具体实施方式：
[0125]It is to be expressly understood that the description and drawings are only for purposes of illustrating certain embodiments and are an aid for understanding. They are not intended to be and should not be limiting.
DETAILED DESCRIPTION OF EMBODIMENTS
[0126]FIGS. 1 to 4 show an embodiment of an article 10 (e.g., a device or other functional article) comprising additively-manufactured components 121-12A. in accordance with an embodiment of the present disclosure.
[0127]Each of the additively-manufactured components 121-12A of the article 10 is a part of the article 10 that is additively manufactured, i.e., made by additive manufacturing, also known as 3D printing, in which material 50 thereof initially provided as feedstock (e.g., powder, liquid, filaments, fibers, and/or other suitable feedstock), which can be referred to as 3D-printed material 50, is added by a machine (i.e., a 3D printer) that is computer-controlled (e.g., using a digital 3D model such as a computer-aided design (CAD) model that may have been generated by a 3D scan of the intended wearer's head) to create it in its three-dimensional form (e.g., layer by layer, or by continuous liquid interface production from a pool of liquid, or by applying continuous fibers, or in any other way, normally moldlessly, i.e., without any mold). This is in contrast to subtractive manufacturing (e.g., machining) where material is removed and molding where material is introduced into a mold's cavity.
[0128]Any 3D-printing technology may be used to make the additively-manufactured components 121-12A of the article 10. For instance, in some embodiments, one or more of the following additive manufacturing technologies may be used individually or in combination: material extrusion technologies, such as fused deposition modeling (FDM); vat photopolymerization technologies, such as stereolithography (SLA), digital light processing (DLP), continuous digital light processing (CDLP) or continuous liquid interface production (CLIP) with digital light synthesis (DLS); powder bed fusion technologies, such as multi-jet fusion (MJF), selective laser sintering (SLS), direct metal laser sintering/selective laser melting (DMLS/SLM), or electron beam melting (EBM); material jetting technologies, such as material jetting (MJ), nanoparticle jetting (NPJ) or drop on demand (DOD); binder jetting (BJ) technologies; sheet lamination technologies, such as laminated object manufacturing (LOM); material extrusion technologies, such as continuous-fiber 3D printing or fused deposition modeling (FDM), and/or any other suitable 3D-printing technology. Non-limiting examples of suitable 3D-printing technologies may include those available from Carbon (www.carbon3d.com), EOS (https://www.eos.info/en), HP (https://www8.hp.com/ca/en/printers/3d-printers.html), Arevo (https://arevo.com), and Continuous Composites (https://www.continuouscomposites.com/).
[0129]As further discussed later, in this embodiment, the additively-manufactured components 121-12A of the article 10, which may be referred to as “AM” components, are designed to enhance performance and use of the article 10, such as: impact protection, including for managing different types of impacts; fit and comfort; adjustability; and/or other aspects of the article 10.
[0130]In this embodiment, the article 10 is an article of equipment usable by a user. More particularly, in this embodiment, the article 10 is an article of athletic gear for the user who is engaging in a sport or other athletic activity. Specifically, in this embodiment, the article of athletic gear 10 is an article of protective athletic gear wearable by the user to protect him/her. More specifically, in this example, the article of protective athletic gear 10 is a helmet for protecting a head of the user against impacts. In this case, the helmet 10 is a hockey helmet for protecting the head of the user, who is a hockey player, against impacts (e.g., from a puck or ball, a hockey stick, a board, ice or another playing surface, etc., with another player, etc.).
[0131]More particularly, in this embodiment, the helmet 10 comprises an outer shell 11 and a liner 15 to protect the player's head. In this example, the helmet 10 also comprises a chinstrap 16 for securing the helmet 10 to the player's head. The helmet 10 may also comprise a faceguard 14 (as shown in FIGS. 5 and 6) to protect at least part of the player's face (e.g., a grid (sometimes referred to as a “cage”) and a chin cup 112 as shown in FIG. 5 or a visor (sometimes referred to as a “shield”) as shown in FIG. 6).
