The Nonlinear Thermoviscoelastic Characterizations of FM‐73 Adhesives

Mechanistic Approach to Structural Fire Modeling of Composites

“…The recovery data were found to be non-linear in stress regardless the temperature and stress level and were inconsistent (as discussed above and in Figure 46) with corresponding creep data. Although selection of the expressions in Equation 10 is arbitrary, they are comparable to what other investigators have reported [11,12,15,19].…”

“…Our approach to fitting the creep data was to balance the goodness of the creep fit with how consistency in the stress non-linear parameters. We also made no assumptions about either the stress or temperature dependences before fitting Equation 7 to the creep data as other investigators have Tuttle et al [14] and Peretz and Weitsman [15]. We simply fit all the data with respect to stress and then looked for trends in stress then in temperature.…”

“…An accelerated characterization technique which addresses the effects of elevating the stress levels was developed by Schapery [7,8] and has been successful used by numerous authors [9][10][11][12]. Schapery's iso-thermal, non-linear, viscoelastic hereditary integral is derived from irreversible thermo-dynamics and has been successfully combined with the TTSP by Xiao [13], Tuttle et al [14], and Peretz and Weitzman [15]. Unlike TTSP (which is a linear theory), Schapery's theory requires the use of vertical shifting in the characterization of the viscoelastic non-linearity; non-linearity that may also utilize both creep and creep recovery data in determination of the parameters.…”

Cure shrinkage effects in epoxy and polycyanate matrix composites

“…There were ample quantities of this material available and therefore no restrictions on the thickness or number of laminates which could be produced. A total of 32 runs were made of which 12 were second cure runs where the new prepreg laminate is cured on the previously cured laminate panel. Eighteen runs were made using unidirectional layups and six of these were second cure runs.…”

The strength prediction of adhesive single lap joints exposed to long term loading in a hostile environment

“…Thus it is important to determine the viscoelastic properties of the adhesive to provide reliable prediction of the adhesive behaviour during long-term degradation. Peretz and Weitsman [12] presented creep tests on FM73 bulk adhesive to investigate the viscoelastic characteristics at elevated temperatures. A temperature range of 30 o C to 60 o C was considered and the results showed that it is essential to include thermal and viscous effects in the characterization scheme.…”