4D Printing Self-Morphing Structures

Abstract

The main objective of this paper is to introduce complex structures with self-bending/morphing/rolling features fabricated by 4D printing technology, and replicate their thermo-mechanical behaviors using a simple computational tool. Fused deposition modeling (FDM) is implemented to fabricate adaptive composite structures with performance-driven functionality built directly into materials. Structural primitives with self-bending 1D-to-2D features are first developed by functionally graded 4D printing. They are then employed as actuation elements to design complex structures that show 2D-to-3D shape-shifting by self-bending/morphing. The effects of printing speed on the self-bending/morphing characteristics are investigated in detail. Thermo-mechanical behaviors of the 4D-printed structures are simulated by introducing a straightforward method into the commercial finite element (FE) software package of Abaqus that is much simpler than writing a user-defined material subroutine or an in-house FE code. The high accuracy of the proposed method is verified by a comparison study with experiments and numerical results obtained from an in-house FE solution. Finally, the developed digital tool is implemented to engineer several practical self-morphing/rolling structures.

Multi-Trigger Thermo-Electro-Mechanical Soft Actuators under Large Deformations

“…Now, using Equations (10)- (13) and specifying the deformation gradient tensor, the stress and electric displacement vector could be identified.…”

“…Actuators can be triggered by various stimulus such as heat, light, magnetic field, pneumatic pressure, electric filed, pH, and so on [8,9]. Shape-memory alloys, fluidic elastomer actuators, shape memory polymers, dielectric actuators (DEAs), ionic polymer-metal composite, and electro-magnetorheological elastomer actuators are common types of smart materials which could be used in soft actuators [10][11][12][13][14]. In thermal actuators heat is transformed into mechanical work [15].…”

A review on the use of additive manufacturing to produce lower limb orthoses

“…Additive manufacturing minimises material waste and enables the fabrication close to the clients. It allows the fabrication of multi-material components with embedded sensors and morphing components [28][29][30], and it is suitable for the fabrication of products that require customised features, low volume production and/or increased geometric complexity [31]. Seven different technologies can be considered ( Fig.…”

Shape-Adaptive Metastructures with Variable Bandgap Regions by 4D Printing

“…This research is likely to advance the state-of-the-art 4D printing and unlock potentials in the design of functional metastructures for a broad range of applications in acoustic and structural engineering, including sound wave filters and waveguides. much attention due to their lower density, higher recoverable strain of up to 400%, lower cost, simple shape programming procedure, and excellent controllability over the recovery temperature [3,4].In the recent two decades, three-dimensional (3D) printing technology, also known as additive manufacturing (AM), has gained considerable attention as an advanced manufacturing technique that can create complex objects through depositing materials in a layer-by-layer manner [5][6][7][8][9]. With the introduction of active materials, 3D printing approaches have shown excellent potential for the fabrication of adaptive structures, namely four-dimensional (4D) printed structures, with the capability of reshaping their configuration and changing their properties over time [10][11][12].…”

“…This research is likely to advance the state-of-the-art 4D printing and unlock potentials in the design of functional metastructures for a broad range of applications in acoustic and structural engineering, including sound wave filters and waveguides. much attention due to their lower density, higher recoverable strain of up to 400%, lower cost, simple shape programming procedure, and excellent controllability over the recovery temperature [3,4].…”