Connor McMahan

California Institute of Technology | CIT · Department of Mechanical & Civil Engineering

Morphing flat sheets into non-planar shapes enables fast and scalable manufacturing of three-dimensional objects. Here, we investigate the out-of-plane shape morphing capabilities of single-material elastic sheets with architected cut patterns. The sheets are laser-cut into an array of tiles connected by flexible hinges, which enable large deformat...

There is growing interest in creating untethered soft robotic matter that can repeatedly shape-morph and self-propel in response to external stimuli. Toward this goal, we printed soft robotic matter composed of liquid crystal elastomer (LCE) bilayers with orthogonal director alignment and different nematic-to-isotropic transition temperatures ( TNI...

Advances in shape-morphing materials, such as hydrogels, shape-memory polymers and light-responsive polymers have enabled prescribing self-directed deformations of initially flat geometries. However, most proposed solutions evolve towards a target geometry without considering time-dependent actuation paths. To achieve more complex geometries and av...

In this work, we investigate the use of pre-twisted metallic ribbons as building blocks for shape-changing structures. We manufacture these elements by twisting initially flat ribbons about their (lengthwise) centroidal axis into a helicoidal geometry, then thermoforming them to make this configuration a stress-free reference state. The helicoidal...

In this work, we construct an effective continuum model for architected sheets that are composed of bulky tiles connected by slender elastic joints. Due to their mesostructure, these sheets feature quasi-mechanisms -- low-energy local kinematic modes that are strongly favored over other deformations. In sheets with non-uniform mesostructure, kinema...

In this work, we construct an effective continuum model for architected sheets that are composed of bulky tiles connected by slender elastic joints. Due to their mesostructure, these sheets feature quasi-mechanisms – low-energy local kinematic modes that are strongly favored over other deformations. In sheets with non-uniform mesostructure, kinemat...

In this work, we construct an effective continuum model for architected sheets that are composed of bulky tiles connected by slender elastic joints. Due to their mesostructure, these sheets feature quasi-mechanisms -- low-energy local kinematic modes that are strongly favored over other deformations. In sheets with non-uniform mesostructure, kinema...

Stimulus responsive elastomers are advanced engineered materials that perform desired functionalities when triggered by external stimuli. Liquid crystal elastomers (LCEs) are one important example that exhibit reversible actuation when cycled above and below their nematic-to-isotropic transition temperature. Here, we propose a micromechanical-based...

In this work, we investigate the use of pre-twisted metallic ribbons as building blocks for shape-changing structures. We manufacture these elements by twisting initially flat ribbons about their (lengthwise) centroidal axis into a helicoidal geometry, then thermoforming them to make this configuration a stress-free reference state. The helicoidal...

Morphing flat sheets into non-planar shapes enables fast and scalable manufacturing of three-dimensional objects. Here, we investigate the out-of-plane shape morphing capabilities of single-material elastic sheets with architected cut patterns. The sheets are laser-cut into an array of tiles connected by flexible hinges, which enable large deformat...

Objective: The purpose of this manuscript is to compute skin strain data from a flexed biological limb, using portable, inexpensive, and easily-available resources. Methods: We apply and evaluate this approach on a person with bi-lateral transtibial amputations, imaging left and right residual limbs in extended and flexed knee postures. We map 3...

*Objective:* The purpose of this manuscript is to compute skin strain datafrom a flexed biological limb, using portable, inexpensive, andeasily-available resources. *Methods:* We apply and evaluate this approachon a person with bi-lateral transtibial amputations, imaging left and rightresidual limbs in extended and flexed knee postures. We map 3D d...