Embodiments described herein relate generally to apparatus with ribbed structures or geometries for stiffness and damping control, and methods of producing the same. In some embodiments, an apparatus includes a ribbed structure having a set of ribs, configured to deform elastically under shock. In some embodiments, the set of ribs can have a sinusoidal wave shape. In some embodiments, the set of ribs can have a heterogeneous wave shape. In some embodiments, the set of ribs can have material properties that change along the length of the ribbed structure, such as wavelength, amplitude, wave shape, and material thickness.

Stability of shock absorbing property of a shock absorber provided on a back surface of a door trim is improved. A shock absorber is attached on the back surface of the door trim, and absorbs impact applied to the door. A quadrangular tube element of the shock absorber has an end plate on a tube tip surface, and faces the back surface of the door trim. The quadrangular tube element has an approximate U shape in which three side surfaces are closed by an upper plate, a lower plate, and a front plate, and the remaining one side surface is opened.

A damper member may include a gel-like member and a first film joined to a first surface of the gel-like member in a thickness direction, in which a side surface of the gel-like member located between a second surface opposite to the first surface of the gel-like member in the thickness direction and the first surface is opened.

A body limb protection system includes an outer layer, an inner layer, and a force dampening and defusing structure. The outer layer includes a first material composition and has an exterior surface that includes a substantially planer area. The inner layer includes a second material composition and has a shape corresponding to a body limb portion. The force dampening and defusing structure is positioned between the inner layer and the outer layer. The force dampening and defusing structure has a shape corresponding to a difference between the shapes of the inner and outer layers. The force dampening and defusing structure includes a plurality of components arranged to reduce pressure on the body limb portion when a force is applied to the substantially planer area.

A structural member 10 includes a hat member 1 and a closing plate 2. The length LY of the tubular portion formed by the hat member 1 and the closing plate 2 is 6 or more times the height H of a pair of side walls 11 and 12. Each of the side walls 11 and 12 includes a high-strength portion 11A or 12A and low-strength portions 11B or 12B. The high-strength portion has a yield strength not less than 500 MPa. The low-strength portions have a yield strength of 60 to 85% of that of the high-strength portion. Each high-strength portion extends a distance not less than (⅔)H and not more than 3H as measured in the direction in which the ridges extend, and is provided such that the high-strength portions of the pair of side walls face each other. A pair of low-strength portions sandwich the associated high-strength portion.

The present disclosure provides a rotational spring dampener that has a compression limiter, a first disk, and a second disk. The first disk is disposed at a first end of the compression limiter and the second disk is disposed at a second end of the compression limiter, where the second end is opposite the first end. The rotational spring dampener also has a tensile member. The tensile member is connected to the first disk and the second disk. The tensile member is composed of a block copolymer

An impact absorbing member 10 able to secure absorption energy while lightening weight by absorbing the impact load applied in the axial direction by periodic buckling, wherein the impact absorbing member 10 is provided with a main body 20 comprised of metal sheet and having a polygonal shape in cross-section vertical to an axial direction and a center sheet 30 comprised of metal sheet and provided at a hollow part in the main body along the axial direction, the polygonal shape of the main body 20 includes a pair of long side (20a, 20b) facing each other, the center sheet 30 is joined to each of the long sides (20a, 20b) of the polygonal shape of the main body 20, and the sheet thickness t1 (mm) of the main body 20 and the sheet thickness t2 (mm) of the center sheet 30 satisfy 1.3×t1≦t2.

A landing gear includes a pair of skids, a cross tube and a stiffening portion. The pair of skids is arranged in parallel with a front-rear axis of an airframe of a rotary wing aircraft. The cross tube is attached to the airframe and coupling the pair of skids to each other. The cross tube includes curved portions located closer to end portions of the cross tube than to portions of the cross tube attached to the airframe. The stiffening portion suppresses flattening of the cross tube and is arranged in at least one of internal spaces of the curved portions or a stiffened portion located between a pair of curved portions. The stiffening portion includes an enlarged diameter portion which increases in diameter by an axial fastening power acting in an axial direction of the cross tube, and a fastening portion configured to generate the axial fastening power.

A body impact protection system includes an inner layer and an impact force dampening and defusing structure. The inner layer includes a material composition and is adjacent to a body part when the body impact protection system is worn. The impact force dampening and defusing structure is juxtaposed to the inner layer and includes a plurality of components. The components function to reduce pressure on the body part from an impact force on a layer by layer basis. Each layer of the system dampens and defuses the impact force such that, by the time it reaches the body part, it has been substantially attenuated and spread over a large area.

A body impact protection system includes an inner layer and an impact force dampening and defusing structure. The inner layer includes a material composition and is adjacent to a body part when the body impact protection system is worn. The impact force dampening and defusing structure is juxtaposed to the inner layer and includes a plurality of components. The components function to reduce pressure on the body part from an impact force on a layer by layer basis. Each layer of the system dampens and defuses the impact force such that, by the time it reaches the body part, it has been substantially attenuated and spread over a large area.