We will summarize two mechanical concepts and discuss their relevance to the bending test:

1. Modulus of Rupture: this is a fictitious stress that gives the equivalent stress at maximum moment as if the internal stress distribution were linear.  The modulus of rupture is greater than the maximum axial yield stress (usually the tensile yield stress), but may be less than the minimum axial yield stress (usually compression).

2. Stability: An equilibrium state of a system is stable if, when the the system is disturbed away from the equilibrium state, the system tends to return to the equilibrium state.  We are particularly concerned to know whether the I-beam used in the bending test will be stable during the bending test - including at the point of rupture of the bamboo specimen - given that it is mounted on a relatively small disc.

Last modified: Wednesday, 5 November 2014, 3:12 PM