Strain Rate Sensitivity of Epoxy Resin in Tensile and Shear Loading

Gilat, Amos; Goldberg, Robert K.; Roberts, Gary D.

The mechanical response of E-862 and PR-520 resins is investigated in tensile and shear loadings. At both types of loading the resins are tested at strain rates of about 5x10(exp 5), 2, and 450 to 700 /s. In addition, dynamic shear modulus tests are carried out at various frequencies and temperatures, and tensile stress relaxation tests are conducted at room temperature. The results show that the toughened PR-520 resin can carry higher stresses than the untoughened E-862 resin. Strain rate has a significant effect on the response of both resins. In shear both resins show a ductile response with maximum stress that is increasing with strain rate. In tension a ductile response is observed at low strain rate (approx. 5x10(exp 5) /s), and brittle response is observed at the medium and high strain rates (2, and 700 /s). The hydrostatic component of the stress in the tensile tests causes premature failure in the E-862 resin. Localized deformation develops in the PR-520 resin when loaded in shear. An internal state variable constitutive model is proposed for modeling the response of the resins. The model includes a state variable that accounts for the effect of the hydrostatic component of the stress on the deformation.

Document ID

20050179433

Acquisition Source

Glenn Research Center

Document Type

Technical Memorandum (TM)

Authors

Date Acquired

September 7, 2013

Publication Date

March 1, 2005

Subject Category

Report/Patent Number

Funding Number(s)

Distribution Limits

Public

Work of the US Gov. Public Use Permitted.

Available Downloads

Name

Type

20050179433.pdf

STI

No Preview Available

NTRS

NTRS - NASA Technical Reports Server

Available Downloads

Related Records