Carnegie Hall

Abstract Magnetically actuated intelligent structures have shown great promise in various applications ranging from soft robotics to biomedical devices. One important type of structure involves embedding rigid magnets in polymer matrices, thanks to their simplicity in manufacturing and flexibility in structure design. However, accurately modeling their behavior remains challenging due to the strong nonlinear coupling between large deformation and spatially varying magnetic fields. To address this, we employ a fictitious magnetic charge method to transfer the magnetic forces and torques into surface traction under both uniform and nonuniform external magnetic actuation. We implement the proposed method in the commercial finite element software abaqus and validate it through a series of benchmark examples, which cover tuning the area of magneto-mechanical metamaterials, the shape changing of magnetic lattice structures, and the magnetic-field-driven buckling of cellular structures. Our approach enables accurate prediction of shape transformations in magnetically responsive structures, offering a practical tool for the design and optimization of future magneto-mechanical metamaterials and devices.

This paper presents an experimental study on thermal and structural performance of fire-damaged circular reinforced concrete (RC) columns with medium and high strength concretes. A total twelve circular RC columns were exposed to elevated temperatures following the ISO 834 standard fire curves up to 120 min. The investigation focused on the effect of concrete compressive strength and fire duration on the residual axial capacity. The paper presents the temperature radiation into the column’s section versus duration and exterior temperature levels. In addition, detailed deterioration damage of the columns, residual axial load carrying capacity and load-displacement response of columns are presented. Detailed review of experimental work done by others is also presented.

Peatland shifts in vegetation community composition towards woody plants (Gunnarsson et al. 2002) have been shown to lower plant diversity, change community structure, and limit peatland-specific vegetation (Gusewell and Le Nedic 2004, Warren et al. 2009, Farrick and Price 2009, Kolos and Banaszuk

We show that an $n$-dimensional Riemannian manifold with $n$-nonnegative or $n$-nonpositive curvature operator of the second kind has restricted holonomy $SO(n)$ or is flat. The result does not depend on completeness and can be improved provided the space is Einstein or K\"ahler. In particular, if a locally symmetric space has $n$-nonnegative or $n$-nonpositive curvature operator of the second kind, then it has constant curvature. When the locally symmetric space is irreducible this can be improved to $\frac{3n}{2}\frac{n+2}{n+4}$-nonnegative or $\frac{3n}{2}\frac{n+2}{n+4}$-nonpositive curvature operator of the second kind.