Лако-красочные материалы — производство

As given in Eq. (1), the measurement of crack length can be avoided by tapering the specimen, such that dC/da is a constant. Extensive studies of compliance rate change of Figure 8 Geometry of the wood-wood TDCB specimen for calibration study. Figure 9 Geometry of the FRP-FRP TDCB specimen for calibration study. TDCB specimens with […]

Once the performance of the interface bond was established by the previous delamination (durability) tests, contoured double cantilever beam (CDCB) specimens were designed to conduct mode-I fracture tests. In this study, bilayer CDCB specimens (see Fig. 6) were designed by the Rayleigh-Ritz method [8] and used for fracture toughness tests on bonded FRP-wood interfaces under […]

As indicated in Table 7, the wood moisture content had a major effect on the shear strength of epoxy FRP-wood specimens with RF coupling agent (approximately 42.8% Table 6 Shear Strength of Wood-Wood and Phenolic FRP-Wood Bonded Interfaces Dry Wet Difference Wood-wood 13.50 MPa (1956 psi) 6.12 MPa (887 psi) 54.7% FRP-wood 7.13 MPa (1033 […]

As shown in Table 6, the moisture content in the wood had a significant effect on the shear strength of wood-wood specimens (about 55%); whereas for phenolic FRP-wood speci­mens, there was a less significant influence of moisture content on the shear strength (about 6%). The average percent material (cohesive) failure for the wood-wood samples decreased […]

Tests to establish shear strengths and percent material failures for adhesively bonded wood-wood and FRP-wood interfaces were performed using a modified ASTM D905 6.35 mm (0.25") Figure 5 Modified ASTM D905 specimens for block-shear test. (a) Phenolic FRP-wood specimen; (b) epoxy FRP-wood specimen. tested following the ASTM D905 standard. Initially, all the block-shear samples were […]

Laminated red maple beams were used as the mandrel to apply the Epoxy FRP over the wood by filament winding (Fig. 4). Delamination samples both with HMR and RF cou­pling agents were cut from the epoxy FRP-wood beams, and the final dimensions of the Specimen Coupling agent No. of samples Bondline Average delamination (%) Wood-wood […]

For phenolic FRP-wood bonded assemblies, the following factors relating to the perfor­mance of the bonded interface were investigated: (1) the influence of coupling agents, (2) the influence of clamping pressure, and (3) the influence of open/closed assembly time. The sizes of the specimens used were smaller than those specified in ASTM D2559. Each laminated FRP-wood […]

The ASTM standard test D2559 was developed for specification of adhesives for structural laminated wood products for use under exterior exposure conditions. This standard test could be used to screen the best combination of parameters to achieve an adequate performance of the FRP-wood interface. Following the ASTM specifications, the speci­mens were subjected to the following […]

Two types of FRP-wood interfaces are evaluated: FRP strips (plates) bonded to wood, and wood cores wrapped with FRP by filament winding. The wood material used is red maple, and the reinforcing material consists of either E-glass fiber rovings embedded in a phenolic resin matrix, or E-glass fiber rovings filament wound in an epoxy matrix. […]