Issue 42

M. Kowalski, Frattura ed Integrità Strutturale, 42 (2017) 85-92; DOI: 10.3221/IGF-ESIS.42.10 88 Specimen Dimensions, mm F m , kN F u , kN F p02 , kN υ sub , - E sub , GPa w h B1 12.2 3.3 20.0 16.2 12.8 0.27 151 B2 12 2.95 17.6 14.5 15.5 0.27 158 B3 11.98 2.96 18.0 14.5 12.2 0.27 157 B4 12.3 3.0 18.2 14.7 13.5 0.27 161 B5 12.5 2.95 17.7 15.1 11.1 0.27 155 B6 12.1 2.85 18.1 14.9 14.2 0.28 160 B7 12.1 2.92 17.7 14.6 13.0 0.27 155 B8 11.88 3.05 18.3 16.0 14.7 0.28 156 Averaged 0.27 157 where: w, h –specimen section dimensions , E sub – substitute Young modulus, υ sub – substitute Poisson ratio, F m – maximum force, F u –Breaking force, F p02 – foce at 0.2% strain. Table 2 : Mechanical properties of the interface zone. Figure 4 : Dimensions of specimen cross section. 2 2 ti ti int ti st E F t t E t w E w h H E w h                    (1) 2 2 int int int ti st E F t t E t w E w h H E w h                    (2) 2 2 st st int ti st E F t t E t w E w h H E w h                    (3) Where: E ti , E in t, E st – Young Modulus of titanium, interface and steel layers respectively, F – force, w, H, h, t – characteristic dimensions of the composite. Among the specimens not used during the study phenomenon of residual stresses relaxation in titanium layer was observed. Relaxation progressed gradually in about 2 weeks after cut (Fig. 5).