The goal of this thesis is to develop a novel polishing tool system, which can be attached to a CNC machine tool and execute a precision polishing job for an axially symmetric free surface. The precision polishing job is to remove the error surface profile, left by the previous machining process, on the work to improve its form precision. The system mainly includes a mechanism of 3 degrees of freedom, a misalignment compensator mounted on the mechanism, and an oscillation-free connector between tool and driver. The mechanism was designed to meet the required motions of tool trajectories. These motions are to assure the tool can play three specific functions. The first one is to keep the tool axis maintain a constant angle with the normal of polished surface. The second one is to control the wear rate distribution of tool to reduce the effect of tool wear on polishing rate. The final one is to achieve the goal of uniform polishing quality at every spot of polished surface. The conceptual design of this mechanism is done based on a strategy of problem decomposition. The misalignment compensator is to reduce the effect of tool misalignment on the variation of polishing rate. The compensator allows a translational motion and is constrained by a spring. When the tool is mounted on the compensator, the study will show that with a proper spring constant the effect of tool misalignment can be significantly reduced. The study will indicate that the smaller the tool mass is the higher the compensation efficiency can be. The oscillation-free connector is to separate the tool and its driver so that the mass of driver is not included in tool, while the driving function retains. It is composed of two parts. One part is connected to tool and the other one is mounted on driver. These two parts are not joined together by any mean. However, the motions of two parts will interfere with each other. Thus, the driving function between tool and drive can be maintained. It is noted that the vibration of driver can be successfully isolated from the tool if a soft material is attached to one part.

Precast concrete sandwich wall panels (PCSWPs) have been used in the precast industry for decades due to their durability, rapid construction, and thermal efficiency. Shear connectors are used to connect the two wythes of concrete to allow composite action of the system. The use of glass fiber reinforced polymer (GFRP) connectors is a relatively recent breakthrough in PCSWP design. GFRP connectors allow full composite action to occur, while still maintaining the thermal efficiency of the system by not allowing thermal bridging to occur. In order to design concrete sandwich panel systems to act compositely, the engineer must obtain design values from a connector manufacturer, often times making engineers uncomfortable. Shear connectors are typically proprietary and are required to first have design values often times varies by each company. This project aimed to compare existing testing methodologies in order to better inform engineers about design decisions. This project used two methodologies of shear testing on five different types of composite action connectors. Testing was performed using single-shear and double-shear "push-off" tests. In order to gather enough statistical data to compare the testing methodologies, 22 single-shear and 48 double-shear small scale specimens were designed, fabricated, and loaded through failure at the Utah State University SMASH Lab. Testing was performed by applying loads perpendicular to the connectors and measuring the load and amount of deflection that occurred. Using the load-deflection relationships obtained, stiffness values were calculated and recorded for each test. A statistical analysis was performed based on the observed data. This study concluded that the ultimate strength capacity and stiffness of connectors will change depending on the testing methodology used. Single-shear testing will generally provide less ultimate strength and less stiffness when compared to double-shear testing.

This report describes the development of a high-voltage connector at the request of Scandinova Systems AB in Uppsala. The development process is described from the making of a customer demand specification, to the making of drawings for the manufacturing of prototypes. Scandinova develops high-voltage modulators, hence the need for connectors that can handle very large power pulses. Their current connector has several weaknesses that may cause the connector to melt or catch fire. The development began with a number of studies that included the modulator structure and the current connector structure and functions. In addition, to collect Further demands, requests or ideas for the new product a survey were distributed to the staff at Scandinova. All the collected information was summarized in a a customer demand specification. There after a wide variety of concepts were generated. The concepts were then compared, merged, improved, or rejected in order to get a stronger concept. The remaining concepts were then evaluated using a concept selection matrix. In consultation with Scandinovas R & D department it was then decided to further develop four of the concepts in 3D CAD. The selected concepts was then designed in detail and the material selection were made. This was followed by a final evaluation with Scandinova to evaluate the concepts. The evaluation showed that three of the concepts were still interesting. Therefore, drawings were produced for the remaining three concepts, the drawings were there after submitted to Scandinova for prototyping. This report shows that at least one of the concepts seems to be substantially better than Scandinovas current high-voltage connector.

The effects of different ferrule length and epoxy layer thickness of the module of optical fiber connector under thermal cycling are investigated in this thesis. The finite element method package, MSC. MARC, is used in this study and the coupled thermal-elastic-plastic model is employed in the analysis. The mechanical behavior and life prediction with different length of ferrule and thickness of epoxy layer are considered. It is shown that the thickness of epoxy layer has the major effect on the life of the module. The stress and strain in the fiber and epoxy layer are decreasing with increasing of ferrule length, and the life of the module is increasing with increasing of thickness of epoxy layer. Finally, we recommend the ferrule length can be designed between 7.89mm ~10.5mm.

No description available.

