University of Michigan

Anthony M Waas

Ellen M Arruda

Michael D Thouless

Nicholas Alexander Kotov

Jonathan Wesley McGee

Tanaz Rahimzadeh

Sean Ahlquist

Paul Podsiadlo

Frank E Filisko

Carlos A Pons Siepermann

Ryan M Anderson

Ming Yang

Yuan Lin Kevin Lim

Chongyu Brian Wang

Keqin Cao

Kaajal Raj Juggernauth

Bong Sup Shim

Michael Thouless

Methods to increase structural performance, strength, and durability of textile-reinforced composite materials are provided. The textile reinforcement may be knitted, for example, in a flat bed weft knitting machine. The method may include pre-stressing a textile reinforcement preform by applying tension. A polymeric precursor may be introduced to the pre-stressed textile reinforcement preform. The polymeric precursor may then be cured or consolidated, followed by releasing of the applied tension to form the composite article comprising polymer and the pre-stressed textile reinforcement. In other aspects, a composite article is provided that has a pre-stressed textile reinforcement structure and a cured polymer. The textile reinforcement may be a knitted, lightweight, seamless, unitary structure. The knitted reinforcement structure may have distinct first and second knitted regions with different levels of pre-stress, thus providing enhanced control over strength, rigidity, and flexibility of the composite article.

Methods to increase structural performance, strength and durability of fabric-reinforced composite materials by pre-stressing

Dissociation of a macroscale version of an aramid fiber leads to the nanofiber form of this polymer. Indefinitely stable dispersions of uniform high-aspect-ratio aramid nanofibers (ANFs) with diameters between 3 and 30 nm controlled by the media composition and up to 10 &#x3bc;m in length are obtained. ANFs can be processed in transparent thin films using layer-by-layer assembly (LBL) with superior mechanical performance.

Synthesis and use of aramid nanofibers

A protective device and method of design to protect against multiple blast and impact events for use in any application in which a delicate target has to be protected. The protective device for mitigating the effects of blast or impact employs a first layer having a first acoustic impedance and a second layer having a second acoustic impedance. The second acoustic impedance is different than the first acoustic impedance. The second layer is proximate to the first layer. The first layer and the second layer are chosen collectively to tune the stress waves from the blast or impact events to one or more specific tuned frequencies. A third layer of a visco-elastic material is employed having a critical damping frequency that matches one or more specific tuned frequencies to dissipate the stress waves of the blast and impact event. The third layer is proximate to the second layer.

Blast/impact frequency tuning mitigation

A wind turbine blade includes at least one mandrel and a sock that covers the at least one mandrel. The sock includes a plurality of braided fibers within a matrix material. The fibers can be made of different materials. Also, stiffness of the sock can vary across the wind turbine blade. A method of manufacturing the wind turbine blade is also disclosed.

Textile composite wind turbine blade

Blast/impact frequency tuning and mitigation

A method of manufacturing a nanocomposite includes exposing dry nanoparticles to a dry, solid matrix material or pellets in a container to form a combination which is then agitated by rotating about an axis transverse to a direction of gravity, at room temperature and without grinding objects, to cause a tumbling action between the pellets and the nanoparticles to thereby evenly disperse and coat the nanoparticles directly on outer surfaces of the pellets which remain in a solid phase and of the same size throughout rotating. The method also includes processing the resulting combination, particularly polypropylene pellets and carbon black nanoparticles, by heating to form a viscous combination which is then drawn to form a nanocomposite fiber having carbon black nanoparticles dispersed evenly throughout the polypropylene, with a resulting fiber having a diameter of 30 &#x3bc;m-100 &#x3bc;m and tensile strength of 300-1500% greater than a similar polypropylene fiber produced without the nanoparticles.

Dispersion method for particles in nanocomposites and method of forming nanocomposites

A stiff layered polymer nanocomposite comprising a substrate adapted to receive a plurality of alternating layers of a first material and a second material; wherein the first material and second material are a polyelectrolyte, an organic polymer or an inorganic colloid and said first material and said second material have a chemical affinity for each other, said plurality of layers crosslinked using a chemical or physical crosslinking agent. Thin films that are consolidated and optionally crosslinked can be manufactured into hierarchical laminates with rigid and stress resistant properties.

Ultrastrong and stiff layered polymer nanocomposites and hierarchical laminate materials thereof

Growing community of inventors

Ann Arbor, MI, United States of America

Anthony M Waas