An official website of the United States government
The present study focuses on the mechanical chirality in plate-type topologically interlocked material systems. Topologically interlocked material (TIM) systems are a class of dense architectured materials for which the mechanical response emerges from the elastic behavior of the building blocks and the contact-frictions interactions between the blocks. The resulting mechanical behavior is strongly non-linear due to the stability-instability characteristics of the internal load transfer pattern. Two tessellations are considered (square and hexagonal) and patches from each are used as templates. While individual building blocks are achiral, chirality emerges from the assembly pattern. The measure of \textit{microstructure circulation} is introduced to identify the geometric chirality of TIM systems. TIM systems identified as geometrically chiral are demonstrated to possess mechanical chiral response with a force-torque coupling under transverse mechanical loading of the TIM plate. The chiral length is found to be constant during the elastic response, yet size-dependent. During nonlinear deformation, the chiral length scale increases significantly and again exhibits a strong size dependence. The principle of dissection is introduced to transform non-chiral TIM systems into chiral ones. In the linear deformation regime, the framework of chiral elasticity is shown to be applicable. In the non-linear deformation regime, chirality is found to strongly affect the mechanical behavior more significantly than in the linear regime. Experiments on selected TIM systems validate key findings of the main computational study with the finite element method.
more »
« less
Architectured Materials Mechanics. September 17-19, 2018 , Chicago, IL: Purdue University Libraries Scholarly Publishing Services, 2018.
Architectured materials are an emerging and exciting class of materials with the promise of advantageous performance and multifunctional properties. These materials are characterized by specific and periodic structural features that are larger than what is typically considered a microstructural length scale (such as a grain size) but smaller than the size of the final component made of the architectured material. This class of materials includes but is not limited to lattice materials and cellular material systems, dense material systems composed of building blocks of well-defined size and shape. The key characteristic distinguishing architectured materials from other materials is their very high morphological control, and architectured materials can therefore be considered high information materials. The tight control of the morphological characteristics allows to predefine and control specific mechanisms of local stress transfer, elastic/plastic buckling, gliding of building blocks, or propagation of cracks along predefined paths. Well-designed architectured materials can generate new and attractive combinations of properties that can be programmed in the material. In particular, the empty spaces and gliding interfaces contained in architectured materials can be exploited to overcome the theoretical bounds that apply to monolithic materials. This IUTAM symposium provides a state of the art on the engineering science of architectured materials and focus on the mechanics, design, fabrication, and mechanical performance of all categories of architectured materials including but not limited to lattice materials, metamaterials, and topologically interlocked materials.
more »
« less
- Award ID(s):
- 1820220
- PAR ID:
- 10087572
- Date Published:
- Journal Name:
- Proceedings of the IUTAM Symposium Architectured Materials Mechanics
- Page Range / eLocation ID:
- https://docs.lib.purdue.edu/iutam/
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract The present study is concerned with the deformation response of an architectured material system, i.e., a 2D-material system created by the topological interlocking assembly of polyhedra. Following the analogy of granular crystals, the internal load transfer is considered along well-defined force networks, and internal equivalent truss structures are used to describe the deformation response. Closed-form relationships for stiffness, strength, and toughness of the topologically interlocked material system are presented. The model is validated relative to direct numerical simulation results. The topologically interlocked material system characteristics are compared with those of monolithic plates. The architectured material system outperforms equivalent size monolithic plates in terms of toughness for nearly all possible ratios of modulus to the strength of the material used to make the building blocks and plate, respectively. In addition, topologically interlocked material systems are shown to provide better strength characteristics than a monolithic system for low strength solids.more » « less
-
Abstract Kirigami, the ancient paper art of cutting, has recently emerged as a new approach to construct metamaterials with novel properties imparted by cuts. However, most studies are limited to thin sheets‐based 2D kirigami metamaterials with specific forms and limited reconfigurability due to planar connection constraints of cut units. Here, 3D modular kirigami is introduced by cutting bulk materials into spatially closed‐loop connected cut cubes to construct a new class of 3D kirigami metamaterials. The module is transformable with multiple degrees of freedom that can transform into versatile distinct daughter building blocks. Their conformable assembly creates a wealth of reconfigurable and disassemblable metamaterials with diverse structures and unique properties, including reconfigurable 1D column‐like materials, 2D lattice‐like metamaterials with phase transition of chirality, as well as 3D frustration‐free multilayered metamaterials with 3D auxetic behaviors and programmable deformation modes. This study largely expands the design space of kirigami metamaterials from 2D to 3D.more » « less
-
In supramolecular materials, multiple weak binding groups can act as a single collective unit when confined to a localized volume, thereby producing strong but dynamic bonds between material building blocks. This principle of multivalency provides a versatile means of controlling material assembly, as both the number and the type of supramolecular moieties become design handles to modulate the strength of intermolecular interactions. However, in materials with building blocks significantly larger than individual supramolecular moieties (e.g., polymer or nanoparticle scaffolds), the degree of multivalency is difficult to predict or control, as sufficiently large scaffolds inherently preclude separated supramolecular moieties from interacting. Because molecular models commonly used to examine supramolecular interactions are intrinsically unable to examine any trends or emergent behaviors that arise due to nanoscale scaffold geometry, our understanding of the thermodynamics of these massively multivalent systems remains limited. Here we address this challenge via the coassembly of polymer-grafted nanoparticles and multivalent polymers, systematically examining how multivalent scaffold size, shape, and spacing affect their collective thermodynamics. Investigating the interplay of polymer structure and supramolecular group stoichiometry reveals complicated but rationally describable trends that demonstrate how the supramolecular scaffold design can modulate the strength of multivalent interactions. This approach to self-assembled supramolecular materials thus allows for the manipulation of polymer−nanoparticle composites with controlled thermal stability, nanoparticle organization, and tailored meso- to microscopic structures. The sophisticated control of multivalent thermodynamics through precise modulation of the nanoscale scaffold geometry represents a significant advance in the ability to rationally design complex hierarchically structured materials via self-assembly.more » « less
-
Bridging the current gap between the precision and efficiency demonstrated by natural systems and synthetic materials requires interfacing and independently controlling multiple stimuli-responsive building blocks in a single platform. The mentioned orthogonal control over material properties (i.e., the ability to selectively activate one stimuli-responsive moiety without affecting another) could pave the way for a multitude of applications, including logic-gated optoelectronics, on-demand drug delivery platforms, and molecular shuttles, for example. In this Review, we highlight the recent successful strategies to achieve orthogonal control over material properties using a combination of stimuli-responsive building blocks and multiple independent stimuli. We begin by surveying the fundamental studies of multi-stimuli-responsive systems, which utilize a variety of stimuli to activate a single stimuli-responsive moiety (e.g., spiropyran, diarylethene, or dihydroazulene derivatives), because these studies lay the foundation for the design of systems containing more than one independently controlled fragment. As a next step, we overview the emerging field focusing on systems which are composed of more than one unique stimuli-responsive unit that can respond to independent stimuli, including distinct excitation wavelengths, or a combination of light, heat, pH, potential, or ionic strength. Recent advances clearly demonstrate how strategic coupling of orthogonally controlled stimuli-responsive units can allow for selective modulation of a range of material properties, such as conductivity, catalytic performance, and biological activity. Thus, the highlighted studies foreshadow the emerging role of materials with orthogonally controlled properties to impact the next generation of photopharmacology, nanotechnology, optoelectronics, and biomimetics.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Conference Paper:
- The DOI is not currently available.
