摘要:
A method according to the present invention, it is possible to accurately measure the stretch-flangeability of sheet metal materials without size effects even when a small amount of specimen is used, compared with the stretch-flangeability established as an international standard, and to measure the stretch-flangeability in the local region. The method according to the present invention includes (a) performing a computer simulation of a small-scale specimen having a predetermined size by using finite element analysis to determine a size of the small-scale specimen; (b) using a standard-scale specimen having the same material as the small-scale specimen specified in the step (a) to perform a punching process specified in the standard testing method; (c) observing a distribution pattern of shearing defects in a hole-edge region of the specimen having performed the punching process, and evaluating a hole expansion ratio; (d) comparing the hole expansion ratio and the distribution pattern of shearing defects between the small-scale specimen and the standard-scale specimen to verify measurement reliability for the stretch-flangeability of the small-scale specimen; and (e) using the size of the small-scale specimen having verified the measurement reliability to evaluate stretch-flangeability.
摘要:
A method according to the present invention, it is possible to accurately measure the stretch-flangeability of sheet metal materials without size effects even when a small amount of specimen is used, compared with the stretch-flangeability established as an international standard, and to measure the stretch-flangeability in the local region. The method according to the present invention includes (a) performing a computer simulation of a small-scale specimen having a predetermined size by using finite element analysis to determine a size of the small-scale specimen; (b) using a standard-scale specimen having the same material as the small-scale specimen specified in the step (a) to perform a punching process specified in the standard testing method; (c) observing a distribution pattern of shearing defects in a hole-edge region of the specimen having performed the punching process, and evaluating a hole expansion ratio; (d) comparing the hole expansion ratio and the distribution pattern of shearing defects between the small-scale specimen and the standard-scale specimen to verify measurement reliability for the stretch-flangeability of the small-scale specimen; and (e) using the size of the small-scale specimen having verified the measurement reliability to evaluate stretch-flangeability.
摘要:
Disclosed is a preparation method for a composite which comprises the following steps: (a) preparing unit metal pieces comprising two or more types of different metals; (b) circumferentially arranging the two or more types of unit metal pieces in a mold comprising upper and lower dies; (c) applying compressive stress to the loaded metal pieces using the upper and lower dies; and (d) rotating the upper and lower dies in one or two directions to apply torque in the pressed state.
摘要:
Disclosed is a preparation method for a composite which comprises the following steps: (a) preparing unit metal pieces comprising two or more types of different metals; (b) circumferentially arranging the two or more types of unit metal pieces in a mold comprising upper and lower dies; (c) applying compressive stress to the loaded metal pieces using the upper and lower dies; and (d) rotating the upper and lower dies in one or two directions to apply torque in the pressed state.