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In this thesis a Power-Hardware-in-the-Loop (PHiL) test rig is developed forhydro-pneumatic suspension by utilizing the physical suspension unit together with asimulated vehicle model in MATLAB Simulink. Power-Hardware-in-the-Loop is the termfor combining simulation models with power-transmitting hardware components inreal-time. This is useful when a system contains some parts that are complex and somethat are simpler to model. The simple parts of the system can be modelled andsimulated in conjunction with more complex parts consisting of physical objects. Thereason for keeping the items to be tested as physical components is their complexity andunknown characteristics that can be difficult to estimate. By utilizing PHiL, vehiclecomponents can be tested and developed without the need for the actual vehicle, whilekeeping the characteristics that the physical vehicle would bring. The process included development of a real-time enabled vehicle model, evaluation ofcontrol strategies as well as selection of hardware used for a small scale test rig. The project resulted in a functional small scale single wheel test rig. Validationexperiments confirmed that the rig produced results close to expectations. Thecommunication between the the test rig and the simulated model was accurate andshowed the potential for a full scale test rig. It can be concluded that a PHiL test rigcan be a suitable option to full vehicle testing. The vehicle model is fully customisable,so that the suspension units can be tested in various configurations of vehicles.

Denna rapport avser det examensarbete som har utförts i samarbete med AB Volvo Penta under vårterminen 2022. Arbetet beskriver produktutvecklingsprocessen för en lamellprovrigg.Volvo Penta i Köping utvecklar och tillverkar transmissioner för marint bruk. De har problem att få noggranna mätningar av effektförluster i lamellpaketen som sitter i transmissionen. Därför önskar Volvo Penta en lamellprovrigg för att kunna mäta effektförlusterna i ett frånkopplat lamellpaket. Projektet avgränsas till att endast ta fram en layoutkonstruktion med val av huvudkomponenter och funktionsbeskrivning för lamellprovriggen.Innan produktutvecklingsprocessen påbörjades gjordes en förstudie för att granska befintliga lamellprovriggar. Förstudien konkluderas med att dagens lamellprovriggar inte kan utföra tester under de driftförhållanden som önskas i den provrigg som examensarbetet avser konstruera, därför kan endast huvudkomponenter i tidigare lamellprovriggar granskas och inte hela provriggskoncepten. Genom konceptgenerering och -utvärdering tas en layoutkonstruktion fram och huvudkomponenter specificeras. Motrotation på lamellpaket skapas med Duoprop-system. Förlustmätningar av moment samt värmeutveckling utförs. Mätning av både moment och varvtal görs med ett momentnav som är placerad vid motorn för att mäta det som förs in i systemet. Temperatur och flöde mäts på flera ställen i hydraulsystemet för att kunna variera det önskade driftförhållandet.Resultatet är underlag till en provrigg som efterliknar Volvo Pentas IPS-transmissions driftförhållanden och ger möjlighet till provning av nya material, oljor och dimensioner. Konstruktionens avsikt är att ge underlag på en layout av en lamellprovrigg som lämpar sig till Volvo Pentas fysiska och teoretiska behov. Konstruktionen är genomarbetad och bör vara en stabil byggsten för kommande arbete fram till tillverkning och montering. / This report refers to the bachelor’s thesis that has been carried out in collaboration with AB Volvo Penta during the spring term 2022. The work describes the product development process for a wet disc clutch test rig.Volvo Penta in Köping develops and manufactures transmissions for marine applications. Their problem is getting accurate measurements of power losses in the wet clutch packages contained in the transmission. Volvo Penta therefore have the desire for a wet disc clutch test rig to be able to measure the power losses in a disconnected friction disc package. The project is limited to developing only a layout design with a selection of main components and a functional description for the wet disc clutch test rig.Before the product development process began, a feasibility study was conducted to examine existing friction disc test rigs. The feasibility study concludes that today's test rigs can not perform tests under the desired operating conditions in the test rig that the degree project intends to construct, therefore only main components in previous test rigs can be examined and not the entire test rig concept. Through concept generation and evaluation, a layout construction is developed and the main components to it are specified. Counter-rotation on friction disc packages is created with a Duoprop-system. Loss measurements are performed for torque and heat generation. Measurements for both torque and rotational speed are done with a torque sensor that is located at the engine to measure what is fed into the system. Temperature and flow are measured in several places throughout the hydraulic system in order to be able to vary the desired operating conditions.The result is the basis for a wet disc clutch test rig that mimics Volvo Penta's IPS transmission’s operating conditions and provides an opportunity to test new materials, oils and dimensions. The purpose of the design is to provide a basis for a layout of a wet disc clutch test rig that suits Volvo Penta's physical and theoretical needs. The construction has been thoroughly evaluated and should be a stable building block for future work until manufacturing and assembly.

