Thermal Modelling of a Concept for a Hybrid Micro Combustion Generator

Mobile electronics or remote devices like sensors for the Internet of Things (IoT) require energy storage with increasing energy densities, approaching the limits of the widespread lithium batteries. At the same time, lithium batteries are subject to growing criticism about their environmental impact due to their raw materials and their mining...

Improving the Traction of a Legged Rover: A Biomimetic Approach

Hexapod robots are becoming increasingly popular for navigating and exploring irregular and inhospitable environments. The Lunar Zebro is such a hexapod robot that has been developed to be the lightest and smallest rover to explore the moon. The purpose of the Lunar Zebro is to navigate the surface of the moon where it will encounter difficult...

Redundant Actuation of Twisted and Coiled Polymer Muscles to Improve Tracking Performance

Twisted and coiled polymer muscles (TCPMs) are a type of artificial muscle with a remarkable power-to-weight ratio. However, actuation dynamics are slow compared to other artificial muscles. This work aims to improve dynamic performance by incorporating redundancy. Specifically, this work examines if TCPM bundles of heterogeneous geometries...

Stability Limits of Capillary Aligned Micro-Parts Subject to High Dynamics

Capillary self-alignment shows the potential to keep small components aligned using soft liquid contact when disturbed by external forces. Whilst this concept has been promising, mostly static situations have been investigated, making it unclear how a receptor-droplet-chip (RDC) configuration behaves dynamically and where its stability limits...

A Validation System for the Compressor Side of an Electric Assisted Turbocharger: A study about the validation range of the Compressor map powering the compressor with the electric motor and the Turbin

This study focuses on investigating an alternative validation method to validate the compressor side of turbochargers. Nowadays, the performance of turbochargers is tested using hot gas stands. These hot gas stands are expensive. The application of an externally coupled e-motor to the turbocharger eliminates the need for a hot gas burner -...

On the stiffness of linear roller bearings: On the stiffness of linear roller bearings

This thesis creates and validate a model for predicting the static stiffness of a linear crossed roller bearing as a function of its key design variables within a range of 20%. Linear crossed roller bearings play an essential role in the high-tech industry, this kind of bearing is used for precision applications such as microscopes, optical...

Large-scale overlay: a study into accuracies in roll-to-plate nanoimprint lithography

Roll-to-Plate (R2P) nanoimprint lithography (NIL) is a fabrication process with the potential for low-cost high-volume fabrication of micro- and nano-patterns on large areas. As a result, R2P is regarded as a promising production process for micro- and nano-scale features which exceed the conventional wafer sizes. In addition, the process has...

A Discontinuity-enriched Finite Element Method for Dynamic Fracture in Brittle Materials

The computational modeling of crack propagation is important in aerospace and automotive industries because cracks play a significant role in structural failure. In comparison with the quasi-static case, inertial effects are significant in dynamic crack propagation. The classical numerical tool for modeling dynamic crack propagation is the...

Design of travel limits for bistable vibration energy harvesting

Energy harvesting from renewable energy sources has become more popular in the last decades than ever before. New energy sources consisting of human input vibrations are hopeful alternatives for powering wearable low power electronics. These sensors currently rely on the lifetime of the battery and come along with high maintenance costs in case...

Topology Optimization for 4D-Printed Structures

In recent developments in the field of multi-material additive manufacturing, differences in material properties are exploited to create printed shape memory structures, which are referred to as 4D-printed structures. New printing techniques allow for the introduction of prestresses in the specimen during manufacturing. This research focuses on...

Stiffness compensation for piezoelectric energy harvesting: Improving the efficiency at low-frequency vibrations

In the field of vibration energy harvesting, vibration energy is tranduced to electrical energy to power small, low powered devices. Many energy harvesters are produced in the form of a resonator, where resonant amplification enables efficient operation of the energy harvester. At low frequencies below 10 hz, input motions quickly increase for a...

Manipulating post-buckled compliant mechanisms: Buckling mode interaction as a novel method of stiffness compensation

Bistable vibration energy harvesters are an interesting alternative to their linear counterparts. They allow for large amplitude oscillations between their stable equilibria, from which much energy can be generated. However, the stable equilibria are separated by a potential energy barrier that has to be overcome. Therefore, we cannot guarantee...

Controlling the deposition resolution of nanoparticle aerosols using aerodynamic focusing

The demand for nanoparticles in various applications is increasing. These applications can only be realised if nanoparticles can be specifically arranged and patterned on a substrate. This thesis considers a direct write method that uses an aerodynamic focusing nozzle to deposit these particles. A major challenge arises when the nanoparticles...

Design of a Compliant Hinge based on Closed Form Pressure Balancing

Compliant mechanisms consist of a monolithic body and obtain motion through elastic deformation. Multiple compliant flexure designs are known but their range of motion and load capacity are often limited. When considering rotational hinges, improving the operational range requires reducing the rotation stiffness while increasing normal stiffness...

Towards high-order discontinuity-enriched finite element method

The computational study of discontinuous problems becomes increasingly important due to industrial needs, such as the application of natural or artificial composites and the understanding of damage and fracture processes of materials. The discontinuity-enriched finite element method (DE-FEM) and interface-enriched generalized finite element...

Design of a fluorescent measurementsystem for compliant hydrostaticbearings

A LED induced fluorescent technique based test setup is introduced , which is used to measure the water film thickness of compliant hydrostatic bearings. Fluorescent particles have the characteristic of absorbing light of a certain wavelength and emitting light of a higher wavelength. A LED with a wavelength of 540 nm (green light) is used to...

Air-based Contactless Wafer Precision Positioning System: Contactless Sensing Using Charge Coupled Devices

This thesis presents the development of a contactless sensing system and the dynamic evaluation of an air-bearing based precision wafer positioning system. The contactless positioning stage is a response to the trend seen in the high-tech industry, with the substrates becoming thinner and larger to reduce the cost and increase the yield. With...

Novel Transmission Thermal Model