Les structures pliées intéressent architectes et ingénieurs pour leurs qualités structurelles autant que spatiales et plastiques. En prenant comme point de départ la bande rectiligne pliée, ce travail de recherche aborde non pas la conception de surfaces plissées mais celle de structures réticulées. La conception de structures “à trous” à partir de bandes pliées constitue un angle d’approche original. La notion de continuité induite par le pli transforme la manière de concevoir la structure réticulée, habituellement caractérisée par des nœuds et barres dissociés. L’emploi de bandes continues rectilignes est une approche possible pour rationaliser la conception de formes complexes en minimisant la quantité de chutes de matière. Cette recherche explore de nouvelles méthodes de conception des formes courbes. Les objectifs de cette recherche sont :- la classification des différentes approches possibles dans la conception à partir de bandes rectilignes pliées- l'étude d'éléments modulaires pliés dont l’assemblage permet la génération de surfaces courbes variables: la géométrie de différentes configurations de bandes pliées sera décrite ainsi que les assemblages autorisés / Folded structures are attractive to architects and engineers for their structural qualities as well as spatial and plastic qualities. Taking as a starting point a linear folded stripe, this research does not address the design of pleated surfaces but that of reticular structures. The design of structures with "holes" from folded stripes is an original angle of approach. From a conceptual point of view, the continuity caused by folds transforms the usual conception by separated nodes and bars of reticular structures. The use of continuous linear stripes is one possible approach to make more efficient the design of complex shapes by minimizing the produced offcuts. This research investigates new methods of designing curved shapes. The aims of this research are:- A classification of different possible approaches encountered when conceiving from folded stripes.- The study a modular folded elements which assembly allows the generation of various curved surfaces : the geometry of different configurations of folded stripes and the assemblies allowed will be described

"Microelectromechanical systems (MEMS) are integrated mechanical and electrical devices that are fabricated with features micrometers in size. MEMS are used as chemical laboratories on a chip, actuators, sensors, etc. To increase their operational capability, various MEMS sensors are being integrated into sensor systems, whose functionality may not decrease when their size decreases. However, before more advancement can be made in the sensor systems, behavior of individual sensors must be better understood. Without the basic knowledge of how and why MEMS sensors react the way they do, it is impossible to determine how MEMS sensor systems will behave. Out of the many sensors that can be included in the system, a MEMS gyroscope was selected for consideration in this paper. More specifically, the effects that suspension has on the topography of the microgyroscopes were studied. In this thesis, the folded springs that support the MEMS gyroscopes were modeled using analytical and computational methods, whose results were verified using experimentation. The analytical results correlated well with the computational and experimental results. The analytical and computational results for the deformations of the cantilever compared within 0.1%. The differences between the analytical and experimental results were on the order of 10%. Knowledge gained from these studies will help in the development of a through methodology for modeling the microgyroscope. This methodology will facilitate insertion of the microgyroscopes into the sensor systems."

Analog-to-digital converters are inevitable in the modern communication systems and there is always a need for the design of low-power converters. There are different A/D architectures to achieve medium resolution at medium speeds and among all those Cyclic/Algorithmic structure stands out due to its low hardware complexity and less die area costs. This thesis aims at discussing the ongoing trend in Cyclic/Algorithmic ADCs and their functionality. Some design techniques are studied on how to implement low power high resolution A/D converters. Also, non-ideal effects of SC implementation for Cyclic A/D converters are explored. Two kinds of Cyclic A/D architectures are compared. One is the conventional Cyclic ADC with RSD technique and the other is Cyclic ADC with Correlated Level Shift (CLS) technique. This ADC is a part of IMST Design + Systems International GmbH project work and was designed and simulated at IMST GmbH. This thesis presents the design of a 12-bit, 1 Msps, Cyclic/Algorithmic Analog-to-Digital Converter (ADC) using the “Redundant Signed Digit (RSD)” algorithm or 1.5-bit/stage architecture with switched-capacitor (SC) implementation. The design was carried out in 130nm CMOS process with a 1.5 V power supply. This ADC dissipates a power of 1.6  mW when run at full speed and works for full-scale input dynamic range. The op-amp used in the Cyclic ADC is a two-stage folded cascode structure with Class A output stage. This op-amp in typical corner dissipates 631 uW power at 1.5 V power supply and achieves a gain of 77 dB with a phase margin of 64° and a GBW of 54 MHz at 2 pF load.

Novel and low-cost antennas suitable for WLAN access points are presented. The operating bandwidths of the proposed antennas can cover the 2.4/5.2/5.8 GHz WLAN bands, and the antenna gain is larger than 2 and 4 dBi in the 2.4 and 5 GHz bands; respectively. Besides, they can also generate the good omnidirectional radiation patterns in the azimuthal plane. Dipole antenna, folded dipole antenna, monopole antenna and circularly polarized antenna has been applied in the proposed designs, and good antenna performance has been obtained.