[0132]The helmet 10 defines a cavity 13 for receiving the player's head. In response to an impact, the helmet 10 absorbs energy from the impact to protect the player's head. The helmet 10 protects various regions of the player's head. As shown in FIGS. 7 and 8, the player's head comprises a front region FR, a top region TR, left and right side regions LS, RS, a back region BR, and an occipital region OR. The front region FR includes a forehead and a front top part of the player's head and generally corresponds to a frontal bone region of the player's head. The left and right side regions LS, RS are approximately located above the player's ears. The back region BR is opposite the front region FR and includes a rear upper part of the player's head. The occipital region OR substantially corresponds to a region around and under the head's occipital protuberance.
[0133]The helmet 10 comprises an external surface 18 and an internal surface 20 that contacts the player's head when the helmet 10 is worn. The helmet 10 has a front-back axis FBA, a left-right axis LRA, and a vertical axis VA which are respectively generally parallel to a dorsoventral axis, a dextrosinistral axis, and a cephalocaudal axis of the player when the helmet 10 is worn and which respectively define a front-back direction, a lateral direction, and a vertical direction of the helmet 10. Since they are generally oriented longitudinally and transversally of the helmet 10, the front-back axis FBA and the left-right axis LRA can also be referred to as a longitudinal axis and a transversal axis, respectively, while the front-back direction and the lateral direction can also be referred to a longitudinal direction and a transversal direction, respectfully.
[0134]The outer shell 11 provides strength and rigidity to the helmet 10. To that end, the outer shell 11 typically comprises a rigid material 27. For example, in various embodiments, the rigid material 27 of the outer shell 11 may be a thermoplastic material such as polyethylene (PE), polyamide (nylon), or polycarbonate, a thermosetting resin, or any other suitable material. The outer shell 11 includes an inner surface 17 facing the inner liner 15 and an outer surface 19 opposite the inner surface 17. The outer surface 19 of the outer shell 11 constitutes at least part of the external surface 18 of the helmet 10. In some embodiments, the outer shell 11 or at least portions thereof may be manufactured via additive manufacturing and portions thereof may have differing properties. For example, portions of the outer shell 11 may be additively manufactured such that they differ in terms of rigidity (e.g., to save on weight in areas of the helmet in which rigidity is less crucial and/or to intentionally provide flexibility in certain areas of the shell in order to provide impact cushioning via the shell).
[0135]In this embodiment, the outer shell 11 comprises shell members 22, 24 that are connected to one another. In this example, the shell member 22 comprises a top portion 21 for facing at least part of the top region TR of the player's head, a front portion 23 for facing at least part of the front region FR of the player's head, and left and right lateral side portions 25L, 25R extending rearwardly from the front portion 23 for facing at least part of the left and right side regions LS, RS of the player's head, respectively. The shell member 24 comprises a top portion 29 for facing at least part of the top region TR of the player's head, a back portion 31 for facing at least part of the back region BR of the player's head, an occipital portion 33 for facing at least part of the occipital region OR of the player's head, and left and right lateral side portions 35L, 35R extending forwardly from the back portion 31 for facing at least part of the left and right side regions LS, RS of the player's head, respectively.
[0136]In this embodiment, the helmet 10 is adjustable to adjust how it fits on the player's head. To that end, the helmet 10 comprises an adjustment mechanism 40 for adjusting a fit of the helmet 10 on the player's head. The adjustment mechanism 40 may allow the fit of the helmet 10 to be adjusted by adjusting one or more internal dimensions of the cavity 13 of the helmet 10, such as a front-back internal dimension FBD of the cavity 13 in the front-back direction of the helmet 10 and/or a left-right internal dimension LRD of the cavity 13 in the left-right direction of the helmet 10, as shown in FIG. 9.
