19556

۱۹۵۵۶

ﺑﺮرﺳﯽ روشﻫﺎي ﺑﻬﯿﻨﻪﯾﺎﺑﯽ در ﻃﺮاﺣﯽ ﺳﺎزهﻫﺎي ﺗﺎﺷﻮ

كارشناسي ارشد

سازه

۱۳۹۷

۱۳۹۷/۲/۳

دكتر علي كاوه

عمران

ﺳـﺎزهﻫﺎي ﺗﺎﺷـﻮ ﻗﯿﭽﯽﺳـﺎن دﺳﺘﻪاي از ﺳﺎزهﻫﺎي ﻓﻀﺎﮐﺎر ﻣﯽﺑﺎﺷﻨﺪ ﮐﻪ اﻟﻤﺎنﻫﺎي ﻣﯿﻠﻪاي آن دو ﺑﻪ دو ﻫﻤﺎﻧﻨﺪ ﻗﯿﭽﯽ ﺑﻪ ﯾﮑﺪﯾﮕﺮ ﭘﯿﻦ ﺷــﺪهاﻧﺪ. اﯾﻦ ﺳــﺎزهﻫﺎ داراي ﻗﺎﺑﻠﯿﺖ ﺗﻐﯿﯿﺮ ﺷــﮑﻞ از ﺣﺎﻟﺖ ﻓﺸــﺮده )ﺗﺎﺷــﺪه( ﺑﻪ ﺣﺎﻟﺖ ﮔﺴـﺘﺮده )ﺑﺎزﺷـﺪه( ﻣﯽﺑﺎﺷـﻨﺪ. ﻣﺪل ﺳﺎزي اﺗﺼﺎﻻت اﯾﻦ ﺳﺎزهﻫﺎ در ﻧﺮماﻓﺰارﻫﺎي ﺗﺤﻠﯿﻠﯽ ﮐﺎري دﺷﻮار و زﻣﺎنﺑﺮ ﻣﯽﺑﺎﺷـﺪ. ﺑﻪ ﻫﻤﯿﻦ دﻟﯿﻞ در اﯾﻦ ﭘﺎﯾﺎنﻧﺎﻣﻪ روﺷـﯽ ﺑﺮاي آﺳـﺎن ﮐﺮدن ﻓﺮاﯾﻨﺪ ﺗﺤﻠﯿﻞ اﯾﻦ ﺳﺎزهﻫﺎي ﭘﯿﭽﯿﺪه اراﺋﻪ ﺷــﺪه اﺳــﺖ. روش اراﺋﻪ ﺷــﺪه ﺑﺮ اﺳــﺎس ﺗﺤﻠﯿﻞ اﻟﻤﺎن ﻣﺤﺪود ﺑﻪ روش ﺳــﺨﺘﯽ ﻣﯽﺑﺎﺷــﺪ، ﺑﻪ ﮔﻮﻧﻪاي ﮐﻪ ﺑﺮاي اﻟﻤﺎنﻫﺎي ﻗﯿﭽﯽﺳﺎن ﻣﺎﺗﺮﯾﺲ ﺳﺨﺘﯽ وﯾﮋهاي ﺗﻌﺮﯾﻒ ﺷﺪه اﺳﺖ ﮐﻪ ﺑﻪ وﺳﯿﻠﻪي آن ﻣﯽﺗﻮان ﺑﻪ راﺣﺘﯽ ﺳﺎزهﻫﺎي ﺗﺎﺷﻮ ﻗﯿﭽﯽﺳﺎن را ﺗﺤﻠﯿﻞ ﮐﺮد . در ﻗﺴﻤﺖ دﯾﮕﺮ ﭘﺎﯾﺎنﻧﺎﻣﻪ ﺑﻪ ﻃﺮاﺣﯽ ﺑﻬﯿﻨﻪ ﺳﺎزهﻫﺎي ﺗﺎﺷﻮ ﻗﯿﭽﯽﺳﺎن ﭘﺮداﺧﺘﻪ ﺷﺪه اﺳﺖ. در اﯾﻦ ﻗﺴﻤﺖ ﺳﻌﯽ ﺑﺮ آن ﺷـﺪه ﺑﺎ اﺳـﺘﻔﺎده از اﻟﮕﻮرﯾﺘﻢﻫﺎي ﺑﻬﯿﻨﻪﯾﺎﺑﯽ ﻓﺮااﺑﺘﮑﺎري، ﺳﺎزهﻫﺎ ﺑﻪ ﮔﻮﻧﻪ اي ﻃﺮاﺣﯽ ﺷﻮﻧﺪ ﮐﻪ ﺑﻬﯿﻨﻪﺗﺮﯾﻦ وزن و ﺣﺠﻢ را در ﺣﺎﻟﺖ ﺗﺎﺷـﺪه ﺧﻮد داﺷـﺘﻪ ﺑﺎﺷﻨﺪ. ﺑﺮاي دﺳﺖﯾﺎﺑﯽ ﺑﻪ اﯾﻦ ﻫﺪف، ﺳﺎزه در ﺣﺎﻟﺖ ﺑﺎز ﺷﺪه ﺧﻮد ﺗﺤﺖ ﺑﺎرﻫﺎي ﺧﺎرﺟﯽ ﺗﺤﻠﯿﻞ ﻣﯽﺷــﻮد، ﺳــﭙﺲ ﺑﺎ ﺗﻐﯿﯿﺮ ﻣﻘﺎﻃﻊ اﻟﻤﺎنﻫﺎ و ﺷــﮑﻞ ﻫﻨﺪﺳــﯽ ﺳــﺎزه ﺑﻪ ﮐﻤﮏ اﻟﮕﻮرﯾﺘﻢﻫـﺎي ﻓﺮااﺑﺘﮑﺎري، ﺑﻬﯿﻨﻪﺗﺮﯾﻦ ﺣﺎﻟﺖﻫﺎ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻣﺤﺪودﯾﺖﻫﺎي ﻃﺮاﺣﯽ از ﻗﺒﯿﻞ ﺟﺎﺑﺠﺎﯾﯽ ﻣﺠﺎز، ﺗﻨﺶ ﻣﺠﺎز و ﮐﻤﺎﻧﺶ ﺑﺮاي ﺳـﺎزه ﻣﺤﺎﺳـﺒﻪ ﻣﯽﺷﻮﻧﺪ. در اﯾﻦ ﭘﺎﯾﺎنﻧﺎﻣﻪ ﺑﺮاي ﻃﺮاﺣﯽ ﺑﻬﯿﻨﻪ از دو اﻟﮕﻮرﯾﺘﻢ ﻓﺮااﺑﺘﮑﺎري اﺳـﺘﻔﺎده ﺷـﺪه اﺳـﺖ و ﻧﺘﺎﯾﺞ ﺣﺎﺻـﻞ از ﻫﺮ دو اﻟﮕﻮرﯾﺘﻢ ﺑﺎ ﯾﮑﺪﯾﮕﺮ ﻣﻘﺎﯾﺴﻪ MOCBOو NSGAIIﭼﻨﺪ ﻫﺪﻓﻪ ﺷﺪه اﺳﺖ.

1397/07/30

Optimal design of foldable structures

3/21/2019 12:00:00 AM

Foldable structures are one of the space structure’s categories that each pair of its elements are pined like a scissor. These structures are capable to deform from compact form to expanded one. It is difficult and time consuming to modeling the joints of these structures in analysis softwares, so in this proposal presents an analysis method due to easy analysis of these complex structures. The proposed method is based on the stiffness method of finite elements analysis in the way that a stiffness matrix is defined for each scissor element that can present a real model of scissor-link foldable structures. The other part of this proposal is allocated to optimal design of scissor-link foldable structures. In this part, by using meta-heuristic algorithms, it is tried to design structures that have optimum weight and volume in their folded position. To attain this purpose, the structures are modeled under imposed loads then by changing elements cross sections and topology of the structure, the optimum variables are accounted by considering optimization constrains like allowable displacement, maximum stress, and buckling. To get this purpose two multiobjective meta-heuristic algorithms, NSGAII, and MOCBO are used, and the results are compared.