Accession Number : ADA304402

Title :   The Effect of Frequency, Temperature and Materials Structure on Fatigue Crack Propagation in Polymers.

Descriptive Note : Doctoral thesis,

Corporate Author : LEHIGH UNIV BETHLEHEM PA

Personal Author(s) : Skibo, Michael D.

PDF Url : ADA304402

Report Date : 1977

Pagination or Media Count : 182

Abstract : The effect of cyclic frequency, temperature and internal structure on the fatigue crack propagation (FCP) response of polymers of varied structure and properties was evaluated comprehensively. Crack propagation data in poly(methyl methacrylate) (PMMA), poly(vinyl chloride) (PVC), polystyrene (PS), polycarbonate (PC), and polysulfone (PSF) were obtained as a function of frequency. These results determined over a maximum frequency range of 0.1 to 100 Hz show frequency sensitivity to be a function of several, sometimes competitive, factors. The importance of two of these factors, strain rate and creep crack growth on fatigue crack propagation are isolated through waveform studies. Another parameter, the B transition, seems to play a dominant role with the FCP frequency sensitivity being a maximum for polymers where the B transition at room temperature occurs in the range of the experimental test frequency. This correlation was further examined by evaluating the FCP frequency sensitivity of PMMA, PSF, and PC as a function of temperature. The results are rationalized in terms of crack tip

Descriptors :   *POLYSTYRENE, *POLYMETHYL METHACRYLATE, *CRACK PROPAGATION, *POLYVINYL CHLORIDE, SURFACE ANALYSIS, STRESS ANALYSIS, STRUCTURAL ANALYSIS, CRACKING(FRACTURING), MOLECULAR WEIGHT, SYNTHESIS(CHEMISTRY), THESES, COPOLYMERS, TOUGHNESS, STRAIN RATE, CROSSLINKING(CHEMISTRY), TEMPERATURE GRADIENTS, STRUCTURAL RESPONSE, CREEP, FATIGUE(MECHANICS), EPOXY RESINS, THERMAL STRESSES, FATIGUE TESTS(MECHANICS), CYCLIC LOADS, POLYCRYSTALLINE, SULFONES, PLASTICIZERS, ACETAL RESINS.

Subject Categories : Polymer Chemistry
      Plastics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE