Fig. 3: Imperfection sensitivity of the pressure buckling of magnetic shells.
From: Magneto-active elastic shells with tunable buckling strength
a Knockdown factor, κd, and, b its change under the magnetic field, \({{\Delta }}{\kappa }_{{\rm{d}}}={\kappa }_{{\rm{d}}}-{\kappa }_{{\rm{d}}}{| }_{{B}^{{\rm{a}}} = 0}\) are plotted versus normalized defect amplitude \(\overline{\delta }\). The tested shell specimens are made of MRE-22 or MRE-32 (E = 1.15 MPa, R/h = 79.1 for MRE-22 and E = 1.69 MPa, R/h = 91.3 for MRE-32; see Methods section). The magneto-elastic buckling number Λm = {0.18, 0.09, 0, −0.09, −0.18} is varied by adjusting the external flux density Ba = {−53, −26, 0, 26, 53} mT for the MRE-22 shells and Ba = {−66, −33, 0, 33, 66} mT for the MRE-32 shells. Experimental results are represented by open symbols, and lines are predictions by the axisymmetric shell model. The closed symbols on each line in b represent the onset of the plateau of Δκd, determined as the first point when the derivative of Δκd with respect to \(\overline{\delta }\) is <1%.
