An Actively Controlled Shape-Morphing Compliant Microarchitectured Material

2015 ◽  
Vol 8 (2) ◽  
Author(s):  
Lucas A. Shaw ◽  
Jonathan B. Hopkins

The purpose of this paper is to introduce a new kind of microarchitectured material that utilizes active control to alter its bulk shape through the deformation of its compliant elements. This new kind of microarchitectured material achieves its reconfigurable shape capabilities through a new control strategy that utilizes linearity and closed-form analytical tools to rapidly calculate the optimal internal actuation effort necessary to achieve a desired bulk surface profile. The kind of microarchitectured materials introduced in this paper is best suited for high-precision applications that would benefit from materials that can be programed to rapidly alter their surface or shape by small repeatable amounts in a controlled manner. Examples include distortion-correcting surfaces on which precision optics are mounted, airplane wings that deform to increase maneuverability and fuel efficiency, and surfaces that rapidly reconfigure to alter their texture. In this paper, the principles are provided for optimally designing 2D or 3D versions of the new kind of microarchitectured material such that they exhibit desired material property directionality. The mathematical theory is provided for modeling and calculating the actuation effort necessary to drive these materials such that their lattice shape comes closest to achieving a desired profile. Case studies are provided to demonstrate the utility of this theory and finite-element analysis (FEA) is used to verify the results.

Author(s):  
Lucas A. Shaw ◽  
Jonathan B. Hopkins

The purpose of this paper is to introduce a new kind of actively controlled microarchitecture that can alter its bulk shape through the deformation of compliant elements. This new type of microarchitecture achieves its reconfigurable shape capabilities through a new control strategy that utilizes linearity and closed-form analytical tools to rapidly calculate the optimal internal actuation effort necessary to achieve a desired bulk surface profile. The microarchitectures of this paper are best suited for high-precision applications that would benefit from materials that can be programmed to rapidly alter their surfaces/shape relatively small amounts in a controlled manner. Examples include distortion-correcting surfaces on which precision optics are mounted, airplane wings that deform to increase maneuverability and fuel efficiency, and surfaces that rapidly reconfigure to alter their texture. In this paper, the principles are provided for optimally designing 2D or 3D versions of the new kind of microarchitecture such that they exhibit desired material property directionality. The mathematical theory is provided for modeling and calculating the actuation effort necessary to drive these microarchitectures such that their lattice shape comes closest to achieving a desired profile. Case studies are provided to demonstrate this theory.


2021 ◽  
Vol 160 ◽  
pp. 106874
Author(s):  
Jamal Seyyed Monfared Zanjani ◽  
Pouya Yousefi Louyeh ◽  
Isa Emami Tabrizi ◽  
Abdulrahman Saeed Al-Nadhari ◽  
Mehmet Yildiz

Author(s):  
Luiz T. Souza ◽  
David W. Murray

The paper presents results for finite element analysis of full-sized girth-welded specimens of line pipe and compares these results with the behavior exhibited by test specimens subjected to constant axial force, internal pressure and monotonically increasing curvatures. Recommendations for the ‘best’ type of analytical finite element model are given. Comparisons between the behavior predicted analytically and the observed behavior of the experimental test specimens are made. The mechanism of wrinkling is explained and the evolution of the deformed configurations for different wrinkling modes is examined. It is concluded that the analytical tools now available are sufficiently reliable to predict the behavior of pipe in a manner that was not previously possible and that this should create a new era for the design and assessment of pipelines if the technology is properly exploited by industry.


2017 ◽  
Vol 17 (01) ◽  
pp. 1750011 ◽  
Author(s):  
XUAN ZHANG ◽  
LING WANG ◽  
XIFENG PENG ◽  
DICHEN LI ◽  
JIANKANG HE ◽  
...  

Asphericity and out-of-roundness are generally used to evaluate the manufacturing quality of ultra-high molecular weight polyethylene (UHMWPE) cup inner surfaces, which can potentially affect initial clinical wear and contribute to osteolysis of total hip arthroplasty. This study measured the location and magnitude of asphericity and the out-of-roundness value for four UHMWPE cups in a single set, and then investigated the effects of the asphericity on the contact mechanics of UHMWPE cups. A co-ordinate measuring machine (CMM) was used for the surface measurement and finite element analysis (FEA) was adopted for contact mechanics study. The results demonstrated that the asphericity varied between cups with the maximum value as 0.088[Formula: see text][Formula: see text][Formula: see text]0.004[Formula: see text]mm. Although such a value met the ISO specification, large difference of volume appeared for the asphericity above 0.060[Formula: see text]mm. Actual surface profile accounting for the asphericity was found to affect the value of contact pressure and contact area by around 12%. The inferior asphericity resulted in a nonsmoothly distributed contact pressure, which had a negative effect on the contact mechanics of UHMWPE cups and the edge loading was predicted to occur for the sample with a large asphericity. In conclusion, the asphericity of UHMWPE cup could affect the contact mechanics of the articular bearings and may subsequently contribute to initial wear during bedding-in phase.


1999 ◽  
Vol 121 (1) ◽  
pp. 53-61
Author(s):  
L. T. Souza ◽  
D. W. Murray

The paper presents results for finite-element analysis of full-sized girth-welded specimens of line pipe and compares these results with the behavior exhibited by test specimens subjected to constant axial force, internal pressure, and monotonically increasing curvatures. Recommendations for the “best” type of analytical finite element model are given. Comparisons between the behavior predicted analytically and the observed behavior of the experimental test specimens are made. The mechanism of wrinkling is explained and the evolution of the deformed configurations for different wrinkling modes is examined. It is concluded that the analytical tools now available are sufficiently reliable to predict the behavior of pipe in a manner that was not previously possible and that this should create a new era for the design and assessment of pipelines if the technology is properly exploited by industry.


2007 ◽  
Vol 26-28 ◽  
pp. 953-956 ◽  
Author(s):  
Hong Kyu Kwon ◽  
Kwang Soo Kim

This paper presents our experimentation and modeling efforts to study the pattern of material flow in the extrusion and deposition stages of the Contour Crafting (CC) process. Specifically, we performed a preliminary finite element analysis (FEA) of extrusion and deposition mechanisms with clay as the fabrication material. Using the FEA simulations, we derived certain basic understandings of the effect of extrusion orifice geometry on the performance of CC. We found that a square orifice is most aptly suited, both in terms of delivering the optimal fusion between layers as well as creating the desired external surface profile. Our experiments validate these results.


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