Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form

An Investigation in Structural Shape Morphing by Modulus Variation

Mohaghegh Motlagh, Seyed Amin (2014) An Investigation in Structural Shape Morphing by Modulus Variation. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

PDF (Motlagh,SA_ETD2013)
Primary Text

Download (6MB) | Preview


This work addresses structural shape morphing, defined as change of shape due to modulus manipulation. The goal is to incorporate variable-modulus materials into a structure, and utilize the controllable modulus change to enhance the ability to morph the structure with limited actuator numbers, locations, and force levels to desired shapes that could not be achieved in the native structure. A significant portion of the work is to demonstrate the capability of the proposed strategy to broaden the space of achievable shapes within the elastic range. In order to quantify the morphed shapes, a specific planar structure with defined boundary condition is used as the model. The focus of this study is not the temporal change of the material’s phase or the structure’s shape, but rather the resulting shape of the structure due to modulus change and applied force.
The problem of inverse morphing is thoroughly investigated; that is, finding the spatial distribution of elastic modulus values and the actuation forces that produce a desired shape and minimize the shape error cost function. Genetic algorithm is used to solve this inverse problem.
Finally, a numerical algorithm to solve the morphing of an arbitrary structure is proposed. In this algorithm, computational and numerical programs are interchangeably used to build the structure’s model and to solve the shape morphing problem. As a case study, a practical device is selected, drawn from a hydrokinetic energy harvesting application, and a 2D model is created. The structure’s shape change due to modulus manipulation is numerically investigated. At the end, path-dependency in sequential shape morphing has been explored in a mass-spring model as well as in the example structure.


Social Networking:
Share |


Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Mohaghegh Motlagh, Seyed
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairClark, Williamwclark@pitt.eduWCLARK
Committee MemberCole, Danieldcc20@pitt.eduDCC20
Committee MemberVipperman, Jeffreyjsv@pitt.eduJSV
Committee MemberBrigham, JohnBrigham@pitt.eduBRIGHAM
Date: 29 January 2014
Date Type: Publication
Defense Date: 31 October 2013
Approval Date: 29 January 2014
Submission Date: 4 December 2013
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 170
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Mechanical Engineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Structural Shape Morph, Optimization, Genetic Algorithm (GA), Finite Element Analysis, Inverse Solution, Variable-modulus Structures
Date Deposited: 29 Jan 2014 18:53
Last Modified: 15 Nov 2016 14:16


Monthly Views for the past 3 years

Plum Analytics

Actions (login required)

View Item View Item