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Sequential Self-Folding Structures by 3D Printed Digital Shape Memory Polymers.

Mao Y, Yu K, Isakov MS, Wu J, Dunn ML, Jerry Qi H - Sci Rep (2015)

Bottom Line: A simplified reduced-order model is also developed to rapidly and accurately describe the self-folding physics.An important aspect of self-folding is the management of self-collisions, where different portions of the folding structure contact and then block further folding.A metric is developed to predict collisions and is used together with the reduced-order model to design self-folding structures that lock themselves into stable desired configurations.

View Article: PubMed Central - PubMed

Affiliation: The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.

ABSTRACT
Folding is ubiquitous in nature with examples ranging from the formation of cellular components to winged insects. It finds technological applications including packaging of solar cells and space structures, deployable biomedical devices, and self-assembling robots and airbags. Here we demonstrate sequential self-folding structures realized by thermal activation of spatially-variable patterns that are 3D printed with digital shape memory polymers, which are digital materials with different shape memory behaviors. The time-dependent behavior of each polymer allows the temporal sequencing of activation when the structure is subjected to a uniform temperature. This is demonstrated via a series of 3D printed structures that respond rapidly to a thermal stimulus, and self-fold to specified shapes in controlled shape changing sequences. Measurements of the spatial and temporal nature of self-folding structures are in good agreement with the companion finite element simulations. A simplified reduced-order model is also developed to rapidly and accurately describe the self-folding physics. An important aspect of self-folding is the management of self-collisions, where different portions of the folding structure contact and then block further folding. A metric is developed to predict collisions and is used together with the reduced-order model to design self-folding structures that lock themselves into stable desired configurations.

No MeSH data available.


The self sequential self-folding (a) without collisions; (b) with collisions.When there is no collision, all collision indices are out of span (0, 1) (shown in (a)), and when there is a collision, the index falls in span (0, 1) (as shown in (b), two points (a red and a blue point) are in span (0, 1)). The red dot between (0, 1) corresponds to first collision; the blue dot corresponds to the second collision.
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f4: The self sequential self-folding (a) without collisions; (b) with collisions.When there is no collision, all collision indices are out of span (0, 1) (shown in (a)), and when there is a collision, the index falls in span (0, 1) (as shown in (b), two points (a red and a blue point) are in span (0, 1)). The red dot between (0, 1) corresponds to first collision; the blue dot corresponds to the second collision.

Mentions: Utilizing the ROM simulation, we develop a simple collision index, which can be used to determine if two panels will collide during the folding process. As described in the Methods section, the collision index, Sij, is calculated based on the motion of any pair of panels (the i-th panel and the j-th panel) during each time increment of the simulation. In general, when 0 < Sij < 1, a collision will occur. Figure 4a,b show the collision indices of the two designs discussed above; there are 10 panels in each design which gives rise to 45 unique panel pairs. In Fig. 4a, the structure can fold without collisions, therefore, no collision index falls between the band between 0 and 1 during the simulation. In Fig. 3c two collisions occurred between panels and the structure cannot fold to its target shape; Fig. 4b reflects this as two collision indices fall in span(0, 1). In the figure, the red dot between (0, 1) corresponds to first collision; the blue dot corresponds to the second collision. More collision will happen; but since our interest is the first collision, no further calculation is conducted.


Sequential Self-Folding Structures by 3D Printed Digital Shape Memory Polymers.

Mao Y, Yu K, Isakov MS, Wu J, Dunn ML, Jerry Qi H - Sci Rep (2015)

The self sequential self-folding (a) without collisions; (b) with collisions.When there is no collision, all collision indices are out of span (0, 1) (shown in (a)), and when there is a collision, the index falls in span (0, 1) (as shown in (b), two points (a red and a blue point) are in span (0, 1)). The red dot between (0, 1) corresponds to first collision; the blue dot corresponds to the second collision.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562068&req=5

f4: The self sequential self-folding (a) without collisions; (b) with collisions.When there is no collision, all collision indices are out of span (0, 1) (shown in (a)), and when there is a collision, the index falls in span (0, 1) (as shown in (b), two points (a red and a blue point) are in span (0, 1)). The red dot between (0, 1) corresponds to first collision; the blue dot corresponds to the second collision.
Mentions: Utilizing the ROM simulation, we develop a simple collision index, which can be used to determine if two panels will collide during the folding process. As described in the Methods section, the collision index, Sij, is calculated based on the motion of any pair of panels (the i-th panel and the j-th panel) during each time increment of the simulation. In general, when 0 < Sij < 1, a collision will occur. Figure 4a,b show the collision indices of the two designs discussed above; there are 10 panels in each design which gives rise to 45 unique panel pairs. In Fig. 4a, the structure can fold without collisions, therefore, no collision index falls between the band between 0 and 1 during the simulation. In Fig. 3c two collisions occurred between panels and the structure cannot fold to its target shape; Fig. 4b reflects this as two collision indices fall in span(0, 1). In the figure, the red dot between (0, 1) corresponds to first collision; the blue dot corresponds to the second collision. More collision will happen; but since our interest is the first collision, no further calculation is conducted.

Bottom Line: A simplified reduced-order model is also developed to rapidly and accurately describe the self-folding physics.An important aspect of self-folding is the management of self-collisions, where different portions of the folding structure contact and then block further folding.A metric is developed to predict collisions and is used together with the reduced-order model to design self-folding structures that lock themselves into stable desired configurations.

View Article: PubMed Central - PubMed

Affiliation: The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.

ABSTRACT
Folding is ubiquitous in nature with examples ranging from the formation of cellular components to winged insects. It finds technological applications including packaging of solar cells and space structures, deployable biomedical devices, and self-assembling robots and airbags. Here we demonstrate sequential self-folding structures realized by thermal activation of spatially-variable patterns that are 3D printed with digital shape memory polymers, which are digital materials with different shape memory behaviors. The time-dependent behavior of each polymer allows the temporal sequencing of activation when the structure is subjected to a uniform temperature. This is demonstrated via a series of 3D printed structures that respond rapidly to a thermal stimulus, and self-fold to specified shapes in controlled shape changing sequences. Measurements of the spatial and temporal nature of self-folding structures are in good agreement with the companion finite element simulations. A simplified reduced-order model is also developed to rapidly and accurately describe the self-folding physics. An important aspect of self-folding is the management of self-collisions, where different portions of the folding structure contact and then block further folding. A metric is developed to predict collisions and is used together with the reduced-order model to design self-folding structures that lock themselves into stable desired configurations.

No MeSH data available.