A crash box may include one or more layers arranged to absorb crash energy. In some embodiments, the crash box includes a first layer having an outer skin defining a periphery of the first layer and at least one of: 1) a rib and web structure, and 2) an array of tubes disposed within the outer skin for absorbing crash energy, and a second layer adjacent to the first layer, the second layer having an outer skin defining a periphery of the second layer and at least one of: 1) a rib and web structure, and 2) an array of tubes disposed within the outer skin for absorbing crash energy.

A rail extension system (16), comprising: a vehicle rail (60); a bumper beam (20); a polymeric rail extension (1) comprising: a base (2) extending from one end of the rail extension having vehicle attachment configured to attach to the vehicle rail (60); a front member 4) configured for attachment to the bumper beam (20); a body (5) extending from the base (2) to the front member (4); an aperture (100) extending from the base (2) to the front member (4); a connection member (102) attached to the bumper beam (20) and extending through the aperture (100) to attach to the vehicle rail (60).

This shock-absorbing member comprises a molded part containing a thermoplastic resin. The molded part is provided with a main body having a honeycomb structure filled with a plurality of tubular cells. All or some of the tubular cells constituting the honeycomb structure are arrayed with cell walls interposed therebetween, the cell walls having a thickness gradient that satisfies the relationship of expression (G) and that is found by the following method of calculating the cell wall thickness gradient.

[Method of calculating the cell wall thickness gradient]

Procedure 1): set a central axis (a), which passes through one end-surface center of gravity and another end-surface center of gravity in a first tubular cell that has a height (H).

Procedure 2): set any two faces (b) and (c) perpendicular to the central axis (a) within the range of the height (H) of the first tubular cell, and let the distance between the two faces (b) and (c) be h (units: mm; 0<h<H).

Procedure 3): let the thickness of the cell wall between the first tubular cell and a second tubular cell adjacent thereto be (t1) (units: mm) at a location where the cell wall and the surface (b) cross.

Procedure 4): let the thickness of the cell wall between the first tubular cell and the second tubular cell adjacent thereto be (t2) (units: mm) at a location where the cell wall and the surface (c) cross.

Procedure 5): calculate (|t2?t1|/h) as the cell wall thickness gradient.

[00001]$\begin{array}{cc}\left[\mathrm{Math}.1\right]& ?\\ 62.5?{10}^{-4}<\frac{.Math.t2-t1.Math.}{h}<250?{10}^{-4}& \left(G\right)\end{array}$

An impact energy absorbing device for a vehicle includes a plurality of cells that are grouped together to form a matrix structure defining a mounting region and a contact region. The cells crush along their respective longitudinal axes when exposed to an impact force on the contact region. Each of the longitudinal axes of the plurality of cells in the matrix structure diverges with respect to neighboring cells in a direction from the mounting region to the contact region.

In one example, a load-bearing, three-dimensional printed part resists a load. The load-bearing part has a load-receiving member, a support member, and a network of interconnected branches. The load-receiving member has an outer surface that receives the load. The support member is offset from the load-receiving member along a first direction. The network of interconnected branches extends from the load-receiving member to the support member, and includes a first primary branch and an auxiliary branch. The first primary branch has a first primary-branch end attached to one of the load-receiving member and the support member. The auxiliary branch has a first auxiliary-branch end attached to the first primary branch, and a second auxiliary-branch end attacked to one of (i) the load-receiving member, (ii) the support member, and (iii) a second primary branch.

A crush-can is provided. That crush-can includes a first wall, a second wall within the first wall and a corrugated core between the first wall and the second wall. A method for producing the crush-can via 3D printing is also disclosed.

A bumper for a vehicle includes a crossbeam, a first crush can, and a second crush can. The first crush can extends vehicle-rearward from the crossbeam to the first frame rail along the vehicle-longitudinal axis and the second crush can extend vehicle-rearward from the crossbeam to the second frame rail along the vehicle-longitudinal axis. The bumper has a topmost surface along the crossbeam, the first crush can, and the second crush can. The bumper has a bottommost surface along the crossbeam, the first crush can, and the second crush can. The crossbeam, the first crush can, and the second crush can have a lattice shape defining cells. At least some of the cells are elongated through both the topmost surface and the bottommost surface. The crossbeam, the first crush can, and the second crush can are unitary with each other.