Applying engineering principles to tessellation origami-based designs enables the control of certain design properties, such as flexibility, bending stiffness, mechanical advantage, shape conformance, and deployment motion. The ability to control these and other properties will enable augmented design capabilities in environments which currently limit the design to specific materials, including space, medicine, harsh environments, and scaled environments (such as MEMS applications). Other applications will be able to achieve more complex motions or better satisfy design and performance requirements.This research demonstrates augmented design capabilities of origami tessellations in engineering design in rigid-foldable and non-rigid-foldable applications. First, a method to determine Poisson's ratio and mechanical advantage for deployable, rigid-foldable tessellations is presented. The results enable the selection and tailoring of patterns based on deployment motion of specific patterns.Secondly, a model that predicts the deployment stability of the non-rigid-foldable triangulated cylinder is presented. This model defines the geometry needed to obtain a maximum deployed height, always return to a closed position, or remain in either the open or closed configurations. The Stability Transition Ratio is the ratio of the inner to outer diameter that marks the point between monostable and bistable behavior in a triangulated cylinder and is dependent only on the number of sides.Lastly, this work presents methods to reduce sag in adult diapers by increasing shape conformance, promoting wicking capabilities, and improving the structure through the implementation of origami tessellations. Several basic fold patterns were evaluated and the results reported. Reducing sag increases comfort and decreases leaking.

This thesis deals with modification of an existing four-cylinder diesel engine to a singlecylinder research engine. The work is divided into four main parts. The first part is theoretical, briefly describes research engines, their individual types and provides an overview of their functions. The second part of the work includes the modification of a four-cylinder diesel engine to a single-cylinder research engine, focusing mainly on balancing inertia forces. The third, most extensive chapter contains the structural analysis of the crankshaft. The last part contains the design of a torsional coupling, which ensures the connection of the engine with the dynamometer.

The topic of this diploma thesis was chosen by Valeo Compressor Europe Company. The aim is to propose an automation of the production line for grinding of a compressor part. The part is internally termed “Cylinder,” and it is an integral part of a new type of a rotational compressor for air-conditioning units of automobiles. The diploma thesis includes a complete proposal for the automation of workplace. The current state, the proposal of the concept, technical specification of the project, and the choice of a suitable supplier and economical assessment are included. The data were provided by Valeo Compressor Europe Company.

Over the past 25 years, advances in the field of turbulence modeling have been made in an effort to resolve more scales, preserving unsteadiness within a flow. In this research two hybrid models, Scale-Adaptive Simulation (SAS) and Stress-Blended Eddy Simulation (SBES) are implemented in solving the highly unsteady flow over a rotating arrangement of three cylinders. Results are compared to those from wind tunnel experiments carried out at North Dakota State University. Both models show close agreement with first and second order turbulence quantities, and SBES shows much greater flow structure detail due to its ability to resolve smaller scales. The Strouhal number for the flow is found to be a function of the rotational speed of the arrangement with von Karman-like structures resulting from each cylinder's wake over a full rotation. SAS shows a constant computational cost as Re increases while the SBES's computational cost increases relatively linearly.

Student Number : 9202983Y - PhD thesis - School of Computational and Applied Mathematics - Faculty of Science / A derivation is given of the constitutive equation for an incompressible transversely isotropic hyperelastic material in which the direction of the anisotropic director is unspecified. The field equations for a transversely isotropic incompressible hyperelastic material are obtained. Nonlinear radial oscillations in transversely isotropic incompressible cylindrical tubes are investigated. A second order nonlinear ordinary differential equation, expressed in terms of the strain-energy function, is derived. It has the same form as for radial oscillations in an isotropic tube. A generalised Mooney-Rivlin strainenergy function is used. Radial oscillations with a time dependent net applied surface pressure are first considered. For a radial transversely isotropic thin-walled tube the differential equation has a Lie point symmetry for a special form of the strain-energy function and a special time dependent applied surface pressure. The Lie point symmetry is used to transform the equation to an autonomous differential equation which is reduced to an Abel equation of the second kind. A similar analysis is done for radial oscillations in a tangential transversely isotropic tube but computer graphs show that the solution is unstable. Radial oscillations in a longitudinal transversely isotropic tube and an isotropic tube are the same. The Ermakov-Pinney equation is derived. Radial oscillations in thick-walled and thin-walled cylindrical tubes with the Heaviside step loading boundary condition are next investigated. For radial, tangential and longitudinal transversely isotropic tubes a first integral is derived and effective potentials are defined. Using the effective potentials, conditions for bounded oscillations and the end points of the oscillations are obtained. Upper and lower bounds on the period are derived. Anisotropy reduces the amplitude of the oscillation making the tube stiffer and reduces the period. Thirdly, free radial oscillations in a thin-walled cylindrical tube are investigated. Knowles(1960) has shown that for free radial oscillations in an isotropic tube, ab = 1 where a and b are the minimum and maximum values of the radial coordinate. It is shown that if the initial velocity v0 vanishes or if v0 6= 1 but second order terms in the anisotropy are neglected then for free radial oscillations, ab > 1 in a radial transversely isotropic tube and ab < 1 in a tangential transversely isotropic tube. Radial oscillations in transversely isotropic incompressible spherical shells are investigated. Only radial transversely isotropic shells are considered because it is found that the Cauchy stress tensor is not bounded everywhere in tangential and longitudinal transversely isotropic shells. For a thin-walled radial transversely isotropic spherical shell with generalised Mooney-Rivlin strain-energy function the differential equation for radial oscillations has no Lie point symmetries if the net applied surface pressure is time dependent. The inflation of a thin-walled radial transversely isotropic spherical shell of generalised Mooney-Rivlin material is considered. It is assumed that the inflation proceeds sufficiently slowly that the inertia term in the equation for radial oscillations can be neglected. The conditions for snap buckling to occur, in which the pressure decreases before steadily increasing again, are investigated. The maximum value of the parameter for snap buckling to occur is increased by the anisotropy.

Scania uses powder plasma spray technology to coat their cylinder linings. The powder used contains stainless steel and ceramics. In order for the properties of the coating to reach the quality demands, it has to have a certain amount of pores and ceramics in it. Despite the process being strictly controlled the coating has proven to exhibit differences in composition. Process parameters for each coated lining are logged and as part of Scania’s quality control, samples of the coating are frequently tested. For the purpose of this work, three process parameters were mapped in search for correlations to the composition of the coating – electric current, voltage and power output. To investigate the homogeneity of the powder it was analyzed using Scanning Electron Microscopy. The main findings were that there are no correlations found between the three process parameters and the composition of the coating. Moreover, in the powder analysis it was found that the composition of the powder itself varies to an extent that elements differ as much as twice the amount in between different batches and sites in the production. The results imply that it is difficult to prevent irregularities by managing process parameters. The variations in powder composition need to be further investigated in order to determine its impact on the quality of the coating.

Tandem cylinder flow control in the form of dielectric barrier discharge, DBD, plasma actuation on the upstream cylinder is used to control the wake and flow around the downstream cylinder. Twin spanwise-oriented plasma actuators are mounted at ± 80 degrees from the forward stagnation point of the upstream cylinder. The actuators are powered with two different AC voltage levels, low-power forcing and high-power forcing. Flow control experiments are performed at Reynolds number 4,700, and cylinder spacing range 3 > L/D > 5. Results include pressure measurements on the downstream cylinder and wake surveys using Particle Image Velocimetry, PIV. High-power forcing reduces the height between vorticity peaks behind upstream cylinder and, in the case of L=3D, restricts upstream wake from impinging on downstream cylinder.

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