University of California

Lawrence Livermore National Security, LLC

Other

Jonathan Hopkins

Robert Matthew Panas

Yuanping Song

Andrew J Pascall

Julie A Mancini

Christopher M Spadaccini

Piyush Sheth

Ali Hatamizadeh

Logan Bekker

Lorenzo Valdevit

Babak Haghpanah Jahromi

Amin Farzaneh

Hando Kim

A boundary learning optimization tool for training neural networks with accurate models of parameterized flexure using a minimal number of numerically generated performance solutions generated from different design instantiations of those topologies. Performance boundaries are output by the neural network in optimization steps, with geometric parameters varied from smallest allowable feature sizes to largest geometrically compatible feature sizes for given constituent materials. The plotted performance boundaries define the design spaces of flexure systems toward allowing designers to visually identify which geometric versions of their synthesized topologies best achieve desired combinations of performance capabilities.

Apparatus and method for boundary learning optimization

A pressure sore prevention mattress is provided alternating pressure points on the body of an occupant that is easily transformable between two stable configurations. The four-layer mattress construction has a top foam pad, a webbing layer, a dynamic layer of deformable panels trapezoid-shaped four-bar mechanisms that deform to produce an undulating pattern of peaks, and a base. Panel geometry can determine peak height. The mattress has a spatially hollow geometry that allows natural air convection through the breathable top foam pad to enable drying of moisture as well as the use of forced air convective drying or cooling. The mattress can be transformed from one configuration to the other while the occupant is on the mattress.

Multi-stable compliant-mechanism mattress for bed sore prevention

The present invention provides compliant screws compatible with standard threaded holes that are self-anchoring via auxetic properties. Once a screw has been twisted in place using a mating screw driver, the screw won't be able to be removed unless it is broken, its surrounding material is torn out with the screw, or unless the screw driver itself is again used to twist the screw in the opposite direction. Thus, although reusable, the screw will never come out of its hole in the presence of vibrations or other cyclic or random loading scenarios. The screws are thereby suitable for critical joint applications where screws must never come loose. Non-limiting examples include satellite fasteners, high-speed vehicle bolts, pedicle screws, and other screws used to secure medical implants within a human body.

Compliant self-anchoring screw with auxetic properties

In one embodiment, a shape-reconfigurable structure includes a rigid base having first and second ends, a rigid first beam having a lateral end and a central end, the lateral end being connected to the first end of the base, and a rigid second beam having a lateral end and a central end, the lateral end of the second beam being connected to the second end of the base and the central end of the second beam being connected to the central end of the first beam, wherein the structure can be placed in an expanded orientation in which the first and second beams extend outward away from the base and a contracted orientation in which the first and second beams extend inward toward the base.

Stable shape-reconfigurable structures and mechanisms

The present disclosure relates to a micromechanical displacement logic, signal propagation system that makes use of first and second bistable elements, and first and second mounting structures arranged adjacent opposing surfaces of the first bistable element. A plurality of pivotal lever arms are used to support the first bistable element in either one of two positions of equilibrium. A support structure and a compressible flexure element disposed between the support structure and the first mounting structure apply a preload force to the first mounting structure, which imparts the preload force to the first bistable element. The first bistable element is moveable from one of the two stable equilibrium positions to the other in response to an initial signal applied thereto. The preload force, at least one stiffness characteristic of the lever arms, and a compressibility of a compressible coupling element which links the second bistable element to the first, are all selected to tune signal propagation from the first bistable element to the second bistable element.

Systems and methods for micromechanical displacement-based logic circuits

The present disclosure is directed to various mechanical logic gates. In one example a mechanical logic NOT gate system is formed which has a first pair of bi-stable buckling structures each being operatively connected at a first connection point thereof to one another, and also to a first rigid structure at second connection points, the first rigid structure being held stationary. A second pair of bi-stable buckling flexures is each operatively connected at first connection points thereof to each other and at second connection points thereof to a second rigid structure being held stationary. An output element is coupled a first one of each of the first and second pairs of bi-stable buckling structures. An input element is coupled to a second one of each of the first and second pairs of bi-stable buckling structures. The output element moves from a logic 1 position to a logic 0 position in response to movement of the input element from a logic 0 position to a logic 1 positions, respectively.

Systems for mechanical logic based on additively manufacturable micro-mechanical logic gates

A flexure-based micro-array having a plurality of micro-assemblies, each comprising: an object; and at least three electrostatic actuation modules for tipping, tilting, and/or piston-actuating the object, each actuation module comprising: a base with first and second electrodes electrically isolated from each other; an electrically conductive lever arm; a first flexure bearing suspending the lever arm adjacent the first and second electrodes so that electrical activation of at least one of the first and second electrodes produces an electrostatic moment of force on the lever arm to resiliently bias the first flexure bearing and pivot the lever arm about a fulcrum; and a second flexure bearing connecting the lever arm to the object at a connection location that is different from other connection locations of the other actuation modules so that pivoting the lever arm about the fulcrum induces the second flexure bearing to pivot the object about an object pivot axis defined between two of the other connection locations while the second flexure bearing decouples the lever arm from object displacements induced by two of the other actuation modules connected to the two other connection locations defining the object pivot axis, wherein the plurality of micro-assemblies are arranged with the objects juxtaposed in a substantially 2D array.

Flexure-based, tip-tilt-piston actuation micro-array

A microarchitectured material having a plurality of interconnected unit cells in 2D or 3D configurations. The permanent interconnections to adjacent unit cells include mechanical output structures driven by mechanical actuators. One or more sensors are preferably utilized, such as utilizing a sensing mode of the actuator, for detecting forces and or displacements applied to the unit cell. The unit cells are each controlled by a control circuit for generating drive signals to the actuators in the unit cell so that desired mechanical properties and/or shapes are exhibited by the microarchitectured material.

Actively controlled microarchitectures with programmable bulk material properties

A thermal expansion-managed lattice structure having a plurality of unit cells each having flexure bearing-mounted tabs supported on a base and actuated by thermal expansion of an actuator having a thermal expansion coefficient greater than the base and arranged so that the tab is inwardly displaced into a base cavity. The flexure bearing-mounted tabs are connected to other flexure-bearing-mounted tabs of adjacent unit cells so that the adjacent unit cells are spaced from each other to accommodate thermal expansion of individual unit cells while maintaining a desired bulk thermal expansion coefficient of the lattice structure as a whole.

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Los Angeles, CA, United States of America

Jonathan Hopkins