[0137]More particularly, in this embodiment, the adjustment mechanism 40 is configured such that the outer shell 11 and the inner liner 15 are adjustable to adjust the fit of the helmet 10 on the player's head. To that end, in this embodiment, the shell members 22, 24 are movable relative to one another to adjust the fit of the helmet 10 on the player's head. In this example, relative movement of the shell members 22, 24 for adjustment purposes is in the front-back direction of the helmet 10 such that the front-back internal dimension FBD of the cavity 13 of the helmet 10 is adjusted. This is shown in FIGS. 10 to 13 in which the shell member 24 is moved relative to the shell member 22 from a first position, which is shown in FIG. 10 and which corresponds to a minimum size of the helmet 10, to a second position, which is shown in FIG. 11 and which corresponds to an intermediate size of the helmet 10, and to a third position, which is shown in FIGS. 12 and 13 and which corresponds to a maximum size of the helmet 10.
[0138]In this example of implementation, the adjustment mechanism 40 comprises an actuator 41 that can be moved (in this case pivoted) by the player between a locked position, in which the actuator 41 engages a locking part 45 (as best shown in FIGS. 14 and 15) of the shell member 22 and thereby locks the shell members 22, 24 relative to one another, and a release position, in which the actuator 41 is disengaged from the locking part 45 of the shell member 22 and thereby permits the shell members 22, 24 to move relative to one another so as to adjust the size of the helmet 10. The adjustment mechanism 40 may be implemented in any other suitably way in other embodiments.
[0139]For instance, in some cases, the shock-absorbing material may include a polymeric foam (e.g., expanded polypropylene (EPP) foam, expanded polyethylene (EPE) foam, expanded polymeric microspheres (e.g., Expancel™ microspheres commercialized by Akzo Nobel), or any other suitable polymeric foam material) and/or a polymeric structure comprising one or more polymeric materials. Any other material with suitable impact energy absorption may be used in other embodiments. For example, in some embodiments, the shock-absorbing material may include liquid crystal elastomer (LCE) components, as discussed in further detail later on with reference to FIGS. 46 to 48. Additionally or alternatively, in some embodiments, the inner liner 15 may comprise an array of shock absorbers that are configured to deform when the helmet 10 is impacted. For instance, in some cases, the array of shock absorbers may include an array of compressible cells that can compress when the helmet 10 is impacted. Examples of this are described in U.S. Pat. No. 7,677,538 and U.S. Patent Application Publication 2010/0258988, which are incorporated by reference herein.
[0140]The liner 15 may be connected to the outer shell 11 in any suitable way. For example, in some embodiments, the inner liner 15 may be fastened to the outer shell 11 by one or more fasteners such as mechanical fasteners (e.g., tacks, staples, rivets, screws, stitches, etc.), an adhesive, or any other suitable fastener. In some embodiments, the liner 15 and/or the outer shell 11 may be manufactured via additive manufacturing such that they incorporate corresponding mating elements that are configured to securely engage one another, potentially without the need for other fastening means to fasten the liner 15 to the outer shell 11. In other embodiments, at least a portion of the liner 15 and at least a portion of the outer shell 11 may be additively manufactured as a unitary structure. For example, a rear portion of the liner 15 may be additively-manufactured together with the rear shell member 24 and/or a front portion of the liner 15 may be additively-manufactured together with the front portion 23 of the front shell member 22.
[0141]In this embodiment, the liner 15 comprises a plurality of pads 361-36A, 371-37C disposed between the outer shell 11 and the player's head when the helmet 10 is worn. In this example, respective ones of the pads 361-36A, 371-37C are movable relative to one another and with the shell members 22, 24 to allow adjustment of the fit of the helmet 10 using the adjustment mechanism 40.
[0142]In this example, the pads 361-36A are responsible for absorbing at least a bulk of the impact energy transmitted to the inner liner 15 when the helmet 10 is impacted and can therefore be referred to as “absorption” pads. In this embodiment, the pad 361 is for facing at least part of the front region FR and left side region LS of the player's head, the pad 362 is for facing at least part of the front region FR and right side region RS of the player's head, the pad 363 is for facing at least part of the back region BR and left side region LS of the player's head, the pad 364 is for facing at least part of the back region BR and right side region RS of the player's head. Another pad, (not shown in FIGS. 16 to 20) is for facing at least part of the top region TR and back region BR of the player's head. The shell member 22 overlays the pads 361, 362 while the shell member 24 overlays the pads 363, 364.
