Characterization of Magnetorheological Impact Foams in Compression.

This study focuses on the development and compressive characteristics of magnetorheological elastomeric foam (MREF) as an adaptive cushioning material designed to protect payloads from a broader spectrum of impact loads. The MREF exhibits softness and flexibility under light compressive loads and low strains, yet it becomes rigid in response to higher impact loads and elevated strains. The synthesis of MREF involved suspending micron-sized carbonyl Fe particles in an uncured silicone elastomeric foam.

Visco-Elastic Honeycomb Structures with Increased Energy Absorption and Shape Recovery Performance Using Buckling Initiators.

Energy-absorbing materials have extensive applications in aerospace and automotive applications. Research has shown buckling initiators, or triggers, in energy-absorbing tubular structures increase the energy absorbed by encouraging the side panels to fold when loaded out of plane in compression conditions. Additively manufactured TPE honeycombs were designed in this study to include these buckling initiators, which introduced a slight decrease in initial weight, as well as initial stress concentrations, while improving crashworthiness characteristics.

Tunable Energy Absorbing Property of Bilayer Amorphous Glass Foam via Dry Powder Printing.

The research in this paper entails the design of material systems with tunable energy-absorbing properties. Hollow glass microspheres of different densities are layered using dry powder printing and subsequently sintered to form a cellular structure. The tunability of the bilayer foams is investigated using various combinations of hollow microspheres with different densities and different thickness ratios of the layers.

Bending Properties of an Extensile Fluidic Artificial Muscle.

Low stiffness, large stroke, and axial force capabilities make Extensile Fluidic Artificial Muscles (EFAMs) a feasible soft actuator for continuum soft robots. EFAMs can be used to construct soft actuated structures that feature large deformation and enable soft robots to access large effective workspaces. Although FAM axial properties have been well studied, their bending behavior is not well characterized in the literature.

Vibration Suppression of a Composite Prosthetic Foot Using Piezoelectric Shunt Damping: Implications to Vibration-Induced Cumulative Trauma.

Objective: Energy-storage-and-return (ESAR) prosthetic feet have improved amputee mobility due to their efficient conversion of strain energy to mechanical work. However, this efficiency is typically achieved using light-weight, high-stiffness materials, which generate high-frequency vibrations that are potentially injurious if transmitted to biological tissues. To reduce the vibration which may cause cumulative tissue trauma, high-frequency vibration suppression by piezoelectric shunt damping patches on a commercial ESAR foot was evaluated.

Novel Bending and Helical Extensile/Contractile Pneumatic Artificial Muscles Inspired by Elephant Trunk.

Pneumatic artificial muscles (PAMs) are an extensively investigated type of soft actuator. However, the PAM motions have been limited somewhat to uniaxial contraction and extension, restraining the development of PAMs. Given the current strong interest in soft robotics, PAMs have been gaining renewed attention due to their excellent compliance and ease of fabrication.

Successful Implementation of Unmanned Aircraft Use for Delivery of a Human Organ for Transplantation.

Objective: To understand and overcome the challenges associated with moving life-urgent payloads using unmanned aircraft.

Background Data: Organ transportation has not been substantially innovated in the last 60 years. Unmanned aircraft systems (UAS; ie, drones) have the potential to reduce system inefficiencies and improve access to transplantation.

An Initial Investigation of Unmanned Aircraft Systems (UAS) and Real-Time Organ Status Measurement for Transporting Human Organs.

Organ transportation has yet to be substantially innovated. If organs could be moved by drone, instead of ill-timed commercial aircraft or expensive charter flights, lifesaving organs could be transplanted more quickly. A modified, six-rotor UAS was used to model situations relevant to organ transportation.

Variable recruitment in bundles of miniature pneumatic artificial muscles.

The natural compliance and force generation properties of pneumatic artificial muscles (PAMs) allow them to operate like human muscles in anthropomorphic robotic manipulators. Traditionally, manipulators use a single PAM or multiple PAMs actuated in unison in place of a human muscle. However, these standard manipulators can experience significant efficiency losses when operated outside their target performance ranges at low actuation pressures.

Analytical model and stability analysis of the leading edge spar of a passively morphing ornithopter wing.

This paper presents the stability analysis of the leading edge spar of a flapping wing unmanned air vehicle with a compliant spine inserted in it. The compliant spine is a mechanism that was designed to be flexible during the upstroke and stiff during the downstroke. Inserting a variable stiffness mechanism into the leading edge spar affects its structural stability.

Effect of bladder wall thickness on miniature pneumatic artificial muscle performance.

Pneumatic artificial muscles (PAMs) are actuators known for their high power to weight ratio, natural compliance and light weight. Due to these advantages, PAMs have been used for orthotic devices and robotic limbs. Small scale PAMs have the same advantages, as well as requiring greatly reduced volumes with potential application to prostheses and small scale robotics.