Rotational expansion auxetic structures
OwnerWilliam Jacob Spenner Dollainventor
Life of this patent
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Abstract
Auxetic structures exhibiting negative Poisson's ratios are disclosed including planar auxetic structures formed from x-axis and y-axis strands of selected waveforms. Portions of the auxetic structure referred to as unit cells comprise four joints formed by two adjacent x-axis strands overlapping two adjacent y-axis strands display symmetry about x and y axes. Each unit cell comprises four sub-unit cells formed from segments of ½ wavelength of the wave form. The planar auxetic structures may be formed into three-dimensional auxetic structures or cylindrical or spherical auxetic structures.
Claims25
An auxetic structure formed from a plurality of x-axis strands and y-axis strands wherein each of said x-axis strands comprises a wave pattern oscillating about an axis extending in parallel relation to an x-axis and each of said y-axis strands comprises a wave pattern oscillating abut an axis extending in parallel relation to a y-axis;
- the wave pattern of each x-axis strand is offset from the wave pattern of each adjacent x-axis strand by 180 degrees and the wave pattern of each y-axis strand is offset from the wave pattern of each adjacent y-axis strand by 180 degrees;
- said x-axis strands and said y-axis strands being joined together at nodes where said x-axis strands and said y-axis strands intersect, and wherein an x-axis sub-unit cell segment comprising a portion of said x-axis strand of ½ a wavelength and a y-axis sub-unit cell segment comprising a portion of said y-axis strand of ½ a wavelength extend through each joint to form a sub-unit cell and wherein each sub unit cell is a mirror image of each adjacent sub-unit cell both across axis extending parallel to the x-axis and across axis extending parallel to the y-axis;
- wherein at least one x-axis flex point is formed on each of said x-axis strands between adjacent x-axis sub-unit cell segments and said x-axis flex points are more flexible than said nodes;
- and wherein at least one y-axis flex point is formed on each of said x-axis strands between adjacent y-axis sub unit cell segments and said y-axis flex points are more flexible than said nodes.
An auxetic structure formed from a plurality of x-axis strands and y-axis strands wherein each of said x-axis strands comprises a wave pattern oscillating about an axis extending in parallel relation to an x-axis and each of said y-axis strands comprises a wave pattern oscillating abut an axis extending in parallel relation to a y-axis;
- the wave pattern of each x-axis strand is offset from the wave pattern of each adjacent x-axis strand by 180 degrees and the wave pattern of each y-axis strand is offset from the wave pattern of each adjacent y-axis strand by 180 degrees;
- said x-axis strands and said y-axis strands being joined together at joints where said x-axis strands and said y-axis strands intersect, and wherein an x-axis sub-unit cell segment comprising a portion of said x-axis strand of ½ a wavelength and a y-axis sub-unit cell segment comprising a portion of said y-axis strand of ½ a wavelength extend through each joint to form a sub-unit cell and wherein each sub unit cell is a mirror image of each adjacent sub-unit cell both across axis extending parallel to the x-axis and across axis extending parallel to the y-axis;
- wherein each x-axis sub-unit cell segment is separated from an adjacent x-axis sub-unit cell segment by a sinusoidal connector and each y-axis sub-unit cell segment is separated from an adjacent y-axis sub-unit cell segment by a sinusoidal connector.
A three dimensional auxetic structure comprising:
- a plurality of auxetic structures formed from a plurality of x-axis strands and y-axis strands wherein each of said x-axis strands comprises a wave pattern oscillating about an axis extending in parallel relation to an x-axis and each of said y-axis strands comprises a wave pattern oscillating abut an axis extending in parallel relation to a y-axis;
- the wave pattern of each x-axis strand is offset from the wave pattern of each adjacent x-axis strand by 180 degrees and the wave pattern of each y-axis strand is offset from the wave pattern of each adjacent y-axis strand by 180 degrees;
- said x-axis strands and said y-axis strands being joined together at joints where said x-axis strands and said y-axis strands intersect, and wherein an x-axis sub-unit cell segment comprising a portion of said x-axis strand of ½ a wavelength and a y-axis sub-unit cell segment comprising a portion of said y-axis strand of ½ a wavelength extend through each joint to form a sub-unit cell and wherein each sub unit cell is a mirror image of each adjacent sub-unit cell both across axis extending parallel to the x-axis and across axis extending parallel to the y-axis;
- wherein
- a plurality of said auxetic structures extend in parallel xy axis planes;
- a plurality of said auxetic structures extend in parallel yz axis planes;
- and
- a plurality of said auxetic structures extend in parallel zx axis planes;
- and
- wherein intersections between each xy axis auxetic structure with a yz axis auxetic structure and a zx axis auxetic structure are formed at joints of said respective auxetic structures.
