Origami Pattern
The art of paper folding is often associated with Japanese culture. The goal of paper folding has always been to convert 2D sheets into our desired 3D stable configurations. These structures can be simply classified as Rigid Origami and Non-Rigid Origami.
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Rigid Origami
“Which origami models can be opened (to a completely flat, unfolded state) and closed (to the completely folded state) in a rigid manner?” By rigid, it means that the regions of paper between crease lines do not need to bend or twist in the folding process. Considering a simple example, if we replace a paper with sheet metal and place hinges at the crease lines, we would still be able to fold the model, famed for his Miura Map fold, which is a rigid fold that has been used to deploy massive solar panel arrays for space spacecraft Miura (1989), created one of the most famous stiff origami examples.
The crease patterns for Miura Ori form a tessellation of the parallelograms where each adjected parallelogram forms the reflection of its neighbour sharing the same crease. The pattern has the ability to deform completely in one direction without causing any deformation on facets.
Non-Rigid Origami
Non-rigid Origami or Dynamic Origami has the ability to deform. An example for such origami which plays a huge aspect to this project is the ‘Waterbomb’ structure or the ‘Magic Air Ball’ pattern. The pattern has the capability to deform into sphere or cylinder when force is applied axially or radially.
Another famous pattern proposed by Kresling John and COOKE (2008),was the “Kresling Pattern” to investigate change in folding pattern when a cylindrical tube is subjected to torsional load. Zhang et al. (2018) aims to analyse the bistable behaviour for the deployment of kresling pattern along with a numerical study to validate the theoretical solutions.
Kresling pattern, from a geometrical perspective is considered to be not rigidly foldable and cannot deform from the nominal, expanded state purely by folding at the creases. However, folding constructions based on origami have two drawbacks. For starters, its foldability is restricted from the folded to the planar state. Although multiple folding patterns can be used to adjust it, the planar state still prescribes the same constraint. Second, the folded condition contains uneven surfaces, which causes problems when integrating with planar systems, however this issue can be mitigated to some extent
Waterbomb Pattern
Commonly, two terms are related to it: Waterbomb bases and Waterbomb tessellations. There are two types of Waterbomb bases: the eight-crease base and the six-crease base. The former is made from a square sheet of paper consisting of eight alternating mountain and valley creases around a central vertex. One of its typical tessellations is produced by four such bases tiling around a smaller square forming the square Resch pattern. The latter, consisting of two mountain and four valley creases, is more commonly known, and its tessellations range from a flat-foldable surface to a deformable tube known as the magic origami ball Owing to its large deployable ratio between expanded and packaged states, it can be potentially used to fold large flat roofs and space solar panels.
To change the degrees of freedom of the wheel’s construction, we have used 2 types of facets: stiff and flexible. Following the conventional origami design procedure we have used the same stiffness for our facets and crease lines. Despite the fact that the proposed design loses a significant advantage of tremendous adaptability given by soft materials, it offers us three key advantages.
- The structure can be constructed without the need of numerous mechanical pieces or a time-consuming process. Most parts are replaced by a single sheet, and each joint is generated by a folding part which not only minimizes the cost of manufacture but also the time necessary for assembly.
- In comparison to its weight, an origami structure might have a high rigidity and impact capacity.
- An origami structure is scalable
An origami structure is composed of compliant folding parts and facets, so the whole structure can perform as a shock absorber. This study describes a new version of the wheel transformation along with a comprehensive analysis of the structure. The kinematic model of the wheel structure allows the analysis and optimisation of the design parameters. The whole wheel transformation mechanism design incorporates special components such as set of wheel hubs, shaft support and mechanism housing aiming to improve the overall performance.