| Popis: |
In the present research, first, the equivalent material concept (EMC), proposed originally by the first author to equate a ductile material with a virtual brittle material, was utilized in conjunction with two stress-based brittle fracture criteria, namely the point-stress (PS) and the mean-stress (MS) criteria, to develop two combined failure criteria capable of predicting tensile crack initiation from U-notches in ductile materials. Then, to verify the two failure criteria, several rectangular thin plates weakened by a central bean-shaped slit with two U-shaped ends and made of aluminum alloys Al 7075-T6 and Al 6061-T6 were tested under tension. Experimental observations indicated that Al 7075-T6 plates failed by moderate-scale yielding while Al 6061-T6 by large-scale yielding. It was found that the EMC-MS criterion could predict the experimental results of both materials successfully. Meanwhile, the EMC-PS criterion was found to be accurate for moderate and large notch radii, particularly for Al 6061-T6 material. |
