MEASURING FRACTURE TOUGHNESS-A SIMPLIFIED APPROACH USING CONTROLLED CRACK PROPAGATION

DURING THE LOADING CYCLE OF THE CONVENTIONAL FRACTURE TOUGHNESS TEST, THE POINT OF LOAD APPLICATION REMAINS FIXED WITH RESPECT TO SPECIMEN GEOMETRY EXCEPT FOR SMALL DISPLACEMENTS IN-LINE WITH THE APPLIED LOAD. BY CONTRAST, IN THE PRESENT METHOD THE POINT OF LOAD APPLICATION ADVANCES TOWARD THE CRACKFRONT DURING THE LOADING CYCLE IN A PATH PARALLEL TO THE PLANE OF THE CRACK. SINCE DISPLACEMENT IS THE CONTROLLED VARIABLE, IT IS THUS POSSIBLE TO OBTAIN A CONTINUOUS FUNCTIONAL RELATIONSHIP BETWEEN LOAD AND CRACKLENGTH. IT IS SHOWN THAT THIS RELATIONSHIP IS DIRECTELY RELATABLE TO THE STRAIN ENERGY RELEASE RATE ON CRACK ADVANCE. THE CONCEPT REDUCES THE COMPLEXITY OF FRACTURE TOUGHNESS TESTING TO A LEVEL COMPARABLE TO A CONVENTIONAL TENSION TEST; THAT IS, RECORDING OF LOAD AND DISPLACEMENT. CHARACTERISTIC FEATURES OF THE METHOD ARE VERY STABLE CRACK PROPAGATION, EFFICIENT USE OF TEST MATERIAL, AND THE ABILITY TO MEASURE TOUGHNESS GRADIENTS. RESULTS OF APPLYING THE CONCEPT TO A 7075-T6 ALUMINUM ALLOY ARE PRESENTED.

• Corporate Authors:

  American Society for Testing and Materials (ASTM)

  100 Barr Harbor Drive, P.O. Box C700
  West Conshohocken, PA  United States  19428-2957
• Authors:
  • Weitzmann, R H
  • Finnie, I
• Publication Date: 1972-9

Media Info

• Features: Figures; References;
• Pagination: p. 294-8
• Serial:
  • Journal of Materials
  • Volume: 7
  • Issue Number: 3
  • Publisher: American Society for Testing and Materials (ASTM)

Subject/Index Terms

• TRT Terms: Cracking; Fracture mechanics; Load tests; Stability (Mechanics)
• Uncontrolled Terms: Crack propagation
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00217270
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 2 1973 12:00AM