Abstract: A method and/or system for forming a micro-truss structure in an essentially arbitrary shape. A mold that has a transparent portion, and having an interior volume in the desired shape, is filled with photomonomer resin. The material for the transparent portion of the mold is selected to be a material that is index-matched to the photomonomer resin. The filled mold, placed into a bath of transparent fluid index-matched to the transparent portion of the mold, and illuminated, from outside the fluid, through a photomask, with collimated light. The collimated light travels through the photomask forming beams of light that enter the transparent fluid, propagate into the mold, and form a micro-truss structure in the shape of the interior volume of the mold. The micro-truss structure may then be removed from the mold, or part or all of the mold may be left adhered to the micro-truss structure, forming covering face sheets.

Abstract: A sparse micro-truss structure having a series of unit cells arranged in an array is disclosed. Each of the unit cells includes a series of struts interconnected at a node. Adjacent unit cells are spaced apart by a gap. Spacing apart the adjacent unit cells is configured to reduce the sensitivity of the sparse micro-truss structure to premature mechanical failure due to buckling in one or more of the struts compared to related art micro-truss structures having a series of fully interconnected unit cells.

Abstract: Ignition-quenching systems comprise an ignition-quenching cover configured to quench an ignition event in a combustible environment triggered by an ignition source associated with a fastener stack. The ignition-quenching cover comprises a porous body that is gas permeable and that has pores sized to quench ignition in the combustible environment. The ignition-quenching cover further comprises a cover attachment feature configured to mate with a fastener attachment feature of the fastener stack. The ignition-quenching cover is configured to cover the fastener stack, which may be associated with a potential ignition source that produces an ignition event in the combustible environment. The porous body may include one or more porous elements that may be formed of various polymeric, mesh, or fabric materials. The ignition-quenching cover may comprise a non-porous frame that is bonded to the porous body and that defines the cover attachment feature.

Abstract: In some variations, a polymer-based microlattice structure includes a plurality of intersecting micro-truss structural elements each comprising a thermoset first polymer, and a continuous coating layer (with a second polymer) that substantially encapsulates each of the micro-truss structural elements, wherein the second polymer in the continuous coating layer bonds the thermoset first polymer to a substrate. The micro-truss structural elements preferably are architecturally ordered and the coating layer is uniformly distributed within the microlattice structure. The polymer coating layer may be present over the entire microlattice surface area, thereby increasing bond area to improve toughness. The microlattice structure may also have higher glass-transition temperature and chemical resistance, compared to a microlattice structure without the coating layer. Methods of forming a polymer-based microlattice structure are also disclosed.

Abstract: A sandwich structure including at least one fastener attached to a first facesheet, an ordered three-dimensional microstructure core defined by a series of interconnected polymer waveguides around the at least one fastener and attached to the first facesheet, and a second facesheet attached to the ordered three-dimensional microstructure core. The ordered three-dimensional microstructure core is sandwiched between the first facesheet and the second facesheet.

Abstract: A process for fabricating a curved beam including a micro-truss structure. In one embodiment, the process includes fabricating the micro-truss structure on a bottom facesheet, where the micro-truss structure is only partially cured so that it is readily bendable, and then forming the partially cured micro-truss structure and bottom facesheet over a curved fixture, where the partially cured micro-truss structure is then fully cured and hardened to its final curved state. A top facesheet is then adhered to a top surface of the micro-truss structure. In an alternate embodiment, a curved bottom facesheet is forced flat against a fixture and the micro-truss structure is formed while the bottom facesheet is secured to the fixture to a partially cured state. The bottom facesheet is then released from the fixture, which causes it to return to its curved configuration causing the micro-truss structure to bend.

Abstract: A lightweight sandwich panel structure with a complex shape and curvature, and a method to fabricate such a panel out of high temperature alloys. Embodiments of a micro-truss core structure that offer high specific strength and stiffness while allowing for curvature, and methods for depositing multiple layers of metals that can be interdiffused into complex alloys, are provided. A core of a panel may be fabricated from a polymer template, which may be shaped, e.g., curved, and coated with metal layers, which may then be heat treated to cause the layers of metal to interdiffuse, to form an alloy.

Abstract: A lightweight sandwich panel structure with a complex shape and curvature, and a method to fabricate such a panel out of high temperature alloys. Embodiments of a micro-truss core structure that offer high specific strength and stiffness while allowing for curvature, and methods for depositing multiple layers of metals that can be interdiffused into complex alloys, are provided. A core of a panel may be fabricated from a polymer template, which may be shaped, e.g., curved, and coated with metal layers, which may then be heat treated to cause the layers of metal to interdiffuse, to form an alloy.

Abstract: A sparse micro-truss structure having a series of unit cells arranged in an array is disclosed. Each of the unit cells includes a series of struts interconnected at a node. Adjacent unit cells are spaced apart by a gap. Spacing apart the adjacent unit cells is configured to reduce the sensitivity of the sparse micro-truss structure to premature mechanical failure due to buckling in one or more of the struts compared to related art micro-truss structures having a series of fully interconnected unit cells.