[0143]In this embodiment, the pads 371-37C are responsible to provide comfort to the player's head and can therefore be referred to as “comfort” pads. The comfort pads 371-37C may comprise any suitable soft material providing comfort to the player. For example, in some embodiments, the comfort pads 371-37C may comprise polymeric foam such as polyvinyl chloride (PVC) foam, polyurethane foam (e.g., PORON XRD foam commercialized by Rogers Corporation), vinyl nitrile foam or any other suitable polymeric foam material and/or a polymeric structure comprising one or more polymeric materials. In some embodiments, given ones of the comfort pads 371-37C may be secured (e.g., adhered, fastened, etc.) to respective ones of the absorption pads 361-36A. In other embodiments, given ones of the comfort pads 371-37C may be mounted such that they are movable relative to the absorption pads 361-36A. For example, in some embodiments, one or more of the comfort pads 371-37C may be part of a floating liner as described in U.S. Patent Application Publication 2013/0025032, which, for instance, may be implemented as the SUSPEND-TECH™ liner member found in the BAUER™ RE-AKT™ and RE-AKT 100™ helmets made available by Bauer Hockey, Inc. The comfort pads 371-37C may assist in absorption of energy from impacts, in particular, low-energy impacts.
[0144]In this embodiment, the liner 15 comprises respective ones of the AM components 121-12A of the helmet 10. More particularly, in this embodiment, respective ones of the pads 361-36A comprise respective ones of the AM components 121-12A of the helmet 10. In some embodiments, one or more other components of the helmet 10, such as the outer shell 11, comfort pads 371-37C, face guard 14 and/or chin cup 112 may also or instead be AM components.
[0145]A pad 36X comprising an AM component 12X of the helmet 10 may be configured to enhance performance and use of the helmet 10, such as: impact protection, including for managing different types of impacts; fit and comfort; adjustability; and/or other aspects of the helmet 10.
[0146]For example, in some embodiments, the AM component 12X comprised by the pad 36X may be configured to provide multi-impact protection for repeated and different types of impacts, including linear and rotational impacts, which may be at different energy levels, such as high-energy, mid-energy, and low-energy impacts, as experienced during hockey.
[0147]The AM component 12X comprised by the pad 36X may provide such multi-impact protection while remaining relatively thin, i.e., a thickness Tc of the AM component 12X comprised by the pad 36X is relatively small, so that a thickness Th of the helmet 10 at the AM component 12X, which can be referred to as an “offset” of the helmet 10 at that location, is relatively small.
[0148]As an example, in some embodiments, at least part of the AM component 12X comprised by the pad 36X may be disposed in a given one of the lateral side portions 25L, 25R of the helmet 10 and the thickness Tc of the AM component 12X comprised by the pad 36X at that given one of the lateral side portions 25L, 25R of the helmet 10 may be no more than 22 mm, in some cases no more than 20 mm, in some cases no more than 18 mm, and in some cases no more than 16 mm (e.g., 15 mm or less). This may allow the offset of the helmet 10 at the lateral side portions 25L, 25R of the helmet 10 to be small, which may be highly desirable.
[0149]In other examples, in some embodiments, at least part of the AM component 12X comprised by the pad 36X may be disposed in a given one of the front portion 23 and the back portion 31 of the helmet 10 and the thickness Tc of the AM component 12X comprised by the pad 36X at that given one of the front portion 23 and the back portion 31 of the helmet 10 may be no more than 22 mm, in some cases no more than 20 mm, in some cases no more than 18 mm, and in some cases no more than 16 mm (e.g., 15 mm or less). In some cases, the thickness Tc of the AM component 12X comprised by the pad 36X at that given one of the front portion 23 and the back portion 31 of the helmet 10 may be thicker than the thickness Tc of the AM component 12X or another one of the AM components 121-12A at a given one of the lateral side portions 44L, 44R of the helmet 10.
