This thesis project was conveyed in collaboration with Block Zero, a strategic Design Studio in Malmö, Sweden, with the purpose to design a product that develops a new type of interaction within the Smart Home. This design project will primarily focus on the research, exploration and definition of possible solutions, and the resulting design and development of the final product, a Smart Home Health Hub. From a global perspective, throughout the following document is covered a description of the design process from initial research to the final prototype. The project is defined in this approach and establishes the mentioned principles to guide the execution of the project through a deductive method, synthesising until the final result.

Fiber-reinforced plastics for industrial applications face constantly increasing demands regarding efficiency, reliability, and economy. Furthermore, it was shown that fiber-reinforced plastics with tailored reinforcements are superior to metallic or monolithic materials. However, a trustworthy description of the load-specific failure behavior and damage evolution of composite structures can hardly be given, because these processes are very complex and are still not entirely understood. Among other things, several research groups have shown that material damages like fiber fracture, delamination, matrix cracking, or flaws can be discovered by analyzing the electrical properties of conductive composites, for example, carbon fiber–reinforced plastics. Furthermore, it was shown that this method could be used for structural health monitoring or nondestructive evaluation. Within this study, magnetic induction tomography, which is a new imaging approach, is introduced in the topic of nondestructive evaluation of carbon fiber–reinforced plastics. This non-contacting imaging method gains the inner spatial distribution of conductivity of a specimen and depicts material inhomogeneity, like damages, not only in two-dimensional images but also in three-dimensional images. Numerical and experimental investigations are presented, which give a first impression of the performance of this technique. It is demonstrated that magnetic induction tomography is a promising approach for nondestructive evaluation. Potentially, it can be used for fabrication quality control of conductive fiber–reinforced plastics and as a structural health monitoring system using an integrated or superficially applied magnetic induction tomography setup.

Structural health monitoring (SHM) is damage detection strategy for aerospace, civiland mechanical infrastructure. This project tries to show that Lamb waves, that are being generated and sensed with piezoelectric transducers, can be used for damage detection in a SHM system. For these piezoelectric transducers to work, filtering and amplification circuits needs to be connected to them. This report include the design,simulation, assembly and testing of these circuits. Due to lack of time, it was not possible to generate and sense actual Lamb waves. The result of the thesis is thatsimulations and tests show that it is possible to generate and sense Lamb waves for damage detection in a SHM system / Structural health monitoring (SHM) är en skadedetekteringsstrategi för flyg-,civil- och mekanisk infrastruktur. Detta projekt försöker visa att Lambvågor, som genereras och avkänns med piezoelektriska givare, kan användas för skadedetektering i ett SHM-system. För att dessa piezoelektriska givare ska fungera krävs att filtrerings- och förstärkningskretsar är anslutna till dem. Denna rapport inkluderar design, simulering, montering och testning av dessa kretsar. På grund av tidsbrist var det inte möjligt att generera eller avkänna Lambvågor. Resultatet av examensarbetet är att simuleringar och tester visar att det är möjligt att generera och avkänna Lambvågor för skadedetektering i ett SHM-system.

Spectrally-based fiber optic sensors are a rapidly maturing technology capable of sensing several environmental parameters in environments that are unfitting to electrical sensors. However, the sensor interrogation systems for this type of sensors are not yet fit to replace conventional sensor systems. They lack the speed, compact size, and usability necessary to move into mainstream test and measurement. The Fiber Sensor Integrated Monitor (FSIM) technology leverages rapid optical components and parallel hardware architecture to move these sensors across the research threshold into greater mainstream use. By dramatically increasing speed, shrinking size, and targeting an interface that can be used in large-scale industrial interrogation systems, spectrally-based fiber optic sensors can now find more widespread use in both research labs and industrial applications. The technology developed in this thesis was demonstrated by producing two advanced interrogators: one that was one half the size of commercially available systems, and one that accelerated live spectral capture by one thousand times – both of which were operated by non-developers with little training.

The objective of this thesis is to develop vibration-based fault detection strategies for on-line condition monitoring of gear transmission systems. The study divides the thesis into three sections. First of all, the local stresses created by a root fatigue crack on a pinion spur gear are analyzed using a quasi-static finite element model and non-linear contact mechanics simulation. Backlash between gear teeth which is essential to provide better lubrication on tooth surfaces and to eliminate interference is included as a defect and a necessary part of transmission design. The second section is dedicated to fixed axis power trains. Torsional vibration is shown to cause teeth separation and double-sided impacts in unloaded and lightly loaded gearing drives. The transient and steady-state dynamic loading on teeth within a two stage crank-slider mechanism arising from backlash and geometric manufacturing errors is investigated by utilizing a non-linear multi-body dynamics software model. The multi-body model drastically reduces the computation time required by finite element methods to simulate realistic operation. The gears are considered rigid with elastic contact surfaces defined by a penalty based non-linear contact formulation. The third section examines a practical differential planetary transmission which combines two inputs and one output. Planetary gears with only backlash errors are compared to those containing both backlash and tooth defects under different kinematic and loading conditions. Fast Fourier Transform (FFT) analysis shows the appearance of side band modulations and harmonics of the gear mesh frequency. A joint time-frequency analysis (JTFA) during start-up reveals the unique vibration patterns for fixed axis gear train and differential planetary gear, respectively, when the contact forces increase during acceleration.

