This degree project is the final part of the bachelor in mechanical engineering at Linnaeus University in Växjö. The project has been accomplished at ALT Hiss AB in Alvesta. The company manufactures hydraulic elevators, less traction elevators and escalators. The purpose of this thesis has been to design a tool that plumbs the elevator shaft. The thesis has been completed with literature studies, interviews and data collections. The final concept sketch and idea drawing is presenting the result.

When compared to traditional concrete, steel fibre reinforced concrete (SFRC) shows several enhancements in performance, including improved tensile resistance, toughness and ductility. One potential application for SFRC is in columns where the provision of steel fibres can improve performance under axial and lateral loads. The use of SFRC can also allow for partial replacement of transverse reinforcement required by modern seismic codes. To improve workability, self-consolidating concrete (SCC) can be combined with steel fibres, leading to highly workable SFRC suitable for structural applications. Recent advances in material science have also led to the development of ultra-high performance fibre reinforced concretes (UHPFRC), a material which exhibits very high compressive strength, enhanced post-cracking resistance and high damage tolerance. In heavily loaded ground-story columns, the use of UHPFRC can allow for reduced column sections. This thesis presents the results from a comprehensive research program conducted to study the axial behaviour of columns constructed with highly workable SFRC and UHPFRC. As part of the experimental program, twenty-three full-scale columns were tested under pure axial compressive loading. In the case of the SFRC columns, columns having rectangular section and constructed with SCC and steel fibres were tested, with variables including fibre content and spacing of transverse reinforcement. The results confirm that use of fibres results in improved column behaviour due to enhancements in core confinement and cover behaviour. Furthermore, the results demonstrate that the provision of steel fibres in columns can allow for partial replacement of transverse reinforcement required by modern codes. The analytical investigation indicates that confinement models proposed by other researchers for traditional RC and SFRC can predict the response of columns constructed with SCC and highly workable SFRC. In the case of the UHPFRC columns, variables included configuration and spacing of transverse reinforcement. The results demonstrate that the use of appropriate detailing in UHPFRC columns can result in suitable ductility. Furthermore, the results demonstrate the improved damage tolerance of UHPFRC when compared to traditional high-strength concrete. The analytical investigation demonstrates the need for development of confinement models specific for UHPFRC.

The objective of this research project was to simulate the behavior of armor metals at high strain rates and large strains, using the Johnson-Cook visco-plastic model, while incorporating the formation of adiabatic shear bands. The model was then to be applied to three armor metals, namely maraging steel 300, high hardness armor (HHA), and aluminum alloy 5083-H131; supplied by the Canadian Department of National Defense and tested in compression at the University of Manitoba. The Johnson-Cook model can accurately simulate the behavior of BCC metal (steels) up to a point of thermal instability. Conditions for complete shear failure in the model match closely to conditions at which adiabatic shear bands formed in specimens tested experimentally. The Johnson-Cook model is not quite valid for FCC metals, such as aluminum, where strain rate and temperature effects are dependent on the strain while in the Johnson-Cook model, these parameters are separable.

Refiners are used in the pulp and paper industry to separate wood chips into individual fibres and to develop the morphology of fibres to be suitable for the type and grade of paper to be produced. Within a refiner are discs, at least one of which rotates at high speed and all of which are lined with radial patterns of bars on their opposing surfaces. As the chips and fibres are accelerated through the refiner, compressive and shear forces are applied to them by the bars as the opposed discs cross each other. Experiments have shown that the contact mechanics of bar-crossings are a significant factor in the development of fibre properties. To investigate the contact mechanics in operating refiners, a prototype piezoelectric-based sensor was developed to measure the forces applied by the bars. This work re-designs the prototype sensor to function at the mill-scale, and validates the design in two trials. Performance during these trials is presented along with an in-depth analysis of the recorded data. Arrays of force sensors were installed in two single-disc refiners: a pilot-scale machine operating as a primary stage, and a mill-scale machine operating as a rejects stage. In the rejects refiner, mean forces were highest at the periphery of the refining zone, while in the primary stage, mean forces were higher at the sensor closest to the refiner axis. Higher coefficients of friction were measured in the primary stage refiner, which also showed less active bar-crossings. Distributions of peak force values were generated for a range of standard operating conditions. Primary stage refining showed near decreasing exponential distributions, while rejects refining showed skewed normal distributions. These results indicate a fundamental difference in the behavior of these refiners, which is explained in terms of the processing stage of the wood fibre and scale of the refiner. Past laboratory experiments in a single-bar refiner have shown that pulp consistency can greatly affect the contact mechanics of bar-crossing impacts. The effect was observed as a positive correlation between the coefficient of friction and the mass fraction of fibre in the stock, known as the consistency. In the present work, a similar correlation was found in the primary stage refiner, but only in the sensor closest to the refiner axis. No significant changes in the coefficient of friction were observed in the rejects refiner; however, only a small range of consistencies was tested. These initial findings suggest relationships found in past laboratory tests may translate to larger-scale equipment. The clashing of plates during refining accelerates bar wear, and delays production. An investigation of the ability of the sensor to predict plate clash was conducted. The force sensors consistently provided advanced warning of a clash event, many seconds before the accelerometer-based plate protection system currently in use by the mill. A sensitivity study showed that the new system was able to outperform the accelerometer system over a range of detection settings, and that the accelerometer could not be tuned to match the performance of the new system.

No description available.

The Accelerated Mortar Bar test (AMBT) is rapid, reproducible, and perhaps the most widely used technique for examining the potential alkali-silica reactivity of aggregates. Unfortunately, this test is often unreliable as it may identify non-reactive aggregate as reactive and vice versa. With the aim of improving the accuracy of AMBT, two modifications to the current procedure were evaluated: 1) the maturity of mortar bars prior to alkali hydroxide exposure and 2) reduction of the storage temperature. The original and modified versions were performed on six aggregates with alkali-silica reactive (ASR) components, and their expansions and ASR classifications were compared. Results show that increasing the maturity had no significant impact on expansions. However, modifying the storage temperature to 60˚C and extending the period of testing to 28 days can be very effective in terms of more reliably identifying the existing falsely identified aggregates.

The Accelerated Mortar Bar test (AMBT) is rapid, reproducible, and perhaps the most widely used technique for examining the potential alkali-silica reactivity of aggregates. Unfortunately, this test is often unreliable as it may identify non-reactive aggregate as reactive and vice versa. With the aim of improving the accuracy of AMBT, two modifications to the current procedure were evaluated: 1) the maturity of mortar bars prior to alkali hydroxide exposure and 2) reduction of the storage temperature. The original and modified versions were performed on six aggregates with alkali-silica reactive (ASR) components, and their expansions and ASR classifications were compared. Results show that increasing the maturity had no significant impact on expansions. However, modifying the storage temperature to 60˚C and extending the period of testing to 28 days can be very effective in terms of more reliably identifying the existing falsely identified aggregates.

The aim of this study is to present a design approach for compliant bistable four-link mechanisms. The design constraints are the two positions of the mechanism, the force required to snap between the positions and the fatigue life of the designed mechanism. The theory presented here will be applied to the door lock mechanism used in commercial dishwashers, which is originally designed as a rigid inverted slider crank mechanism snapping between two positions with the force applied by a spring. The mechanism is re-designed as a compliant bistable four-link mechanism and a prototype has been manufactured.

Freiburg i. Br., Univ., Studienarb., 2005.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.