Architected automotive impact beam
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.
1. A structural assembly comprising:
a stiff micro-truss layer including a base sheet and a micro-truss core formed thereon, where the micro-truss core comprises a 3-dimensional lattice of uniaxial micro-truss struts interconnected at nodes; and
a top sheet secured to nodes of the micro-truss core opposite to the base sheet to form a micro-truss sandwich structure.
2. The structural assembly according to claim 1 further comprising an energy absorbing micro-truss layer including the top sheet and a micro-truss core formed thereon, said energy absorbing micro-truss layer being less rigid than the stiff micro-truss layer, said structural assembly further comprising a panel secured to the micro-truss core of the energy absorbing layer opposite to the top sheet.
3. The structural assembly according to claim 2 wherein the top sheet has a different shape than the base sheet.
4. The structural assembly according to claim 2 wherein the stiff micro-truss layer and the energy absorbing micro-truss layer are both curved layers.
5. The structural assembly according to claim 4 wherein the energy absorbing micro-truss layer has a higher degree of curvature than the stiff micro-truss layer.
6. The structural assembly according to claim 2 wherein the energy absorbing micro-truss layer is less rigid than the stiff micro-truss layer because of one or more of a thickness of the layer, a diameter of the micro-truss struts, a spacing of the struts, an orientation of the struts and a material comprising the struts.
7. The structural assembly according to claim 2 wherein the top sheet is glued to the nodes of the micro-truss struts at a surface of the stiff micro-truss core.
8. The structural assembly according to claim 7 wherein the energy absorbing micro-truss layer and the stiff micro-truss layer are formed by separate micro-truss fabrication processes before they are secured together.
9. The structural assembly according to claim 1 wherein one or more of the base sheet and the top sheet are transparent at the wavelength of light used to form the micro-truss layers.
10. The structural assembly according to claim 1 wherein the base sheet and the top sheet are selected from the group consisting of thermoplastic sheets, thermoset sheets, aluminum sheets, steel sheets, glass fiber composite sheets and carbon fiber composite sheets.
11. The structural assembly according to claim 1 wherein the top sheet and the base sheet are different materials.
12. The structural assembly according to claim 1 wherein the structural assembly is a vehicle energy management bumper system.
13. The structural assembly according to claim 1 wherein the structural assembly is a vehicle side anti-intrusion bar.
14. A vehicle energy management bumper system comprising:
a curved stiff micro-truss layer including a base sheet and a micro-truss core having a 3-dimensional lattice of uniaxial polymerized struts formed thereon;
a curved energy absorbing micro-truss layer including a base sheet and a micro-truss core having a 3-dimensional lattice of uniaxial polymerized struts formed thereon, said energy absorbing micro-truss layer being less rigid than the stiff micro-truss layer and said energy absorbing layer base sheet having a different shape than the stiff layer base sheet, said energy absorbing layer base sheet being secured to the stiff micro-truss layer core opposite to the stiff layer base sheet; and
a front fascia panel secured to nodes of the energy absorbing layer micro-truss core opposite to the energy absorbing layer base sheet, where the nodes are points of interconnection between the uniaxial polymerized struts.
15. The bumper system according to claim 14 wherein the base sheets are selected from the group consisting of thermoplastic sheets, thermoset sheets aluminum sheets, steel sheets, glass fiber composite sheets, and carbon fiber composite sheets.
16. The bumper system according to claim 14 wherein the energy absorbing layer base sheet and the stiff layer base sheet are different materials.
17. The bumper system according to claim 14 wherein one or more of the energy absorbing layer base sheet and the stiff layer base sheet are transparent at the wavelength of light used to form the micro-truss layers.
18. The bumper system according to claim 14 wherein the energy absorbing micro-truss layer has a higher degree of curvature than the stiff micro-truss layer.
19. The bumper system according to claim 14 wherein the energy absorbing micro-truss layer is less rigid than the stiff micro-truss layer because of one or more of a thickness of the layer, a diameter of the uniaxial polymerized struts, a spacing of the struts, an orientation of the struts and a material comprising the struts.
20. The bumper system according to claim 14 wherein the energy absorbing base sheet is glued to the nodes of the micro-truss struts at a surface of the stiff micro-truss core.
21. The bumper system according to claim 20 wherein the energy absorbing micro-truss layer and the stiff micro-truss layer are formed by separate micro-truss fabrication processes before they are secured together.
22. A method for providing a vehicle structural assembly, said method comprising:
fabricating a stiff micro-truss layer by irradiating an enclosure filled with liquid photomonomer resin through a mask so as to form a micro-truss structure from a plurality of interconnected photopolymer waveguides secured to a base sheet;
fabricating an energy absorbing micro-truss layer by irradiating an enclosure filled with liquid photomonomer resin through a mask so as to form a micro-truss structure from a plurality of interconnected photopolymer waveguides secured to a base sheet, wherein the micro-truss structure for the energy absorbing micro-truss layer is less rigid than the stiff micro-truss layer, and the waveguides in the stiff micro-truss layer and the energy absorbing micro-truss layer form a 3-dimensional lattice of uniaxial micro-truss struts interconnected at nodes; and
securing the base sheet of the energy absorbing micro-truss layer to nodes of the micro-truss structure of the stiff micro-truss layer.
23. The method according to claim 22 further comprising securing a front fascia panel to the energy absorbing layer micro-truss structure opposite to the energy absorbing layer base sheet.
24. The method according to claim 22 wherein the energy absorbing micro-truss layer and the stiff micro-truss layer are both curved layers.