[0150]For instance, in some embodiments, the AM component 12X comprised by the pad 36X may be configured such that, when the helmet 10 is impacted where the AM component 12X is located in accordance with hockey STAR methodology, linear acceleration at a center of gravity of a headform on which the helmet 10 is worn is no more than a value indicated by curves L1-L3 shown in FIGS. 21A-21C for impacts at three energy levels (10 Joules, 40 Joules and 60 Joules, respectively) according to hockey STAR methodology for the thickness Tc of the AM component 12X where impacted.
[0151]In some embodiments, the AM component 12X comprised by the pad 36X may be configured such that, when the helmet 10 is impacted where the AM component 12X is located in accordance with hockey STAR methodology, the linear acceleration at the center of gravity of the headform on which the helmet 10 is worn may be no more than 120%, in some cases no more than 110%, and in some cases no more than 105% of the value indicated by the curves L1-L3 for impacts at three energy levels according to hockey STAR methodology for the thickness Tc of the AM component 12X where impacted. For example, the values indicated by the upper bound curves L1upper-L3upper shown in FIGS. 21A-21C are 20% higher than those of the curves L1-L3.
[0152]In some embodiments, the AM component 12X comprised by the pad 36X may be configured such that, when the helmet 10 is impacted where the AM component 12X is located in accordance with hockey STAR methodology, the linear acceleration at the center of gravity of the headform on which the helmet 10 is worn may be no more than 90%, in some cases no more than 80%, and in some cases no more than 70% of the value indicated by the curves L1-L3 for impacts at three energy levels according to hockey STAR methodology for the thickness Tc of the AM component 12X where impacted. For example, the values indicated by the lower bound curves L1lower-L3lower shown in FIGS. 21A-21C are 30% lower than those of the curves L1-L3.
[0153]The hockey STAR methodology is a testing protocol described in a paper entitled “Hockey STAR: A Methodology for Assessing the Biomechanical Performance of Hockey Helmets”, by B. Rowson et al., Department of Biomedical Engineering and Mechanics, Virginia Tech, 313 Kelly Hall, 325 Stanger Street, Blacksburg, Va. 24061, USA, published online on Mar. 30, 2015 and incorporated by reference herein.
[0154]The AM component 12X comprised by the pad 36X may be designed to have properties of interest in this regard.
[0155]For example, in some embodiments, the AM component 12X comprised by the pad 36X may be configured in order to provide a desired stiffness. The stiffness of the AM component 12X may be measured by applying a compressive load to the AM component 12X, measuring a deflection of the AM component 12X where the compressive load is applied, and dividing the compressive load by the deflection.
[0156]As another example, in some embodiments, the AM component 12X comprised by the pad 36X may be configured in order to provide a desired resilience according to ASTM D2632-01 which measures resilience by vertical rebound.
[0157]As another example, in some embodiments, the AM component 12X comprised by the pad 36X may be configured such that, when the AM component 12X is loaded and unloaded, e.g., as a result of a stress temporarily applied to the pad 36X from an impact on the helmet 10, the strain of the AM component 12X is no more than a value indicated by the unloading curve shown in FIG. 22A for the unloading of the applied stress. In addition, or instead, in some embodiments, the AM component 12X comprised by the pad 36X may be configured such that when the AM component 12X is loaded and unloaded the stress required to realize a given strain on the loading curve may be higher or lower than that of the loading curve shown in FIG. 22A, but the difference in stress between the loading and unloading curves at a given level of strain is at least as large as the difference between the loading and unloading curves shown in FIG. 22A at the given level of strain. In general, the greater the area between the loading and unloading curves for an impact absorbing component, the greater the impact energy that is absorbed by that component. For example, an impact absorbing component having the same loading curve as shown in FIG. 22B, but a lower unloading curve, as illustrated by a second dashed unloading curve in FIG. 22B, would dissipate a greater amount of impact energy.