A novel approach to miniaturizing an 802.11b WLAN card using folded-flex ultra-thin substrates is presented. A 73 percent reduction in size was realized using hybrid circuits on FR4 and polyimide. There is even more potential for further reduction if more copper layers are used. The miniaturized 802.11b WLAN cards were used to design 802.11b wireless sensor nodes. A research test-bed was setup to study how 802.11b networked sensor nodes could operate in the field. There are many applications for such sensor networks like habitat monitoring, object tracking, seismic detection, military surveillance, or fire detection to name a few. This investigation focuses on the requirements, design, and performance of a miniaturized 802.11b wireless LAN sensor node that is reliable, can be deployed in large-scale, and has the endurance long-lived for surveillance applications. An aperture coupled microstrip antenna is investigated for 2.44 GHz wireless local area networks (WLAN) which has the advantages of being low-profile and compact. The most important parameters for antenna optimization have been determined through extensive simulation using Ansoft's HFSS and experimental verification. As a result, an omnidirectional antenna with a size of 36.2 mm x 32 mm x 4.75 mm has been realized using Rogers 5880 duroid (permittivity = 2.20 ; loss tangent = 0.0004) with 4.4 dBi of gain, > 80 MHz, and a return loss > -32 dB. These types of performance characteristics make the antenna highly desirable for both 802.11b and Bluetooth applications.

abstract: QR decomposition (QRD) of a matrix is one of the most common linear algebra operationsused for the decomposition of a square/non-square matrix. It has a wide range of applications especially in Multiple Input-Multiple Output (MIMO) communication systems. Unfortunately it has high computation complexity { for matrix size of nxn, QRD has O(n3) complexity and back substitution, which is used to solve a system of linear equations, has O(n2) complexity. Thus, as the matrix size increases, the hardware resource requirement for QRD and back substitution increases signicantly. This thesis presents the design and implementation of a exible QRD and back substitution accelerator using a folded architecture. It can support matrix sizes of 4x4, 8x8, 12x12, 16x16, and 20x20 with low hardware resource requirement. The proposed architecture is based on the systolic array implementation of the Givens algorithm for QRD. It is built with three dierent types of computation blocks which are connected in a 2-D array structure. These blocks are controlled by a scheduler which facilitates reusability of the blocks to perform computation for any input matrix size which is a multiple of 4. These blocks are designed using two basic programming elements which support both the forward and backward paths to compute matrix R in QRD and column-matrix X in back substitution computation. The proposed architecture has been mapped to Xilinx Zynq Ultrascale+ FPGA (Field Programmable Gate Array), ZCU102. All inputs are complex with precision of 40 bits (38 fractional bits and 1 signed bit). The architecture can be clocked at 50 MHz. The synthesis results of the folded architecture for dierent matrix sizes are presented. The results show that the folded architecture can support QRD and back substitution for inputs of large sizes which otherwise cannot t on an FPGA when implemented using a at architecture. The memory sizes required for dierent matrix sizes are also presented. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2020

Integral abutment bridges are very common for short span bridges in the United State due to their less construction and maintenance cost and generally good performance. This thesis studies the first integral abutment bridge using Folded Plate Girder (FPG) Bridge System. The bridge is instrumented with a variety of gauges to capture the behavior of the bridge, and a total of two year and one month [11/2011~12/2013] of data are collected and long-term data monitoring is performed. Live load test and long term temperature effect on the bridge are studied using finite element modeling and compared with actual field data. Girder strain/stress at mid-span and quarter-span and abutment rotations were investigated. From the result, first the bridge was found to show good performance. Shear lag effect was found to be happening at the bottom flange-to-web junction of the steel girder when subjected to concentrated loading. Thermal gradient was found to be significant on the girder strain and abutment rotations.

No description available.

Origami can be a powerful source of design inspiration in the creation of reconfigurable systems with unparalleled performance. This thesis provides fundamental tools for designers to employ as origami-based designs are pursued in their respective fields of expertise. The first chapter introduces origami and makes connections between origami and engineering design through a survey of engineered applications and characterizing the relationship between origami and compliant mechanisms. The second chapter evaluates the creasing of non-paper sheet materials, such as plastics and metals, to facilitate origami-based compliant mechanism design. Although it is anticipated that most origami-based design will result from surrogate folds (indirect methods of replacing the crease), it is valuable to provide information that may help in more direct approaches for origami-based design in materials other than paper. Planar sheets of homogeneous material are considered as they maintain the principles fundamental to origami (flat initial state, low cost, readily available). The reduced stiffness along the axis of the crease is an enabling characteristic of origami. Hence a metric based on the deformation of the crease compared to the deformation of the panels enables engineering materials to be evaluated based on their ability to achieve the "hinge-like" behavior observed in folded paper. Advantages of both high and low values of this metric are given. Testing results (hinge indexes, residual angles, localized hinge behavior and cyclic creasing to failure) are presented for various metals and polymers. This methodology and subsequent findings are provided to enable origami-based design of compliant mechanisms. The third chapter proposes a basic terminology for origami-based design and presents areas of considerations for cases where the final engineering design is directly related to a crease pattern. This framework for navigating from paper art to engineered products begins once the crease pattern has been selected for a given application. The four areas of consideration are discussed: 1) rigid foldability 2) crease characterization 3) material properties and dimensions and 4) manufacturing. Two examples are concurrently presented to illustrate these considerations: a backpack shell and a shroud for an adjustable C-Arm x-ray device used in hospitals. The final chapter provides concluding remarks on origami-based design.

No description available.