Buckling Test of Flat Cardboard and Examination of Critical Load for Buckling

Abstract

Buckling tests of flat cardboard were conducted using samples of various lengths under the hinged ends, and the critical condition for buckling of flat cardboard was examined. During the test, the relation between the load (P) and loading-line displacement (x) was measured. From the P-x relation, the deflection at the mid-length (δ) and flexural Young's modulus (E_B) were obtained based on elastica theory. The critical load for buckling was estimated from the following five methods: (A) load at the plateau in the P-x relation, (B) onset of nonlinearity in the P-x relation, (C) Southwell's method, (D) minimum value of the δ/P, and (E) Euler's equation. The buckling tests could be performed effectively by the simple apparatus used in this experiment. Additionally, Method D was optimal because the point transiting from compression to flexure could be determined more simply and objectively than the other methods.