In today’s society, there is a growing emphasis on renewable energy generation to reduce greenhouse gas emissions, particularly carbon dioxide (CO2) and methane(CH4). Among renewable sources, wind power has emerged as one of the most rapidly advancing technologies, with floating offshore wind turbines showing significant potential due to their ability to be installed in deeper waters. This study investigates the feasibility of implementing a LFA machine The abbreviation"LFA" used in this report for the machine comes from swedish "Luftgapslindadflerpolig asynkronmaskin" (meaning "Airgap armature winding Multipole Asynchnousmachine") in a Counter Rotating Axis Floating Turbine (CRAFT) system, developed by Hans Bernhoff and the Norwegian company WorldWideWind. The CRAFT system consists of two three-bladed turbines rotating in opposite directions, linked to a rotor and stator respectively, to maximize potential energy extraction by doubling the angular velocity. The LFA aims to optimize the potential between the turbines by regulating the speed of one of the axes. This report specifically examines the torque curve of the LFA when it operates as a motor at various speeds. Experimental setups included coupling the LFA motor with a known generator(TGET550-5KW-300R) and measuring the motor’s performance. The data collected allowed for an analysis of the torque and efficiency of the LFA. Despite initial challenges with power limitations from the drive unit, iterative tests and calculations provided insights into the LFA’s inertia and torque characteristics. The study concludes with an evaluation of the LFA’s suitability for enhancing the efficiency of the CRAFT system in floating offshore wind applications. The study concludes with an evaluation of the LFA’s suitability for enhancing the efficiency of the CRAFT system in floating offshore wind applications.

Sound generation and propagation in circular ducts for frequencies beyond the cut-on frequencies of several higher order acoustic modes is investigated. To achieve this, experimental and numerical set-ups are designed and used to research aeroacoustic interactions between in-duct components and to conceive noise mitigation strategies. Describing in-duct sound for frequencies with a moderate number of propagating modes is important, for example, for improving the noise emission from mid-size ventilation systems. Challenges that are largely unacknowledged in the literature involve efficient test rig design, quantification of limits in the methods, numerical modelling, and development of effective noise mitigation strategies for higher order modes. In this thesis, in-duct sound is mapped on a set of propagating pressure eigenmodes to describe aeroacoustic components as multi-ports with sound scattering (passive properties) and a source strength (active properties). The presented analysis includes genetic algorithms and Monte Carlo Methods for test rig enhancement and evaluation, multi-port network predictions to identify model limitations, and scale resolving (IDDES) and Linearized Navier Stokes computations for numerical multi-port eduction and the silencer design. It is first shown that test rig optimization improves the quality of multi-port data significantly. Subsequently, measurements on orifice plates are used to test the network prediction model. The model works with high accuracy for two components that are sufficiently separated. For small separations, strong coupling effects are observed for the source strength but not for the scattering of sound. The measurements are used for numerical validation, which gives reliable results for coupled and uncoupled systems. The total acoustic power of tandem orifices is predicted with less than 2 dB deviation and the passive properties for most frequencies with less than 5 % difference from the measurement. The numerical (FEM) models are also used to design a completely integrated silencer for spinning modes that is based on micro-perforated plates and gives broadband attenuation of 3-6 dB per duct diameter silencer length. The multi-port method is a powerful tool when describing aerodynamically decoupled in-duct components in the low- to mid-frequency range. Due to a robust passive network prediction, multi-port methods are particular interesting for the design of silencer stages. Furthermore, the demonstrated applicability to numerical data opens novel application areas. / <p>QC 20170522</p> / IdealVent