This thesis focuses on the simulation of the gyroscopic effect using the software MSC Adams. A simple shaft-disk system was created and parameter of the sys-tem were changed in order to study the influence of the gyroscopic effect. It was shown that an increasing bearing stiffness reduces the precession motion. Fur-thermore, it was shown that the gyroscopic effect vanishes if the disk of system is placed symmetrically on the shaft, which reduces the system to a Jeffcott-Ro-tor. The second objective of this study was to analyze different defects in a simple fixed axis gear set. In particular, a cracked shaft, a cracked pinion and a chipped pinion as well as a healthy gear system were created and tested in Adams. The contact force between the two gears was monitored and the 2D and 3D frequency spectrum, as well as the Wavelet Transform, were plotted in order to compare the individual defects. It was shown that the Wavelet Transform is a powerful tool, capable of identifying a cracked gear with a non-constant speed. The last part of this study included fault detection with statistical methods as well as with the Sideband Energy Ratio (SER). The time domain signal of the individual faults were used to compare the mean, the standard deviation and the root mean square. Furthermore, the noise profile in the frequency spectrum was tracked with statistical methods using the mean and the standard deviation. It was demonstrated that it is possible to identify a cracked gear, as well as a chipped gear, with statistical methods. However, a cracked shaft could not be identified. The results also show that SER was only capable to identify major defects in a gear system such as a chipped tooth.

The interest in structural health monitoring (SHM) has grown considerably in the past half century, due to an explosive growth in the availability of new sensors, the development of powerful data analysis techniques, and the increasing number of civil infrastructure that are approaching or exceeding their initial design life. In SHM, we acquire observation on the behavior of a structure to understand its condition state, based on which we decide how to manage it properly. However, this optimistic view of SHM is in contrast with what happen in real life: infrastructure operators are typically skeptical about the capacity of monitoring to support decisions, and instead of following the suggestions provided by SHM, they often act based on their experience or common sense. The reason is that at present it is not fully clear how in practice to make decisions based on monitoring observation. To fill this gap between theory and practice, I propose to consider SHM as a logical process of making decision based on observation consisting of two steps: judgment, in which the condition state of structures is inferred based on SHM data, and decision, in which the optimal action is identified based on a rational and economic principle. From this perspective, a monitoring system should provide information that can improe he managers knoledge on he srcral condiion sae enough to allow them to make better decision on the structure management. Therefore, in designing a monitoring system, the design target must be the accuracy in the knowledge of structural state achieved analyzing the observations provided by it. However, when an engineer designs a monitoring system, the approach is often heuristic, with performance evaluation based on experience or common sense rather than on quantitative analysis. For this reason, I propose a performance-based monitoring system design, which is a quantitative method for the calculation of the expected performance of a monitoring solution a pre-posteriori and for checking it effectiveness in the design phase. It is based on the calculation of the monitoring capacity and the monitoring demand the counterparts of structural capacity and demand in the semi-probabilistic structural design, and like in structural design, the solution is satisfactory if the capacity is equal or better than the demand. The choice in whether to invest a limited budget on a monitoring system or in a retrofit is another critical choice for infrastructure managers: a retrofit work can increase the capacity and the safety of a structure, while sensors do not change the capacity, nor reduce the loads. Recently, the SHM-community has acknowledged that the benefit of installing a monitoring system can be properly quantified using the concept of Value of Information (VoI). A typical assumption in the VoI estimation is that a single decision-maker is in charge for decisions on both the investment in SHM for a structure, and its management based on SHM data. However, this process is usually more complex in the real world, with more individuals involved in the decision chain. Therefore, I formalize a rational method for quantifying the conditional value of information when two different actors are involved in the decision chain: the manager, who operate the structure based on monitoring data; and the owner, who chooses whether to install the monitoring system or not, before having access to these data. The results are particularly interested, showing that under appropriate conditions, the owner may be willing to pay to prevent the manager to use the monitoring system. Application to case studies are presented for all the research contribution presented in this doctoral thesis.

For creep and shrinkage investigations, relatively small cylindrical specimens are generally exposed to constant climatic conditions. The derived mainly empirical prediction models are used for the calculation of large engineering structures with massive cross-sections. In this paper, the expected values of the material models according to fib Model Code 2010 and Eurocode 2 are compared with monitoring data, which were acquired over a period of more than 12 years during a structural health monitoring of a large viaduct. It was found that in addition to the measured continuous increase in the viscous deformations, seasonal fluctuations due to climatic influences could also be detected. The numerical calculations show that the material models differ significantly in their magnitude and time course of the predicted viscous concrete deformations. In comparison with the monitoring data, a good agreement was achieved when using the material models according to Eurocode 2. The models of the fib Model Code 2010, on the other hand, underestimated the deformations of the massive bridge girder.

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Outlined herein is the Modular Vehicle [MODV] concept as a cost effective, utilitarian, and highly functional vehicle concept for the changing demands placed on a MAGTF [Marine Air-Ground Task Force] or SP-MAGTF [Special Purpose Marine Air-Ground Task Force] in the 21st century. A large focus is put on the importance of modularity and cost effectiveness of having a 24 hour configurable vehicle to a specific mission and area of operation. Off-road vehicle progression through history is presented and successful design features are noted in order to develop underlying goals for the modular vehicle. The thesis emphasizes recent technology advancements that can shift the foundations of vehicle design including wheel hub motors, high capacity batteries, solid oxide fuel cells, autonomy, structural health monitoring, energy harvesting shock absorbers, non-pneumatic tires, and drive-by-wire options. Predictions on the outlook for the technology progressions is discussed to give insight into the viability of basing a vehicle concept on these technologies. Finally, physical design bounds are presented to provide a foundation for the future design of such a vehicle. / Master of Science