Abstract: A valve for a pneumatic system, has: a first enclosure defining a first chamber and a first connection port; a second enclosure defining a second chamber and a second connection port; a first shell subjected to a first pressure differential and movable from a default position to a reversed position via snap-through buckling upon the first pressure differential reaching a threshold; and a second shell having a shape different than a shape of the first shell, the second shell resiliently movable from an initial position to a deformed position when subjected to a second pressure differential, wherein a first flow rate of a fluid via the first connection port induces deformation of the second shell followed by a snapping of the first shell thereby generating a second flow rate greater than the first flow rate.

Abstract: A valve for a pneumatic system, has: a first enclosure defining a first chamber and a first connection port; a second enclosure defining a second chamber and a second connection port; a first shell subjected to a first pressure differential and movable from a default position to a reversed position via snap-through buckling upon the first pressure differential reaching a threshold; and a second shell having a shape different than a shape of the first shell, the second shell resiliently movable from an initial position to a deformed position when subjected to a second pressure differential, wherein a first flow rate of a fluid via the first connection port induces deformation of the second shell followed by a snapping of the first shell thereby generating a second flow rate greater than the first flow rate.

Abstract: A methodology integrating multiscale analysis and design optimization to design a novel bone replacement implant made of a functionally graded cellular material that meets fatigue requirements imposed by cyclic loadings. The pore microarchitecture, described by interconnectivity, porosity, pore size as well as pore topology, is optimally designed for tissue regeneration and mechanical strength. A bone implant with a graded cellular microstructure is also provided.

Abstract: A method for manufacturing an implant includes pre-selecting a designed porous microstructure having a lattice composed of cells, including selecting one or more predetermined cell topologies, selecting a predetermined porosity, cell strut thickness and packing factor of the lattice, and selecting an arrangement of the cells within the lattice to have a periodic and/or aperiodic arrangement. Additive manufacturing is used to form the designed porous lattice microstructure in at least a region of at least an external surface of the implant.

Abstract: A metamaterial having a programmed thermal expansion when exposed to a temperature condition is described. The metamaterial includes a lattice structure composed of a plurality of interconnected unit cells, each of the unit cells comprising two or more bi-material building blocks having first material elements and second material elements. The first material elements have a first coefficient of thermal expansion (CTE) and the second material elements having a second CTE, the first CTE being greater than the second CTE. The bi-material building blocks have a topology with two or more vertices formed at junctions between said first material elements and said second material elements. One of the first material elements interconnects and extends between two of the second material elements at the vertices. The first material elements deforming substantially long a longitudinal axis thereof to cause the bi-material building blocks to be stretch-dominated when deforming in response to temperature changes.

Abstract: An implant comprising a porous microstructure is disclosed which has an external surface, where at least a region of the external surface is formed of the porous microstructure. The microstructure is defined by at least one lattice of cells. Each cell has a predetermined cell topology and a plurality of edges. One or more of the edges of each cell connect to an adjacent cell along a corresponding edge thereof. Collectively, the cells have a periodic or aperiodic arrangement within the at least one lattice.

Abstract: A methodology integrating muitiscale analysis and design optimization to design a novel bone replacement implant made of a functionally graded cellular material that meets fatigue requirements imposed by cyclic loadings. The pore microarchitecture, described by interconnectivity, porosity, pore size as well as pore topology, is optimally designed for tissue regeneration and mechanical strength. The method can contribute to the development of a new generation of bone replacement implants with a graded cellular microstructure.

Abstract: An auxetic metamaterial including a plurality of interconnected building blocks that are deformable between a collapsed position and an expanded position upon the application of a load. The building blocks are bistable, and define a stable state in both the collapsed position and the expanded position. In the stable state, the building blocks maintain the collapsed position or the expanded position, even after removal of the load applied on the building block.

Abstract: A metamaterial reversibly deformable when exposed to a temperature condition, has metaunits interconnected with one another to form a metaensemble. The metaunits include frames and cores attached to the frames, portions of the cores being free of connection with the frames. One of the frame and the core having a Young's modulus greater than that of the other and having a coefficient of thermal expansion less than that of the other. The metaensemble having a sequence code defining a target shape of the metaensemble, the sequence code including at least one geometric characteristic and at least one material characteristic of each of the frame and the core. The metamaterial with the sequence code being reversibly deformable from an initial shape to the target shape upon being exposed to the temperature condition, and back from the target shape to the initial shape upon withdrawal of the temperature condition.

Abstract: An auxetic metamaterial including a plurality of interconnected building blocks that are deformable between a collapsed position and an expanded position upon the application of a load. The building blocks are bistable, and define a stable state in both the collapsed position and the expanded position. In the stable state, the building blocks maintain the collapsed position or the expanded position, even after removal of the load applied on the building block.

Abstract: An implant comprising a porous microstructure is disclosed which has an external surface, where at least a region of the external surface is formed of the porous microstructure. The microstructure is defined by at least one lattice of cells. Each cell has a predetermined cell topology and a plurality of edges. One or more of the edges of each cell connect to an adjacent cell along a corresponding edge thereof. Collectively, the cells have a periodic or aperiodic arrangement within the at least one lattice.

Abstract: A method for generating a lattice cell shape for a stent comprising generating a unit cell model representing a stent cell to be made of a given material, the unit cell model comprising elements each comprising points defining a G2-continuous curve, setting a weighting factor to a same value for each one of the points, the weighting factor representing a contribution of a corresponding one of the points to a curvature of an optimal curve, determining a curvature of the G2-continuous curve as a function of the weighting factors having the same value, and structurally optimizing the unit cell model by iteratively determining a variable value for the weighting factor value using stress-strain characteristics for the given material, determining a new curvature of the G2-continuous curve as a function of the variable value, and minimizing the new curvature, thereby obtaining an optimized curve corresponding to an optimized lattice cell shape.

Abstract: A methodology integrating multiscale analysis and design optimization to design a novel bone replacement implant made of a functionally graded cellular material that meets fatigue requirements imposed by cyclic loadings. The pore microarchitecture, described by interconnectivity, porosity, pore size as well as pore topology, is optimally designed for tissue regeneration and mechanical strength. The method can contribute to the development of a new generation of bone replacement implants with a graded cellular microstructure.

Abstract: A method for generating a lattice cell shape for a stent comprising generating a unit cell model representing a stent cell to be made of a given material, the unit cell model comprising elements each comprising points defining a G2-continuous curve, setting a weighting factor to a same value for each one of the points, the weighting factor representing a contribution of a corresponding one of the points to a curvature of an optimal curve, determining a curvature of the G2-continuous curve as a function of the weighting factors having the same value, and structurally optimizing the unit cell model by iteratively determining a variable value for the weighting factor value using stress-strain characteristics for the given material, determining a new curvature of the G2-continuous curve as a function of the variable value, and minimizing the new curvature, thereby obtaining an optimized curve corresponding to an optimized lattice cell shape.