investigating the feasibility of a proposed model for geometric design of deployable arch structures
deployable scissor type structures are composed of the so-called scissor-like elements (sles), which are connected to each other at an intermediate point through a pivotal connection and allow them to be folded into a compact bundle for storage or transport. several sles are connected to each other in order to form units with regular polygonal plan views. the sides and radii of the polygons are sles. these polygons, in turn, are linked into appropriate arrangements constituting deployable structures, which are either flat or curved in their final deployed configuration. these structures are deployed and demonstrate a huge volume expansion, and this process can be reserved. from a structural point of view, deployable structures have to be designed for two completely different loading conditions, under service loads in the deployed configuration, and during deployment. from a geometric point of view, the whole idea behind this type of deployable structures is based on the sles. because of their numerous advantages, deployable structures have been investigated, designed and constructed by many engineers both for earth and space applications. in the present study the feasibility of a proposed model for geometric design of deployable arch structures has been investigated by abaqus software. the deployable arch presented throughout this work is bi-stable in the sense of being self-standing and stress-free when fully closed or fully deployed, but they represent a high nonlinear geometric behavior during deployment process. the nonlinear behavior of such structures is considered as snap-through behavior. the snap-through phenomenon plays a fundamental role in the efficiency of deployable scissor-type structures; otherwise the structure loses its workability. providing deployability conditions leads to more designing expenses in contrast with ordinary undeployable structures. the additional expenses might be due to sophisticated designing of kinematic connections to guarantee the required deployability. therefore a parametric investigation of the behavior of stated structures under deployment is necessary in order to minimize internal forces. the results indicate that the geometric design methodology for deployable arches of arbitrary curvature, accounting also for the discrete joint size, has been applied successfully for the geometric design of a semi-elliptical arch. verification of deployability has been achieved by deployment simulation with the finite element method. a preliminary structural design indicates the overall feasibility of such an arch with a span of 13.6 m, subjected to dead, snow and wind loads.
investigating the integration of translation technologies into translation programs in iranian universities: basis for a syllabus design in translation technology
today, information technology and computers are indispensable tools of any profession and translation technologies have become an indispensable part of translator’s workstation. with the increasing demands for high productivity and speed as well as consistency and with the rise of new demands for translation and localization, it is necessary for translators to be familiar with market demands an...
abstract nowadays, the science of decision making has been paid to more attention due to the complexity of the problems of suppliers selection. as known, one of the efficient tools in economic and human resources development is the extension of communication networks in developing countries. so, the proper selection of suppliers of tc equipments is of concern very much. in this study, a ...15 صفحه اول
the innovation of a statistical model to estimate dependable rainfall (dr) and develop it for determination and classification of drought and wet years of iran
آب حاصل از بارش منبع تأمین نیازهای بی شمار جانداران به ویژه انسان است و هرگونه کاهش در کم و کیف آن مستقیماً حیات موجودات زنده را تحت تأثیر منفی قرار می دهد. نوسان سال به سال بارش از ویژگی های اساسی و بسیار مهم بارش های سالانه ایران محسوب می شود که آثار زیان بار آن در تمام عرصه های اقتصادی، اجتماعی و حتی سیاسی- امنیتی به نحوی منعکس می شود. چون میزان آب ناشی از بارش یکی از مولفه های اصلی برنامه ...15 صفحه اول
study of cohesive devices in the textbook of english for the students of apsychology by rastegarpour
this study investigates the cohesive devices used in the textbook of english for the students of psychology. the research questions and hypotheses in the present study are based on what frequency and distribution of grammatical and lexical cohesive devices are. then, to answer the questions all grammatical and lexical cohesive devices in reading comprehension passages from 6 units of 21units th...
the effect of using model essays on the develpment of writing proficiency of iranina pre-intermediate efl learners
abstract the present study was conducted to investigate the effect of using model essays on the development of writing proficiency of iranian pre-intermediate efl learners. to fulfill the purpose of the study, 55 pre- intermediate learners of parsa language institute were chosen by means of administering proficiency test. based on the results of the pretest, two matched groups, one as the expe...
a tripartite model of efl teachers attributions, burnout, and self-regulation: towards the prospects of effective teaching
همطالعه حاضر به ارائه مدلی برای آموزش موثر زبان انگلیسی می پردازد. مدل حاضر از سه عامل تاثیر گذار در کارایی تدریس معلمان زبان انگلیسی بهره می برد. این سه عامل شامل سبکهای اسنادی، خود تنطیمی و فرسودگی شغلی معلمان ایرانی زبان انگلیسی می باشد. رساله مورد نظر درچهار فاز طراحی شده است: فاز اول شامل طراحی و رواسازی پرسشنامه سبکهای اسنادی معلمان زبان انگلیسی و فاز دوم شامل استفاده از این پرسشنا...
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نوع سند: پایان نامه
وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی عمران