FIGURE 13.8 Carbon-epoxy open-hole tensile specimen tested to failure. TABLE 13.1 Unnotched and Notched Strength Data for [0/+45/90] Carbon/Epoxy Coupons Notch Radius Strength (mm) (MPa) 0 607(c) 1.6 437 2.5 376 3.3 348 hole and the end tab.Make sure eyes are protected in the test area.Load all specimens to failure.Figure 13.8 shows an open-hole tension carbon/epoxy specimen after testing. Notched strength,oN,is calculated based on the gross cross-sectional area (A=wh).A typical set of unnotched and notched strength data for [0/45/ 90]carbon/epoxy coupons is given in Table 13.1.Because the strength model discussed here is restricted to a plate with an infinite width-to-hole diameter ratio,a comparison between experimental data and the notch strength model requires correction for the finite width of the specimen.A common way to correct the data is to multiply the experimental notched strength with a correction factor,K/K,where K is the stress concentration factor for an orthotropic plate of finite width;i.e., oN(∞)=x(w K (13.13) where oN(w)is the experimental strength for a plate of width w,and oN() is the corresponding strength for an infinite plate.A closed-form expression ©2003 by CRC Press LLChole and the end tab. Make sure eyes are protected in the test area. Load all specimens to failure. Figure 13.8 shows an open-hole tension carbon/epoxy specimen after testing. Notched strength, σN, is calculated based on the gross cross-sectional area (A = wh). A typical set of unnotched and notched strength data for [0/45/ 90]s carbon/epoxy coupons is given in Table 13.1. Because the strength model discussed here is restricted to a plate with an infinite width-to-hole diameter ratio, a comparison between experimental data and the notch strength model requires correction for the finite width of the specimen. A common way to correct the data is to multiply the experimental notched strength with a correction factor, K/K∞, where K is the stress concentration factor for an orthotropic plate of finite width; i.e., (13.13) where σN(w) is the experimental strength for a plate of width w, and σN(∞) is the corresponding strength for an infinite plate. A closed-form expression FIGURE 13.8 Carbon–epoxy open-hole tensile specimen tested to failure. TABLE 13.1 Unnotched and Notched Strength Data for [0/±45/90]s Carbon/Epoxy Coupons Notch Radius (mm) Strength (MPa) 0 1.6 2.5 3.3 607 (σ0) 437 376 348 σ σ N N w K K ( ) ∞ = ( ) ∞ TX001_ch13_Frame Page 176 Saturday, September 21, 2002 5:07 AM © 2003 by CRC Press LLC