An auxetic structure formed from a plurality of x-axis strands and y-axis strands wherein each of said x-axis strands comprises a sinusoidal wave pattern oscillating about an axis extending in parallel relation to an x-axis and each of said y-axis strands comprises a sinusoidal wave pattern oscillating abut an axis extending in parallel relation to a y-axis;
- the sinusoidal wave pattern of each x-axis strand is offset from the sinusoidal wave pattern of each adjacent x-axis strand such that the peaks and valleys of one x-axis strand are aligned with the valleys and peaks respectively of each adjacent x-axis strand and the sinusoidal wave pattern of each y-axis strand is offset from the sinusoidal wave pattern of each adjacent y-axis strand such that the peaks and valleys of one y-axis strand are aligned with the valleys and peaks respectively of each adjacent y-axis strand;
- said x-axis strands and said y-axis strands being joined together at nodes where said x-axis strands and said y-axis strands intersect, and wherein an x-axis sub-unit cell segment comprising a portion of said x-axis strand of ½ a wavelength and a y-axis sub-unit cell segment comprising a portion of said y-axis strand of ½ a wavelength extend through each joint to form a sub-unit cell and wherein each sub unit cell is a mirror image of each adjacent sub-unit cell both across axis extending parallel to the x-axis and across axis extending parallel to the y-axis;
- wherein at least one x-axis flex point is formed on each of said x-axis strands between adjacent x-axis sub-unit cell segments and said x-axis flex points are more flexible than said nodes;
- and wherein at least one y-axis flex point is formed on each of said x-axis strands between adjacent y-axis sub unit cell segments and said y-axis flex points are more flexible than said nodes.
A three dimensional auxetic structure comprising;
- a plurality of auxetic structures formed from a plurality of x-axis strands and y-axis strands wherein each of said x-axis strands comprises a sinusoidal wave pattern oscillating about an axis extending in parallel relation to an x-axis and each of said y-axis strands comprises a sinusoidal wave pattern oscillating abut an axis extending in parallel relation to a y-axis;
- the sinusoidal wave pattern of each x-axis strand is offset from the sinusoidal wave pattern of each adjacent x-axis strand such that the peaks and valleys of one x-axis strand are aligned with the valleys and peaks respectively of each adjacent x-axis strand and the sinusoidal wave pattern of each y-axis strand is offset from the sinusoidal wave pattern of each adjacent y-axis strand such that the peaks and valleys of one y-axis strand are aligned with the valleys and peaks respectively of each adjacent y-axis strand;
- said x-axis strands and said y-axis strands being joined together at joints where said x-axis strands and said y-axis strands intersect, and wherein an x-axis sub-unit cell segment comprising a portion of said x-axis strand of ½ a wavelength and a y-axis sub-unit cell segment comprising a portion of said y-axis strand of ½ a wavelength extend through each joint to form a sub-unit cell and wherein each sub unit cell is a mirror image of each adjacent sub-unit cell both across axis extending parallel to the x-axis and across axis extending parallel to the y-axis;
- wherein
- a plurality of said auxetic structures extend in parallel xy axis planes;
- a plurality of said auxetic structures extend in parallel yz axis planes;
- and
- a plurality of said auxetic structures extend in parallel zx axis planes;
- and
- wherein intersections between each xy axis auxetic structure with a yz axis auxetic structure and a zx axis auxetic structure are formed at joints of said respective auxetic structures.
A planar auxetic structure formed from a plurality of x-axis strands and y-axis strands wherein each of said x-axis strands comprises a wave pattern oscillating about an axis extending in parallel relation to an x-axis and each of said y-axis strands comprises a wave pattern oscillating abut an axis extending in parallel relation to a y-axis;
- the wave pattern of each x-axis strand is offset from the wave pattern of each adjacent x-axis strand by 180 degrees and the wave pattern of each y-axis strand is offset from the wave pattern of each adjacent y-axis strand by 180 degrees;
- said x-axis strands and said y-axis strands being joined together at joints where said x-axis strands and said y-axis strands intersect, and wherein an x-axis sub-unit cell segment comprising a portion of said x-axis strand of ½ a wavelength and a y-axis sub-unit cell segment comprising a portion of said y-axis strand of ½ a wavelength extend through each joint to form a sub-unit cell and wherein each sub unit cell is a mirror image of each adjacent sub-unit cell both across axis extending parallel to the x-axis and across axis extending parallel to the y-axis;
- wherein a cross-link extends between ends of x-axis sub-unit cell segments of adjacent x-axis strands that are spaced apart at a maximum spacing and a cross-link extends between ends of y-axis sub-unit cell segments of adjacent y-axis strands that are spaced apart at a maximum spacing.
Dependencies are inferred from the claim text.