that occurred during loading. After unloading crack size is measured and the resistance curve is plotted. Figures 1,2 show the specimen requirements. 

    Test Specimen:

     

    Figure 1: Fatigue Crack Starter Notch ConfigurationsC:\Users\Pratik\OneDrive\Desktop\tempsnip.png

    Figure 2: Recommended Single Edge Bend [SE(B)] Specimen

    The two side planes and the two edge planes shall be parallel and perpendicular as applicable to within 0.5°. The machined notch shall be perpendicular to specimen length and thickness to within 62°.

    Data:

    Special requirements for testing single edge bend specimen

    Calculation of K For the bend specimen at a force P(i), calculate K as follows,

    Where,

    Calculation of J:

    For the single edge bend specimen, calculate J as follows:

    Where,

    Jel = elastic component of J, and

    Jpl = plastic component of J.

    Conclusion:

    Hence, ASTM E1820-21 gives procedures and guidelines to determine the fracture toughness of metallic materials using various parameters.

    OUR SERVICES

    Core Materials Testing Services

    Metrology

    A variety of microscopy and spectroscopy tools available for precise measurements from the nano to the meter scale.

    Metrology Testing Services POPULAR TESTS:

    TEM SIMS Profilometry

    Materials Testing

    ASTM and ISO standard and custom chemical, mechanical, thermal, corrosion tests, etc. for all materials metals, ceramic or polymers.

    Materials Testing Services POPULAR TESTS:

    Nondestructive Testing Electrical Testing Chemistry Analysis

    Product Testing

    Thousands of tests for product quality and reliability under heat, humidity, temperature shock, vibration, drop, electrostatic discharge.

    Product Testing Services POPULAR TESTS:

    Vibration Testing Humidity Testing Accelerated Aging

    Looking for Material Testing?

    We have already delivered 10000+ Material Test results to top companies

      Send us a request

        Process for testing
        •  

          STEP 01

          You share material and testing requirements with us

        •  

          STEP 02

          We ensure your sample pick-up in an ensured manner

        •  

          STEP 03

          We deliver test report to your inbox

          Let’s work together!

          Share your testing requirements with us and we will be happy to assist you.

          ddd Just share your testing requirements and leave the rest on us!
          • Free, no-obligation consultation
          • Guaranteed confidentiality
          • Quick turnaround time
          • Hassle-free process

            idea icon
            Want to connect with an expert before you leave?