[0158]In this embodiment, the AM component 12X comprised by the pad 36X includes a lattice 140, an example of which is shown in FIG. 23, which is additively-manufactured such that AM component 12X has an open structure. The lattice 140 can be designed and 3D-printed to impart properties and functions of the AM component 12X, such as those discussed above, while helping to minimize its weight.
[0159]The lattice 140 comprises a framework of structural members 1411-141E (best shown in FIG. 24A) that intersect one another. In some embodiments, the structural members 1411-141E may be arranged in a regular arrangement repeating over the lattice 140. In some cases, the lattice 140 may be viewed as made up of unit cells 1321-132C each including a subset of the structural members 1411-141E that forms the regular arrangement repeating over the lattice 140. Each of these unit cells 1321-132C can be viewed as having a voxel (shown in dashed lines in FIGS. 23 and 24A), which refers to a notional three-dimensional space that it occupies. In other embodiments, the structural members 1411-141E may be arranged in different arrangements over the lattice 140 (e.g., which do not necessarily repeat over the lattice 140, do not necessarily define unit cells, etc.).
[0160]The lattice 140, including its structural members 1411-141E, may be configured in any suitable way.
[0161]In this embodiment, the structural members 1411-141E are elongate members that intersect one another at nodes 1421-142N. The elongate members 1411-141E may sometimes be referred to as “beams” or “struts”. Each of the elongate members 1411-141E may be straight, curved, or partly straight and partly curved.
[0162]The 3D-printed material 50 constitutes the lattice 140. Specifically, the elongate members 1411-141E and the nodes 1421-142N of the lattice 140 include respective parts of the 3D-printed material created by the 3D-printer.
[0163]In this example of implementation, the 3D-printed material 50 includes polymeric material. For instance, in this embodiment, the 3D-printed material 50 may include polyamide (PA) 11, thermoplastic polyurethane (TPU) 30A to 95A (fused), polyurethane (PU) 30A to 95A (light cured, chemical cured), polyether ether ketone (PEEK), polyetherketoneketone (PEKK), polypropylene (PP), silicone, rubber, gel and/or any other polymer.
[0164]In some embodiments, the AM components 121-12A may comprise a plurality of materials different from one another. For example, a first one of the materials is a first polymeric material and a second one of the materials is a second polymeric material. In other embodiments, a first one of the materials may be a polymeric material and a second one of the materials may be a non-polymeric material.
[0165]In some embodiments, the structural members 1411-141E of the lattice 140 may be implemented in various other ways. For example, in some embodiments, the structural members 1411-141E may be planar members that intersect one another at vertices. For example, such an embodiment of the lattice 140 may be realized using a different “mesh” or “shell” style unit cell, such as the unit cell 1321 shown in FIG. 24B, which includes planar members 1411-141E that intersect at vertices 1421-142V. The surfaces of the planar members 1411-141E may sometimes be referred to as “faces”. Each of the planar members 1411-141E may be straight, curved, or partly straight and partly curved. In some embodiments, the structural members 1411-141E of the lattice 140 may have a hybrid construction that includes both elongate members and planar members. For example, such embodiments may include a mix of elongate member style unit cells, such as the unit cell 1321 shown in FIG. 24A, and mesh or shell style unit cells, such as the unit cell 1321 shown in FIG. 24B. In some embodiments, the structural elements of a unit cell may include a combination of elongate member and surface/planar members. FIGS. 24C, 24D and 24E show further non-limiting examples of elongate member style unit cells and mesh or shell style unit cells that may be used individually and/or in combination to form additively-manufactured components as disclosed herein. The example unit cells shown in FIG. 24E are examples of cubic unit cells that are based on triply periodic minimal surfaces. A minimal surface is the surface of minimal area between any given boundaries. Minimal surfaces have a constant mean curvature of zero, which means that the sum of the principal curvatures at each point is zero. Triply periodic minimal surfaces have a crystalline structure, in that they repeat themselves in three dimensions, and thus are said to be triply periodic.
