Tensile modulus laminates

The important tensile modulus (modulus of elasticity) is another property derived from the stress-strain curve. The speed of testing, unless otherwise indicated is 0.2 in./min, with the exception of molded or laminated TS materials in which the speed is 0.05 in./min. The tensile modulus is the ratio of stress to corresponding strain below the proportional limit of a material and is expressed in psi (pounds per square inch) or MPa (mega-Pascal) (Fig. 2-7). 

Typical tension stress-strain curves of baseline and irradiated unidirectional T300/934 composites tested in [0] and [90] orientations at three different temperatures (121 are shown in Figures 11 and 12. Irradiation had essentially no effect on the fiber-dominated tensile modulus of the [0] specimen and caused only a small (10-15%) reduction in strength at the low and elevated temperatures. For the matrix-dominated [90] laminates, irradiation caused a very substantial decrease in strength at three test temperatures (-38% at -157°C, -26% R.T., -13% 121°C). Irradiation increased the modulus at -157°C and R.T. (10 - 15%), but lowered it at 121°C (-15%). These results are consistent with results obtained on the neat resin specimens discussed above. 

A thin molding of an acetylene-terminated phenylquinoxaline, fabricated by compression molding at 316°C for 26 hr and at 371°C for 5 hr, gave tensile strength of 103 MPa (15,000 psi), tensile modulus of 2.62 GPa (380,000 psi) and elongation of 5% (46). Preliminary unidirectional graphite fiber laminate properties are reported in Table VI. 

The same laminate system was used by all laboratories, namely a laminar structure with five layers based on polypropylene (PP), an adhesive, an ethylene vinyl alcohol (EVOH) layer another adhesive and another polypropylene layer. This is designated PP/adh/EVOH/adh/PP and was used in both fixed arm peel tests and T-peel tests. Peel specimen were 15 mm in width and a notional 100 mm in length. The peel arms were PP/adh (with a thickness of 51pm) and EVOH/adh/PP (with a thickness of 75pm). Although there is no rigorous value for modulus for such multi-layered arms, we have obtained a tensile modulus value for each arm and assumed the materials of the arms to be uniform for the purposes of our calculations. 

PC/SAN blends have been found to exhibit maximal properties at 25-27 wt% AN. This was evidenced by the improvanent in lap shear adhesion of compression-molded laminated sheets of PC and SAN copolymers, and in tensile modulus and elongation at break, improved notched impact Izod strength, and inward shifts of the glass transition temperatures of PC and SAN blend components with respect to their homopolymer values. PC and SAN were found to be partially miscible. The 25-27 wt% AN was found close to the azeotropic composition of SAN. 

A two component epoxy, laminating adhesive system for sandwich panel construction, for application by spray or roller and offering rapid strength development (i.e. having a limited open time), high tensile modulus and strength. 

Figure 1.6(a) The effect of fibre orientation on composite tensile modulus. Calculated for a 60 v/o, unidirectional laminate. The angle refers to that between the fibres and the load axis. 

Figure 4.6 Effect of glass content on tensile modulus and flexural modulus for a variety of glass-reinforced laminates (Arvesen).

Figure 9.3 Tensile modulus of the resin tensile strength of GRP laminates as a function of water uptake after periods of immersion at various temperatures between 30°C and 100°C up to the onset of equilibrium absorption (Pritchard and Speake).

Novel laminates were obtained by UV-curing after the resin was transferred by infusion between double flexible tooling process (RIDFT) [185]. The production time has significantly shortened and depends on the UV exposure interval. Experimental data confirmed some of the properties (tensile strength) of the new materials were comparable to those obtained by thermal curing, while others (tensile modulus) were higher. 

Another utilization of PA wastes originating from carpets is the application of face fibres and textiles as fibrous fillers for the manufacture of composites and laminates [52,53]. Ttimmed carpets were soaked with urea-formaldehyde resins, and subsequently pressed at 150-200°C and 3.4 MPa. The products are characterized by good mechanical properties (tensile modulus of 2.4-2.S GPa). 

Tensile modulus of the composite laminate in axial direction of the pipe Tensile modulus of the composite laminate in circumferential direction of the pipe... 

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