Abstract: A hierarchical sandwich box impact beam for a vehicle that includes spaced apart micro-truss sandwich structures defining an open area therebetween. The impact beam includes an outer facing sandwich structure including an outer facesheet, an inner facesheet and a micro-truss core formed therebetween, and an inner facing sandwich structure including an outer facesheet, an inner facesheet and a micro-truss core formed therebetween. One or more structural connecting sections are coupled to the inner and outer facing sandwich structures so as to define the open area between the structures.

Abstract: Methods of embedding at least one fastener in a sandwich structure having an ordered three-dimensional microstructure core provided between a pair of facesheets. The method includes attaching the at least one fastener to a first facesheet. The method also includes irradiating a volume of photo-monomer in a reservoir with light beams to form an ordered three-dimensional microstructure core around the at least one fastener. The method also includes attaching a second facesheet to the ordered three-dimensional microstructure core to form the sandwich structure. The fasteners embedded in the sandwich structure are configured to facilitate attachment of the sandwich structure to another structure.

Abstract: Methods of embedding at least one fastener in a sandwich structure having an ordered three-dimensional microstructure core provided between a pair of facesheets. The method includes attaching the at least one fastener to a first facesheet. The method also includes irradiating a volume of photo-monomer in a reservoir with light beams to form an ordered three-dimensional microstructure core around the at least one fastener. The method also includes attaching a second facesheet to the ordered three-dimensional microstructure core to form the sandwich structure. The fasteners embedded in the sandwich structure are configured to facilitate attachment of the sandwich structure to another structure.

Abstract: A curved sandwich impact structure for a vehicle having a micro-truss core. In one embodiment, the sandwich impact structure includes a micro-truss layer sandwiched between two facesheets, a micro-truss layer designed for energy absorption on the outside of one of the facesheets, and a fascia panel in contact with the energy absorbing micro-truss layer.

Abstract: A sandwich material having both structural strength and significant acoustic attenuation. In one embodiment, a sandwich is composed of an architected core secured between two facesheets, with a compliant layer forming the connection between the core and the facesheets. The compliant core has a low modulus, resulting in a low speed for elastic shear waves in the sandwich, at low static loads. At high static loads the compliant material stiffens and allows the sandwich to exhibit significant structural strength.

Abstract: A method for fabricating a sandwich box impact beam for a vehicle. The method includes fabricating inner and outer facing sandwich structures each including an inner facesheet, an outer facesheet and a micro-truss core therebetween. The micro-truss cores are an ordered three-dimensional network of self-propagating polymer waveguides grown from a photo-monomer resin using a controlled exposure to collimated UV light sources at specified orientations through a plurality of apertures in a mask. The method includes mounting the inner and outer sandwich structures so that an open area is provided therebetween where the inner facesheets face each other across the open area.

Abstract: A hierarchical sandwich box impact beam for a vehicle that includes spaced apart micro-truss sandwich structures defining an open area therebetween. The impact beam includes an outer facing sandwich structure including an outer facesheet, an inner facesheet and a micro-truss core formed therebetween, and an inner facing sandwich structure including an outer facesheet, an inner facesheet and a micro-truss core formed therebetween. One or more structural connecting sections are coupled to the inner and outer facing sandwich structures so as to define the open area between the structures.

Abstract: A sandwich material having both structural strength and significant acoustic attenuation. In one embodiment, a sandwich is composed of an architected core secured between two facesheets, with a compliant layer forming the connection between the core and the facesheets. The compliant core has a low modulus, resulting in a low speed for elastic shear waves in the sandwich, at low static loads. At high static loads the compliant material stiffens and allows the sandwich to exhibit significant structural strength.

Abstract: A composition for forming a microlattice structure includes a photopolymerizable compound and a flame retardant material. A microlattice structure includes a plurality of struts interconnected at a plurality of nodes, the struts including: a copolymer including a reaction product of a photopolymerizable compound and a flame retardant material. A microlattice structure includes a plurality of struts interconnected at a plurality of nodes, the struts including: a polymer including a reaction product of a photopolymerizable compound; and a flame retardant material.

Abstract: A curved sandwich impact structure for a vehicle having a micro-truss core. In one embodiment, the sandwich impact structure includes a micro-truss layer sandwiched between two facesheets, a micro-truss layer designed for energy absorption on the outside of one of the facesheets, and a fascia panel in contact with the energy absorbing micro-truss layer.

Abstract: A process for fabricating a curved beam including a micro-truss structure. In one embodiment, the process includes fabricating the micro-truss structure on a bottom facesheet, where the micro-truss structure is only partially cured so that it is readily bendable, and then forming the partially cured micro-truss structure and bottom facesheet over a curved fixture, where the partially cured micro-truss structure is then fully cured and hardened to its final curved state. A top facesheet is then adhered to a top surface of the micro-truss structure. In an alternate embodiment, a curved bottom facesheet is forced flat against a fixture and the micro-truss structure is formed while the bottom facesheet is secured to the fixture to a partially cured state. The bottom facesheet is then released from the fixture, which causes it to return to its curved configuration causing the micro-truss structure to bend.