
NSF Org: |
CMMI Division of Civil, Mechanical, and Manufacturing Innovation |
Recipient: |
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Initial Amendment Date: | September 11, 2012 |
Latest Amendment Date: | September 11, 2012 |
Award Number: | 1235532 |
Award Instrument: | Standard Grant |
Program Manager: |
kara peters
CMMI Division of Civil, Mechanical, and Manufacturing Innovation ENG Directorate for Engineering |
Start Date: | September 15, 2012 |
End Date: | August 31, 2016 (Estimated) |
Total Intended Award Amount: | $373,453.00 |
Total Awarded Amount to Date: | $373,453.00 |
Funds Obligated to Date: |
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History of Investigator: |
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Recipient Sponsored Research Office: |
3100 MARINE ST Boulder CO US 80309-0001 (303)492-6221 |
Sponsor Congressional District: |
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Primary Place of Performance: |
3100 Marine Street, Room 481 Boulder CO US 80303-1058 |
Primary Place of
Performance Congressional District: |
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Unique Entity Identifier (UEI): |
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Parent UEI: |
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NSF Program(s): |
ESD-Eng & Systems Design, Mechanics of Materials and Str |
Primary Program Source: |
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Program Reference Code(s): |
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Program Element Code(s): |
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Award Agency Code: | 4900 |
Fund Agency Code: | 4900 |
Assistance Listing Number(s): | 47.041 |
ABSTRACT
The research objective of this grant is to elucidate the fundamental mechanisms that are responsible for contact, adhesion, and friction interactions between micro-patterned surfaces and soft fluid-coated substrates. The goal is to understand the generation of tractions; its dependence of key design, environmental, and operational parameters; and its impact on the mechanical response of the substrate. A multi-scale modeling framework will be used to capture the interplay of large macro- and micro-scale deformation phenomena during the roll-over of a treaded wheel over a soft wet substrate, in dependence of material, geometric, and operational parameters. The mechanical behavior of tread and substrate will be described by large deformation theories and appropriate constitutive models. The tight integration of modeling and experiments will provide novel insight into the contact mechanics of soft, wet materials, in particular into the microscopic phenomena for generating friction and the interplay of macro- and micro-scale mechanics for generating traction.
If successful, this research will facilitate the discovery of new types of patterned architectures and concepts and establish a crucial body of knowledge needed for the design of in vivo robotic devices that can reduce patient trauma and expand robotic surgery. The proposed educational program will introduce students at all levels, including those from typically underrepresented groups, to the excitement inherent in research conducted at the intersection of micro-fabrication, biomechanics, and robotics in general, and to the promise inherent in the world of surgical robotics specifically. The proposed educational activities will be enhanced by our access to the University of Colorado?s Award-winning Integrated Teaching and Learning Laboratory.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The main goals of this project were to: 1) study the tread-surface interaction between polymer micro-patterned treads and soft, self-lubricating substrates, 2) elucidate the fundamental mechanisms that are responsible for contact, adhesion, and friction interactions between micro-patterned surfaces and soft fluid-coated substrates, 3) explore mechanical and electrical designs for in vivo robotic surgery devices, 4) develop methods to complete experimental studies with 3D printed treads and soft polymer, hydrogel, or real gastrointestinal tissue substrates, 5) study, and understand, the generation of tractions, its dependence of key design, environmental, and operational parameters, and its impact on the mechanical response of the substrate, 6) develop and implement novel numerical methods to analyze the complex scenario of fluid-structure-structure interaction and contact, and 7) investigate the little researched regime of surface contact and adhesion with highly nonlinear, soft structures and foams.
Significant experimental results have included pillar traction performance prediction modeled and verified using an automated traction measurement platform and pillar adhesion measurement data collected and verified using novel contact and separation methods. Adhesion and separation mechanics models were modified to incorporate necessary experimental deviations from convention mechanics.
Significant numerical modeling results have included a novel Arbitrary Eulerian-Lagrangean (ALE) eXtended Finite Element Method (XFEM) framework for fully coupled fluid-structure interaction problem based on an immersed boundary formulation. The accuracy and robustness of this framework was tested through comparison with benchmark results, obtained with body-fitted meshes. The ALE XFEM framework, integrated into an explicit level set topology optimization method, allows for optimizing both the external and internal layout of the structure. The accuracy of the XFEM solution along the fluid-structure interface allows considering a broad range of design criteria in the formulation of the optimization problem, such as the maximum shear stress in the fluid. Using XFEM approach for contact problems, we were able – for the first time – to solve topology optimization problems accounting for bi-lateral contact. Initially, our approach was restricted to small strains, but later expanded onto finite strain models.
Last Modified: 11/17/2016
Modified by: Mark E Rentschler
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