[0166]A volume of material can be constructed by “voxelizing” the volume (dividing the volume into voxels of the same or different sizes), and populating the voxels with unit cell structures, such as those shown in FIGS. 24A-24E. For example, FIG. 24F shows three examples of volumes containing triply periodic surfaces implemented by 2×2×2 lattices of equal sized voxels populated with different unit cells from the examples shown in FIG. 24D. The behavior or performance of an AM component that includes a voxelized volume of unit cells can be adapted by changing the structure, size or combination of unit cells that make up the AM component. Unit cells having different structures (e.g., the body centered (BC) unit cell shown in FIG. 24A vs. the Schwarz P unit cell shown in FIG. 24E) may have different behaviors. Similarly, unit cells having the same structure but different sizes may behave differently. Furthermore, implementing unit cells using the same structure but using different materials may result in different behaviors. Likewise, implementing an AM component using multiple different types of unit cells that differ in terms of structure, size and/or materials may result in different behavior/performance. As such, it may be possible to achieve a desired performance of an AM component by adapting the structure, size, material and/or mix of the unit cells that are used within a given volume of the AM component. This concept is discussed in further detail below with reference to FIGS. 25A-25G.
[0167]FIG. 25A shows four different cubic unit cells 300, 302, 304 and 306. Unit cells 300, 304 and 306 are of the same size, but exhibit different behaviors which are identified generically as Behavior A, Behavior B and Behavior C, respectively. For example, unit cells 300, 302 and 306 may differ in terms of structure and/or materials, and thereby provide different impact absorbency properties, such as resiliency, stiffness, modulus of elasticity, etc.
[0168]Unit cells 300 and 302 are characterized by the same behavior, Behavior A, but unit cell 302 is smaller than the other three unit cells 300, 304 and 306. In particular, in this example unit cell 302 is one eighth the volume of the other three unit cells 300, 304 and 306, such that a 2×2×2 lattice of unit cells 302 would have the same volume of each of the other three unit cells 300, 304 and 306. This is shown by way of example in FIG. 25B, which shows that an AM component occupying a volume 310 may be implemented by either a 3×3×2 lattice of unit cells 300 or a 6×6×4 lattice of unit cells 302.
[0169]As noted above, the behavior of an AM component constituting a voxelized volume of unit cells may be changed by incorporating different unit cells within the volume. This is shown by way of example in FIGS. 25C-25G. FIG. 25C shows that a smaller volume 310 within a larger volume 320 of an AM component may be implemented with a 3×3×2 lattice of unit cells 300 characterized by Behavior A, while the remainder of volume 320 is implemented with unit cells 304 characterized by Behavior B. Such a combination of unit cells 300 and 304 may result in an overall behavior for the AM component that is different than either Behavior A or Behavior B alone. FIG. 25D shows an alternative example in which the smaller volume 310 is implemented with a 6×6×4 lattice of unit cells 302. FIG. 25E shows another example of this concept, in which the voxelized volume 320 of unit cells shown in FIG. 25C, which includes a mix of unit cells 300 and 304, is located within an even larger voxelized volume 330 of an AM component. In this example, the remainder of the volume 330 of the AM component is implemented with unit cells 306 characterized by Behavior C. FIG. 25F shows a profile of the cross-section of the AM component of FIG. 25E along the line A-A. FIG. 25G shows a profile of the cross-section of an alternative example in which the smaller volume 310 within the volume 320 is implemented with a 6×6×4 lattice of unit cells 302 rather than a 3×3×2 lattice of unit cells 300.
[0170]Referring again to FIGS. 16 to 20, in some embodiments, an AM component 12X may include a non-lattice member connected to the lattice 140. For example, the non-lattice member may be configured to be positioned between the lattice 140 and a user's head when the helmet is worn. In other embodiments, the non-lattice member may be positioned between the lattice 140 and the shell 11. In some embodiments, such a non-lattice member may be thinner than the lattice 140. In other embodiments, the non-lattice member may be bulkier than the lattice 140.
[0171]In the example of implementation shown in FIG. 23, the lattice 140 of the AM component 12X comprised by the pad 36X may include outer surfaces or “skins” that provide interfaces to other components of the helmet and/or the user's head. The outer surfaces of the l