This paper presents the development of a finite element method for modeling fastener joints in aircraft structures. By using connector element in commercial software Abaqus, the finite element method can handle multi-bolt joints and secondary bending. The plates in the joints are modeled with shell elements or solid elements. First, a pre-study with linear elastic analyses is performed. The study is focused on the influence of using different connector element stiffness predicted by semi-empirical flexibility equations from the aircraft industry. The influence of using a surface coupling tool is also investigated, and proved to work well for solid models and not so well for shell models, according to a comparison with a benchmark model. Second, also in the pre-study, an elasto-plastic analysis and a damage analysis are performed. The elasto-plastic analysis is compared to experiment, but the damage analysis is not compared to any experiment. The damage analysis is only performed to gain more knowledge of the method of modeling finite element damage behavior. Finally, the best working FE method developed in the pre-study is used in an analysis of an I-beam with multi-bolt structure and compared to experiments to prove the abilities with the method. One global and one local model of the I-beam structure are used in the analysis, and with the advantage that force-displacement characteristic are taken from the experiment of the local model and assigned as a constitutive behavior to connector elements in the analysis of the global model.

The design and study of multiple RF direct digital manufactured (DDM) devices are presented in this work. A 2.45 GHz, 180°; hybrid coupler is designed to provide the space required for other system components. The coupler is designed and manufactured on a 32 mil Rogers 4003C substrate and adapted to a 100% in-fill acrylonitrile butadiene styrene (ABS) substrate. A size reduction of 66% is accomplished with a bandwidth of 16%. A DDM Ku band connector is modeled and fabricated using varying relative dielectric constants of 50% and 100% in-fill ABS. The connector maintains less than 0.45 dB of insertion loss up to 14 GHz and greater than 10dB of return loss up to 15 GHz. A lumped component model is also developed to model the damaged transition of the connector with agreement to numerical electromagnetic simulation software. Lastly, a thermal and RF study of a Ku band power amplifier (PA) is performed. Two 5 mil 100% in-fill ABS PA test fixtures are fabricated with a varying number of vias. The designs are biased at various operating points to collect thermal and RF data. The PA operates at 151°C before melting the ABS substrate. A thermal model is developed from the measurement data to predict the temperatures at given power levels with good agreement between simulation and model data.

Electrical connectors are widely utilized for signal communications in automotive electronic systems whose performance is related to the reliability of the entire system. Electrical connectors are frequently affected by the engine vibration, resulting in fretting damages on electrical connector. In this thesis, the main propose is to find a signal analysis method to predict the fretting damages on fuel pump connector induced by engine vibration. The data of the fuel pump connector is studied from a vibration test of the four-cylinder engine and the dominating frequencies are used in the fretting test to verify the analysis method. The fretting damage is identified through visual inspection by microscope. The model of the connector is built in COMSOL to explain the fretting on the contact surfaces. The results present the signal analysis method can be directly used to predict the risk of fretting damages during the engine vibration. Some significant frequencies are pointed out as guidelines for future tests and optimization.

Due to increasing weight of electrical component and wiring harnesses in a vehicle contrary to the demand of light constructed vehicles as well as the constantly increasing and fluctuating price of copper compared to aluminium’s stable and far lower price, the use of aluminium conductors as an alternative have been promoted.  This thesis work lay theoretical research of the available methods used for electrical connection of aluminium conductors in order to increase the knowledge about the available termination techniques.  Due to aluminium’s characteristics such as lower conductivity and strength, tendency to form oxides and relax over time, differences in thermal expansion coefficient and high potential for galvanic corrosion, there is a risk of deterioration and degradation of the connection if the termination of aluminium conductors is not done correctly without being aware of the challenges when it comes to aluminium connection.  The founded solutions are different welding and soldering techniques such as friction welding, ultrasonic welding, resistance welding, plasma soldering and many other modifications of conventional crimp.  A robust termination system that faces all those challenges and ensure a reliable connection during the entire life length of the vehicle and in order to inhibit corrosion different type of sealing of the contact interface will be required.  In order to evaluate the performance of the founded connection method, testing with evaluation of, tensile strength of conductor to contact attachment, tightness demand, corrosion resistance, vibration and heat evolution at the contact attachment have to be conducted.

Yes / Steel concrete composite beams have been increasingly used in practice due to their advantages with respect to their structural features and constructability. However, in conventional composite beam systems composite action is applied via shear connectors welded at the top flange of the down-stand steel beam and embedded in the concrete slabs, making it less favourable for the beam system to be disassembled and reused. This paper presents a numerical study of a new composite beam system consisting of a cellular steel beam, metal deck flooring and demountable shear connectors. According to the experimental study, this composite beam system made the demounting, reassembly, and member reuse possible, and did not compromise the loading capacity. In the numerical study presented in the paper, a finite element model was developed and validated against the results obtained from the previous experimental study. The parametric study further examined the effects of concrete strength, shear connector arrangements and asymmetry ratios of steel beam section to the load capacity of the composite beam system. The analysis and comparison provided a deeper insight into the behaviour of this type of shear connector. Through this numerical study, the structural merits of the composite beam system using demountable shear connectors were highlighted. Finally, the mid-span plastic moment of the composite beam was predicted using the direction method provided in SCI publications and compared with the moment–deflection relationship obtained from FE modelling. / The research leading to these results is part of a joint project of the University of Bradford, the University of Luxemburg, the Technology University of Delft, the Steel Construction Institute, Tata Steel, Lindab S. A., BmS and AEC3 Ltd. The authors gratefully acknowledge the funding received from the European Commission: Research Fund for Coal and Steel (RFCS-2015, RPJ, 710040). In addition, deep appreciation to Mr. Stephen Robinson for his work done in the laboratory.