Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 45 for “"flexures"”.
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Principles and techniques for designing flexures for space applications
Flexures play an important role in precision machine design for space by allowing accurate and repeatable motion through bending of compliant elements. The design of flexures is a non-trivial process due to the interconnection of the kinematics, mechanics, and dynamics. This thesis defines a …
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Design rules and models for the synthesis and optimization of cylindrical flexures
Cylindrical flexures (CFs) are defined as systems composed of flexural elements whose length is defined by the product of their radius of curvature, R, and sweep angle, [phi]. CFs may be constructed out of a cylindrical stock which leads to geometry, manufacturability, and compatibility advantages …
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Design of a three-axis micro-scale metrology system for the characterization of cylindrical flexures
… was achieved in an effort to measure cylindrical flexures such that rules for modeling them might be developed. The system developed measures translations of the flexure normal to the circular surface of the cylinder as well as rotations about the axes within this plane. While numerous metrology …
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Design and fabrication of meso-scale flexural testing apparatus for evaluating aligned CNT composite flexures
… Carbon Nanotube (CNT) based composites in flexures by measuring the kinematics of a composite flexure. The first phase of the research, described in this thesis, is to design, fabricate and assemble a testing apparatus optimized for evaluating aligned CNT based composites. Using existing …
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Design and characterization of tunable stiffness flexural bearings
Compressed flexures have a downwards-tunable stiffness in their compliant directions; their stiffness can theoretically be reduced by up to four orders of magnitude. The compression-stiffiness relation is linear for most of the loading, and this behavior can be taken advantage of to use the flexure …
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Design modeling and fabrication of experimental apparatus for compliant mechanism education kit
… recent developments in the study and design of flexures. Flexure theory can be difficult to explain. This kit is a physical example of the FACT method for designing flexures. The first flexure is a linear motion flexure, which is a familiar design to practicing precision engineers. The second …
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Development of a large displacement flexure based nano-precision XY positioning stage for vacuum environments
Flexures are widely used in precision machines since they offer frictionless, particle-free, and low maintenance operation, and they provide extremely high resolution. Existing flexure-based translation stages usually have motion range to size ratios of less than 0.01 as compared 0.5 or higher in …
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A Compliant Threshold Acceleration Sensor Integrated with Radio Frequency Identifiable Tags
… is introduced to attain thin metal compliant flexures with little variation in the thickness of the compliant flexures. This method allows for a more economical method of producing compliant flexures. The metal bistable mechanism designs presented show significant improvement over the plastic …
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Design of planar-flexure-based contacts for high-repeatability kinematic couplings
… manufacturing processes and metrology systems. Flexures serve to improve the performance of ball-and-flat contacts by preventing motion of the flats in the direction perpendicular to the contacts while allowing motion in tangential directions, thus reducing the effects of friction and wear at …
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The Piezoresistive Effect In Microflexures
… for predicting the piezoresistive effect in microflexures experiencing bending stresses. A linear model describing piezoresistivity exists for members in pure tension and compression. Extensions of this model to more complex loading conditions do not match experimental results. An accurate model …
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Design of a metrology & characterization system for a compliant mechanisms course
… Constraint Topology (FACT), and the new types of flexures that can be designed using this process. The importance of this thesis lies in the benefits compliant mechanisms give to precision engineering. The impact, by improving the quality of designs capable by professional engineers by teaching …
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Design and optimization of x-y-[t̳h̳e̳t̳a̳]z̳, cylindrical flexure stage
Cylindrical flexures (CFs) are composed of curved beams whose length is defined by a radius, R, and a sweep angle, [phi], [1]. The curved nature of the beams results in additional kinematics, requiring additional design rules beyond those used for straight-beam flexures. The curvature also adds …
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Boundary condition effects on vibrating cantilever beams
… With this new information, cantilever style flexures can now be designed to operate in environments which previously would have put them at risk of catastrophic failure, and can allow for three to four times the increased range performance of a compliant mechanism in these environments …
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Framework for Concentrated Strain Deployable Trusses
… Trusses composed of solid rods with rectangular flexures are shown to have significant axial and bending stiffness reductions due to the smaller cross-sectional areas and lower modulus of the flexures. Trusses composed of tubes are less sensitive to this because the flexure cross-sectional area …
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Design, Analysis, and Initial Testing of a Fiber-Optic Shear Gage for 3D, High-Temperature Flows
… instrumentation and strain gages mounted on the flexures for validation of the newer fiber optics. The sensor is constructed of Haynes 230, a high-temperature nickel alloy. The gage housing is made of 316 stainless steel. All components of the gage in pure fiber-optic form can survive to a …
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A large strain piezoelectric microactuator by folding assembly
… been previously demonstrated using mechanical flexures fabricated at the micro scale. This new work presents a method by which that amplification can be increased, along with a method to reduce parasitic out of plane bending present in prior designs. Fabricated actuator triplets demonstrated …
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Piezoceramic Actuated Transducers for Interior Acoustic Noise Control
… The transducer is comprised of three thin flexures that are actuated by piezoceramic material attached to both sides. The flexures actuate a speaker cone that is attached to the end of the flexures. The transducer can act as a sensor or an actuator due to the nature of the piezoceramics. …
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Integrated Piezoresistive Sensing for Feedback Control of Compliant MEMS
… response of polycrystalline-silicon flexures, designing compliant MEMS with integrated piezoresistive sensing using the model, and implementing feedback control using integrated piezoresistive sensing. Integrated piezoresistive sensing is an effective way to produce small, reliable, …
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Mechanical testing of solid materials at the micro-scale
… rectilinear travel characteristics of compound flexures, two novel testing machines have been designed and built to conduct tension, bending and indentation tests in the force regime of 10 pN - 35 N and displacement regime of 20 nm - 6 mm. These machines have been used in measuring the …
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Electromagnetic nanopositioner
… replacement of the conventional metal flexures with rubber bearings, as well as power and sense electronics that can be easily integrated into a compact package. A prototype of this class of nanopositioner with 100,pm of travel and a maximum force output of 460 N was built and tested.
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