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Automotive transmission rattle is the noise generated due to impacts between manual transmissions meshing gear teeth in the presence of backlash. It is considered to be a Noise, Vibration and Harshness (NVH) phenomenon and is originated due to combustion irregularities (engine order vibrations), especially in diesel vehicles. This thesis focuses in the case of creep rattle for the MMT6 Ford Getrag transmission (six speeds plus reverse) with a DW10b, 4-cylinder, 4-stroke, 2.0 litres diesel engine. This particular rattle condition is fundamentally similar to any other where an engaged gear is pertained (drive, over-run or float), with the 1st or 2nd gear engaged at a very low engine speed. The numerical models include an initial single degree of freedom (DoF) simulation. It comprises either of the engaged gear pair under Hertzian contact conditions or of a loose gear pair under hydrodynamic regime of lubrication. Once the validity of this model is established and correlated with the results obtained from a single gear pair test rig, simulations of increasing complexity can be envisaged. A 7 DoF numerical model is, therefore, developed. The Hertzian contact model still prevails for the engaged gear pair, whereas an analytical hydrodynamic solution is implemented for the remaining 6 loose gear wheels and Petrov s law is applied to the needle bearings retaining the gear wheels. With the aim of accommodating a fully lubricated model of all the tribological conjunctions, an analytical elastohydrodynamic (EHL) Grubin type algorithm is employed. Also, the energy equation is analytically solved for hydrodynamic and elastohydrodynamic conjunctions, based on the assumptions dictated by the Peclet number. Therefore, under hydrodynamic conditions, the energy equation is governed by viscous heating and convective cooling, whereas in the EHL conjunctions the governing terms are viscous and compressive heating, together with conductive cooling. The retaining needle bearings follow the same heat generation mechanism as journal bearings. The effective viscosity, as obtained from the Houpert s equation accounting for pressure and thermal effects, is fundamental for the study of the friction in the contact. The hydrodynamic contacts are only governed by viscous friction, whereas EHL conjunctions exhibit asperity iv interactions as well as viscous effects. The results obtained from this new 7 DoF model are then compared to the experimental measurements taken from the vehicle tests and various purpose-built drivetrain rigs. A metric named Impulsion Ratio is hereby introduced, aiming to shed some light into the predictions obtained by the various models presented. This metric is the ratio of driving over resistive forces acting on each individual gear wheel. Its use is tested to predict single or double-sided rattle scenarios and, therefore, ascertaining higher and lower rattle levels. The 13 DoF model from which these conclusions were obtained includes shafts planar translation and rocking moments. The rolling element bearings supporting the shafts are, therefore, modelled to capture the inherent frequencies arising from their motion. The final model introduces the effects of transient thermo-elastohydrodynamics. This 7 DoF dynamic model accounts for a numerical solution of Reynolds equation with Elrod s cavitation algorithm for simultaneous teeth in mesh. The results obtained validate the previously used Grubin assumption by comparing the predicted central film thickness along the full mesh of one tooth. Also, the effect of starved input conditions and thermal and isothermal solutions are studied.

Road vehicle tyres, railway wheels and ball bearings all generate rolling contact forces which are transferred within a finite area of contact between the rolling element and the substrate. Either it is visible or not for the human eye, a certain degree of roughness is always present on the contacting surfaces and it influences the generation of both vertical and lateral contactforces. The purpose of this investigation is to enhance the understanding and modelling of the influence from small-scale surface roughness on the generation of rolling contact forces. To this end, a computationally efficient method to include roughness-induced contact nonlinearities in the dynamic modelling of rolling contacts is proposed. The method is implemented in a time domain model for vertical wheel–track interaction to model rolling-induced rail vibrations, showing good agreement with measurements. Furthermore, a test rig is developed and used for the investigation of tyre–road rolling contact forces. Detailed studies are performed on the influence of substrate roughness on the resulting contact forces for a tyre tread block which is rolling at different operating conditions. The choice of substrate as well as the rolling velocity and the slip ratio is observed to have significant influence on the resulting friction coefficient. For high slip ratios, stick–slip oscillations appear, exhibiting frequency content which is largely dependent on the choice of substrate. The outcomes of this study can potentially be used to improve future tyre–road contacts with respect to wear, traction and noise generation. / <p>QC 20161013</p> / Centre for Eco2 Vehicle Design

The master’s thesis deals with a design of a radial journal bearing simulator, which is ready to implement a transparent sapphire journal bearing to an optical observation of the oil film. The first part of this thesis contains a short review of a few currently used journal bearing test rigs. The next part of the work deals with a discussion of concept variants and a definition of important parameters. The last part contains a detailed description of the designed radial journal bearing simulator. Limitations of the designed simulator and recommendations for future improvements are also discussed. The result of the presented work is the designed journal bearing simulator which will allow observing of the oil film. The work also consists a complete design documentation.

This master’s thesis is focused on measurement of electrical contact resistance. The beginning of the thesis is devoted to the introduction of the electrical contact resistance and electrical parameters of journal bearings. Next part of the thesis deals with engineering design of test rig. In order to verify functional measurement principle, the test rig based on engineering design has been made. In the end of the thesis the measuring devices and the measuring process is described. The measurement results from the test rig are presented.