京都大学 / 新制・課程博士 / 博士(工学) / 甲第24642号 / 工博第5148号 / 新制||工||1983(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 大嶋 正裕, 教授 竹中 幹人, 教授 佐野 紀彰 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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Stable Unbonded Fibre Reinforced Elastomeric Isolators (SU-FREI) have been investigated extensively for seismic applications, with over 20 years of literature supporting their use in isolation of structures as an alternative to conventional Steel Reinforced Elastomeric Isolators (SREI). Preliminary investigations have been conducted into their potential use as bridge bearings, where they could provide an alternative to unreinforced and steel reinforced elastomeric bearings. SU-FREI offer a number of potential advantages in this application relative to SREI, including compactness due to thinner reinforcement layers, ease of installation, rotational tolerances, and ease of manufacture. Recently, SU-FREI have been installed under certain highway bridges along the 407 ETR where the previous unreinforced elastomeric bearings had experienced failure. Monitoring has been conducted by Associated Engineering for the 407 ETR Corporation. Data was collected from this monitoring program and field visits have been conducted to observe the condition of the bearings. The original design process used for the SU-FREI bearings has also been reviewed. The monitoring data was compared against design calculations, and the behavior of the SU-FREI analysed to determine whether they meet performance expectations and are suitable for further use as bridge bearings. It was found that some SU-FREI had experienced degradation, including the appearance of an unidentified liquid. The causes of deterioration were investigated and postulated to be primarily related to design limitations imposed by the geometry of the bridges, original design calculation assumptions, and installation issues. Where these factors were not present, the SU-FREI bearings were found to have experienced little to no deterioration. Furthermore, it was determined through comparative design calculations that the FREI outperformed equivalent SREI with regard to rotational capacity. Recommendations have been developed for future deployment of SU-FREI as bridge bearings. Based on the results of initial deployments, larger-scale employment of SU-FREI in this application should be considered. / Thesis / Master of Applied Science (MASc) / Concrete and steel bridges deform due to temperature changes, traffic motion, and other factors. To allow these deformations without inducing large forces or damage, bearings are employed between the bridge deck and supports. One type of bearing consists of alternating layers of rubber and steel: steel strengthens the bearing, while the rubber provides lateral and rotational flexibility. A relatively new type of bearing has been developed and tested that replaces the steel layers with carbon fibre. Recently, several of these new SU-FREI bearings have been installed on actual highway bridges. The focus of this thesis is on the performance of SU-FREI installed as bridge bearings. The goal was to observe their performance, identify any unexpected behavior, and create recommendations for future consideration whenever SU-FREI are to be used as bridge bearings. Generally, it was found that their performance is satisfactory provided they are designed and used appropriately.

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Orthodox optical devices, such as lenses, mirrors, and prisms, are composed of solidstate materials, which although well studied and implemented ubiquitously are severely limited in their adaptable properties. An arguably new field of adaptive optics has emerged to further expand photonic manipulation competences of optical components. Fluid-based adaptive optical components were introduced as early as 1968 [1]; such components have the ability to change the shape of their interface surface, thus allowing for a variable curvature profile. The method of manipulation varies greatly, as does the range of surface deformations. A solid-state optical component is affected by system vibration variation only (difference in vibration from one component to the other due to damping effect). By comparison, two large limiting factors of a fluid-based adaptive optical component are the effect of local vibrations on the surface of the device and gravitational effect (when the optical axis of a lens is positioned parallel to gravitational pull). Such a gravitational effect has been mitigated by the invention of the mechanical electrowetting lens [2], which uses density matching of two liquids that make up an adaptive lens. However, this configuration creates an extra limiting factor of density matching two optically clear fluids with a desirable transmission spectrum. This method can also become bulky when a large aperture is needed. In this thesis, two adaptive lens systems are explored. Principles of operation, performance, limitations, as well as future improvements are studied and theorized. iv The first lens uses an optically clear elastomer as the substrate of an adaptive lens and a primitive mechanical manipulation to turn a plano–plano lens into a plano–convex lens. The second lens is composed of an optically clear gel rather than a fluid. Both methods exhibit excellent optical properties regardless of the orientation about the gravitational pull and significantly limit local vibration affects simply by the physical nature of the chosen materials.

Controlling the specific adhesive properties of surfaces is a technologically complex challenge that has piqued the interest of many research groups around the world. While many scientists have used complex topographic and chemically altered surfaces to tune adhesion, others have shown that naturally occurring phenomena, such as elastic instabilities, can impact adhesion. We provide a thorough investigation into the effects of periodic surface buckling instabilities, or wrinkles, on adhesion. Wrinkles are an attractive surface patterning alternative as they form spontaneously over large areas and their dimensions, namely wavelength and amplitude, can be controlled on length scales relevant for adhesion control. We focus on the development of fundamental relationships that relate wrinkle adhesion to materials properties and topographic feature geometry. To accomplish this goal, we first investigate the separation of a flat rigid punch from a single elastic cylinder, which models the separation of a single wrinkle. The knowledge gained from this study is then utilized to develop a scaling expression relating adherence force to wrinkle geometry, materials properties, and testing geometry. This scaling theory is validated by varying these parameters systematically in a series of model wrinkle adhesion experiments. Added complexity in the form of varied crosslinker density, which alters the ratio of storage to loss moduli, and geometric confinement effects on wrinkle adhesion are then studied. Finally, a novel technique for fabricating biaxial wrinkles with two independently-adjusted wavelengths is developed, adding an additional parameter which can be tuned to further control adhesion. A single elastic cylinder was probed with a finite rigid flat probe, allowing the separation mechanism of a single "macro" scale wrinkle to be determined. Rather than a long cylinder contact mechanism, which has been utilized in describing wrinkle adhesion mechanisms in the past, an elliptical contact area approximation was found to more appropriately describe the single cylinder adhesion data. To consider the impact of an array of cylinders on adhesion, a model wrinkle system comprised of an elastomeric foundation and chemically-simple polymer film was developed. The wrinkle wavelength, amplitude, substrate modulus, and probe radius were varied, and the normal adhesive response of each aligned wrinkled surface was determined. Overall, wrinkles were found to decrease the separation force relative to a smooth surface and the separation force varied inversely with the square root of a wrinkle dimension, either wavelength or amplitude. The effects of viscoelasticity on the adhesion of a wrinkled substrate that is geometrically confined was studied. Wrinkled surface features were molded onto the surface of a rigid cylindrical probe, and the normal adhesion of these probes contacting thin elastomeric films fabricated with varying crosslinker concentrations was measured. The materials-defined length scale relating adhesion energy and modulus controlled the wrinkle feature sizes that impacted the adhesive response of each smooth film. In the most highly crosslinked films, small wrinkles increased both the separation force and adhesion energy of the interface two-fold, while large wrinkles reduced adhesion to almost nothing. Capitalizing on knowledge gained in the fabrication of many wrinkled surfaces, a novel technique for fabricating biaxial wrinkles was developed. Aligned wrinkles were formed on a partially crosslinked substrate, the modulus of the substrate was increased by allowing the material to crosslink completely, and a mechanical compressive strain was then imposed orthogonal to the primary wrinkle direction. This process resulted in the formation of biaxial wrinkled surfaces with two distinct, independently controlled lateral dimensions or wavelengths.

Silicone stands as an indispensable material for numerous applications; however, its high energy-cost synthesis poses significant environmental challenges. To address these concerns, bio-based silicone has gained considerable attention, showcasing its potential to dilute energy density while offering inherent functional benefits. Despite promising prospects, existing incorporation methods often involve protecting groups, rare metal catalysts, and multistep synthesis, which contradict green chemistry principles. The aza- Michael reaction emerges as a superior choice due to its high atom economy and mild reaction conditions. However, it still suffers from prolonged reaction times, hindering its overall efficiency and sustainability. This thesis utilizes self-activated beta-hydroxy acrylates to greatly enhance aza-Michael kinetics, achieving a 3-fold rate enhancement in solvent-free silicone synthesis. This fast aza-Michael reaction acts as the platform for the incorporation of Vitamin C and amino acids into silicone materials. Vitamin C-modified silicone demonstrates the potential for controlled antioxidant activity release, while amino acid-functionalized silicones are synthesized using choline amino acid ionic liquids, presenting a protecting-group-free and solvent-free synthesis method. Moreover, the synthesized choline amino acid-functional polymers and elastomers are investigated for their dielectric properties revealing promising potential for dielectric elastomer actuator applications. These innovative methods offer green alternatives for incorporating hydrophilic biomolecules into hydrophobic silicone systems, providing new functionalities that address both environmental and functional requirements. / Thesis / Doctor of Science (PhD)