Issue 35

T. Haiyan, Frattura ed Integrità Strutturale, 35 (2016) 472-480; DOI: 10.3221/IGF-ESIS.35.53 478 heating treatment in water [19], followed by staining, dehydration and transparent disposal. One or two hours later, the sections were embedded with neutral resins. Then the area of fibre bundle was observed under microscope. Tab. 3 demonstrates six layers of micro cross section (from inside to outside) and area of fibre bundle. The first layer (internal layer) Vr=10.65% The second layer Vr=14.33% The third layer Vr=13% The fourth layer Vr =27.3% The fifth layer Vr =34.02% The sixth layer (External layer) Vr=44.29% Table 3 : Six layers of micro cross section (from inside to outside) and area of fibre bundle. Limiting stress and elastic modulus of every bamboo sample were calculated.     0.936 562.69 19.042 588.732 562.69 40.129 0.2219 40.351 40.129 0.955 c f b c f b R V E V R V V            (8) Correlation between elastic modulus, tensile strength and volume fraction of fiber can be obtained when we correlate results obtained above and volume fraction of fiber together, as shown in Fig. 5 and 6. Figure 5 : Correlation between tensile of bamboo strength and volume fraction of fiber.