Accession Number : ADA298741

Title :   A Study of the Behavior of the GRP Hat-Stiffened Panel Bondline Under High Strain Rate Loading.

Descriptive Note : Master's thesis,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING

Personal Author(s) : Ziv, Michael

PDF Url : ADA298741

Report Date : 30 MAY 1995

Pagination or Media Count : 482

Abstract : The effects of strain rate on the large strain compressive behavior of polymer blends is investigated using Dow Chemical Derakane 8084 rubber toughened vinyl ester and Scott Bader Crestomer 1080 as constituent materials. The goal is to evaluate their suitability for use in the stiffener/panel bondline of GRP minesweeping vessels which need to be able to continue their mission in the event of a near field mine detonation. The experimental procedure involved the testing of five blends ranging from 0-100 percent Derakane 8084 by weight at 25 percent increments under compressive loading in a hydraulic testing machine at constant loading rates of 0.01, 0.10, 1.00 and 2.50 nun/sec. These test results were then used to generate a predictive model for the lower yield stress as a function of the applied strain rate which was used to predict the yield stress of each of the blends as well as the pure Derakane 8084 material out to strain rates on the order of l0 sec. The prediction was then compared against results experimentally obtained using a Hopkins on bar. The correlation between the predicted and experimental values was generally good, although universally low by about 10-18% when the Crestomer 1080 concentration was less than 50%. The cause of this deviation is not known, but is likely due to an inertial effect. At concentrations of Crestomer higher than 50%, the rate dependency of the elastic modulus becomes significant due to the viscoelastic nature of Crestomer 1080. Since the model does not account for rate dependency in the elastic modulus, these results are not as accurate. (MM)

Descriptors :   *POLYMERS, *STIFFENING, *STRAIN RATE, *ESTERS, *NAVAL VESSELS(COMBATANT), *MINESWEEPERS, *VINYL RUBBER, PLASTIC DEFORMATION, STRESS ANALYSIS, THERMODYNAMICS, TENSILE STRESS, SHOCK WAVES, VISCOELASTICITY, MODULUS OF ELASTICITY, THESES, GLASS, IMPACT SHOCK, TRANSITION TEMPERATURE, YIELD STRENGTH, DETONATIONS, ENTROPY, COMPRESSIVE PROPERTIES, VINYL PLASTICS, MINES(ORDNANCE), PEEL STRENGTH.

Subject Categories : Polymer Chemistry
      Plastics
      Elastomers and Rubber
      Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE