Method of fabricating a three-dimensionally patterned mechanical energy absorptive material

Abstract

A three-dimensionally patterned energy absorptive material and fabrication method having multiple layers of patterned filaments extrusion-formed from a curable pre-cursor material and stacked and cured in a three-dimensionally patterned architecture so that the energy absorptive material produced thereby has an engineered bulk property associated with the three-dimensionally patterned architecture.

Claims

1. A method of fabricating a three-dimensionally patterned mechanical energy absorptive material comprising: extrusion-forming from a pre-cursor material multiple layers of patterned elastomeric filaments stacked on a substrate so that elastomeric filaments of a first elastomeric filament layer are formed with a predetermined spacing from each other and in direct contact with and in a predetermined transverse orientation relative to elastomeric filaments of an adjacent elastomeric filament layer which are formed with a predetermined spacing from each other; and simultaneously curing the stacked multiple layers of patterned elastomeric filaments so that elastomeric filaments of a first elastomeric filament layer are directly bonded to elastomeric filaments of an adjacent elastomeric filament layer, and the mechanical energy absorptive material has a pre-determined bulk property profile that absorbs mechanical energy with a pre-determined mechanical response.

2. The method of claim 1, wherein the filaments are arranged so that the three-dimensionally patterned mechanical energy absorptive material comprises at least one of open-cells and closed cells between filaments.

3. The method of claim 1, wherein the filaments are patterned so that the predetermined bulk property profile of the mechanical energy absorptive material is uniform in at least one direction across different regions of the mechanical energy absorptive material.

4. The method of claim 1, wherein the filaments are patterned so that the pre-determined bulk property profile of the mechanical energy absorptive material is different for different regions of the mechanical energy absorptive material.

5. The method of claim 4, wherein the filaments are patterned so that the pre-determined bulk property profile of the mechanical energy absorptive material is graded across the different regions of the mechanical energy absorptive material along at least one direction.

6. The method of claim 1, wherein the substrate surface is non-planar so that the mechanical energy absorptive material formed thereon also has a non-planar contour.

7. The method of claim 6, wherein the substrate surface is contoured substantially similar to a 3D object against which mechanical energy is to be absorbed by the mechanical energy absorptive material so that the mechanical energy absorptive material formed on the substrate substantially conforms to said 3D object.

8. A method of fabricating a three-dimensionally patterned mechanical energy absorptive material comprising: extrusion-forming a first elastomeric filament layer by extruding patterned elastomeric filaments of a curable pre-cursor material on a substrate; extrusion-forming a second elastomeric filament layer by extruding patterned elastomeric filaments of the curable pre-cursor material on the elastomeric filaments of the first elastomeric filament layer so that the elastomeric filaments of the second elastomeric filament layer are formed with a predetermined spacing from each other and in direct contact with, in a predetermined transverse orientation relative to, and supported by the elastomeric filaments of the first elastomeric filament layer which are formed with a predetermined spacing from each other; and simultaneously curing the elastomeric filament layers so that the elastomeric filaments of the first elastomeric filament layer are directly bonded to the elastomeric filaments of the second elastomeric filament layer, and the mechanical energy absorptive material has a pre-determined bulk property profile that absorbs mechanical energy with a pre-determined mechanical response.

9. The method of claim 8, further comprising extrusion-forming at least one additional filament layer on the second filament layer prior to curing so that the filaments of each additional layer are in direct contact with and supported by the filaments of an adjacent underyling filament layer; and wherein the simultaneously curing step simultaneously cures all the filament layers so that the filaments of each filament layer are directly bonded to the filaments of an adjacent filament layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The accompanying drawings, where are incorporated into and forma a part of the disclosure, are as follows:

(2) FIG. 1 is a flow diagram of an exemplary embodiment of the method of fabricating a three-dimensionally patterned energy absorptive material of the present invention.

(3) FIG. 2 is an exploded perspective view of various filament layers patterned layer-by-layer into a three-dimensionality patterned architecture of an exemplary embodiment of the energy absorptive material of the present invention.

(4) FIG. 3 is a top view of another exemplary embodiment of the energy absorptive material of the present invention.

(5) FIG. 4 is a cross-sectional view of another example embodiment of the energy absorptive material of the present invention 40, having five representative filament layers, and an offset alignment of filaments

(6) FIG. 5 is a cross-sectional view following FIG. 4 after being compressed.

(7) FIG. 6 is a cross-sectional view of another example embodiment of the energy absorptive material of the present invention 50 with a vertically aligned stacked arrangement of filaments.

(8) FIG. 7 is a cross-sectional view following FIG. 6 after being compressed.

(9) FIG. 8 is a cross-sectional view of another exemplary embodiment of the present invention fabricated on a non-planar substrate.

DETAILED DESCRIPTION

(10) Turning now to the drawings, FIG. 1 shows a generalized flow chart of an example method of fabricating the three-dimensionally patterned energy absorptive material of the present invention. In particular at 10, a first layer of filaments is extrusion-formed, such as by direct ink write (DIW) and patterned on a substrate using a curable precursor material. Extrusion-forming may be performed using an extrusion printer (not shown) capable of precision patterning the precursor material (e.g. siloxane resin). In particular, the printhead (or nozzle) may consist of a single- or multiple nozzle configuration. Furthermore, printing may occur on planar or nonplanar substrates, and may be done in serial (i.e. one filament at a time) or in parallel (multiple filaments at a time). Printing may also be performed in a roll-to-roll fashion.

(11) Next at block 11, one or more additional layer or layers of filaments are extrusion-formed and patterned layer-by-layer to form a three-dimensionally (3D) patterned architecture associated with a desired bulk property of the energy absorptive material. The bulk properties for a given 3D patterned architecture may be determined, for example, by computer modeling as described in the Summary.

(12) At block 12, the filament layers are then cured (e.g. via gelation and/or a chemical curing mechanism) to solidify the form the energy absorptive material having the desired bulk property associated with the 3D patterned architecture. It is appreciated that curing may be performed altogether at the completion of printing, or may be progressively cured in situ, depending on the type of pre-cursor or constituent material used.

(13) At block 13, the solidified energy absorptive material is then removed from the substrate upon which it is fabricated. It is appreciated in the alternative that the energy absorptive material may be kept together with the substrate, such as for example, where the substrate functions as a backplate.

(14) FIG. 2 shows an exploded perspective view of various filament layers patterned layer-by-layer into a three-dimensionally patterned architecture of an exemplary embodiment of the energy absorptive material of the present invention. A first layer of patterned filaments 20 is shown as a single continuously extrusion-formed filament that switches back and forth across a substrate (not shown) in a controlled pattern to form multiple filament segments such as 26 arranged substantially parallel with each other, and with predetermined filaments features, including filament cross-sectional shape and width, spacing between filaments, and length per switchback segment. As shown, the first layer of patterned filaments begins at point A and ends at point B. It is appreciated that while the first layer is formed as a single continuously extrusion-formed filament, the filament segments may be individually formed as a discrete segment.

(15) A second layer of patterned filaments 21 is shown formed on the first layer 20 in a similar manner as for the first layer, as a single continuously extrusion-formed filament beginning at point C and ending at point D. Furthermore, third and fourth layers of patterned filaments 22 and 23, respectively, are also shown similarly formed as single continuously extrusion-formed filaments, with the third layer 22 starting at point F and ending at point E, and the fourth layer 23 starting at point G and ending at point H. A print head 24 of a direct write ink system is shown having a nozzle 25 from which the precursor material is extruded from. While each of the filament layers may be independently formed in a layer-by-layer process separate and apart from the other layers, the three-dimensionally patterned architecture of the multiple layers may be formed in the alternative as a single continuously extrusion-formed filament by connecting points B and C between the first and second layers, connecting points D and E between the second and third layers, and connecting F and G between the third and fourth layers.

(16) FIG. 3 shows a top view of another exemplary embodiment of the energy absorptive material of the present invention, generally indicated at 30. Three layers are shown having filaments patterned generally transverse to each other. In particular the filament layer defined between points 31 and 32 have filament segments that are orthogonally oriented with respect to the filament segments of the filament layer defined between points 33 and 34. And a third filament layer defined between points 35 and 36 is shown transversely arranged at a substantially 45 degree angle to the two previous filament layers. The 3D patterned architecture 30 of FIG. 3 is only one illustrative arrangement of filament layers relative to each other, with other architectures having different stacked arrangements.

(17) FIG. 4 shows a cross-sectional view of another example embodiment of the energy absorptive material of the present invention 40, having five representative filament layers represented by filaments 41 for the first layer, filaments 42 for the second layer, filaments 43 for the third layer, filaments 44 for the fourth layer and filaments 45 for the fifth layer. As shown the filament layers having filaments arrangement substantially parallel to each other (e.g. layers represented by 41, 43 and 45) are arranged such that alternating layers have filaments that are offset from each other. As such, filaments 43 are offset from filaments 41 and 45, while filaments 41 and 45 are shown arranged in a vertically stacked arrangement. As shown in FIG. 5, this example stacking arrangement of the 3D patterned architecture of FIG. 4, when compressed, has a certain bulk property (e.g. compression strength) that is determined by and associated with the particular 3D patterned architecture. As such, in FIG. 5, the offset arrangement of filaments 43 function to contort both adjacent filament layers (represented by filaments 42 and 43). Pores are also formed between the filaments, with pore dimensions and properties determined by spacing and other positioning of the filaments.

(18) In comparison to FIGS. 4 and 5, FIGS. 6 and 7 shown an alternative example embodiment of the energy absorptive material of the present invention generally indicated at 50, having a different stacked arrangement of filaments and thus a different 3D patterned architecture. As shown in FIGS. 6 and 7, eight representative filament layers 1-8 are shown, represented by filaments 51 to 58, respectively. In this architecture, the filaments of alternating layers (e.g. 52, 54, 56 and 58) are vertically aligned such that compression strength is increased due to the vertical support provided by the stacked filaments. In this regard, it is appreciated that filament properties and spacing may be engineered to tailor the filament density, to produce a 3D patterned architecture having a bulk property that is associated with and attributable to its architecture. The filaments may also be arranged (e.g. spaced) so that the desired property is uniform throughout said material. In the alternative, the filaments may be arranged so that the desired property is different for different regions of said material. As such, in the material and fabrication method of the present invention structure and properties may be uniform or graded. For example, a part may have uniform or graded compressive strength over a given distance. If uniform, then the energy can be dissipated isotropically. And if graded, then the energy can be dissipated directionally. It is also appreciated that the 3D patterned architecture may be formed with at least one of open cells, closed cells, or some open and some closed cells, which may be determined again by the particular spacing and arrangement of the filaments.

(19) And FIG. 8 shows another example embodiment of the present invention 60 where the multiple layers of filaments, represented by filaments 62-65, are extrusion-formed on a non-planar substrate 61 so that the energy absorptive material formed on the substrate is also shaped with a non-planar surface contour. In particular, the non-planar substrate may be used to outline a three-dimensional object against which the fabricated material is intended to absorb/dissipate energy from, so that the material may substantially conform to the 3D object. And after fabrication, the material 60 may be removed from the substrate, or kept on the substrate for use with the substrate, such as for example, as a backplate.

(20) Although the description above contains many details and specifics, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Other implementations, enhancements and variations can be made based on what is described and illustrated in this patent document. The features of the embodiments described herein may be combined in all possible combinations of methods, apparatus, modules, systems, and computer program products. Certain features that are described in this patent document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments.

(21) Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art. In the claims, reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural and functional equivalents to the elements of the above-described preferred embodiment that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. Moreover, it is not necessary for a device to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element or component in the present disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.”