Buckling of Open Cross-Section Composite Thin Shells
Sergio Pellegrino studies deployable composite shells for large space solar arrays, where lightweight construction and compact storage are essential. A design explored in Caltech's Space Solar Power Project uses slender cylindrical longerons formed from two circular-arc flanges bonded along an edge. Laminates thinner than 0.1 mm permit tight packaging but make bending behaviour sensitive to local geometric imperfections. The talk examines how the size, shape and distribution of those imperfections explain nonlinear moment–rotation measurements and determine overall bending stiffness, connecting detailed structural analysis with prototype observations. Online via Zoom. Tuesday 29 September 2026 at 12:00 EDT (America/New_York; UTC−4). Organized by ASCE Engineering Mechanics Institute — Stability Committee. Researchers, practitioners and students can use Register for Zoom Link on the organizer's page; the event-specific form requests contact and affiliation details. Attendees must acknowledge the organizer's prohibition on unauthorized recording, transcription and meeting-assistant bots. Pellegrino is a professor at the California Institute of Technology.
Multistable structures - from deployable structures to robots
Multistable structures can reversibly change between multiple stable configurations when a sufficient energetic input is provided. While originally the field focused on understanding what governs the snapping, more recently it has been shown that these systems also provide a powerful platform to design a wide range of smart structures. In this talk, I will first show that pressure-deployable origami structures characterized by two stable configurations provide opportunities for a new generation of large-scale inflatable structures that lock in place after deployment and provide a robust enclosure through their rigid faces. Then, I will demonstrate that the propagation of transition waves in a bistable one-dimensional linkage can be exploited as a robust mechanism to realize structures that can be quickly deployed. Finally, while in the first two examples multistability is harnessed to realize deployable architectures, I will demonstrate that bistable building blocks can also be exploited to design crawling and jumping robots. Unlike previously proposed robots that require complex input control of multiple actuators, a simple, slow input signal suffices to make our system move, as all features required for locomotion are embedded into the architecture of the building blocks.