Дисертації з теми "Test stand design"

Continual development of internal combustion engines requires greater performance from liquid coolants and heat exchangers to maintain optimal temperature. For the purpose of experimental testing of traditional, compact, and microchannel heat exchangers, a test facility has been designed, constructed, and utilized. The facility includes equipment and instrumentation necessary to create operating conditions and record data primarily for testing plate-fin brazed aluminum heat exchanger where heat is being transferred from liquid to air. Other arrangements of heat exchangers could be tested as well with some modifications. Initial tests were performed at several specified operating conditions for three liquids: water, a traditional glycol based Extended Life Coolant (ELC), and a new Glycol Free Coolant (GFC) in an attempt to characterize their heat transfer ability. Results of the tests found that the product of overall heat transfer coefficient and heat exchanger area (UA) was very similar for GFC and water, and it was less for ELC by a narrow margin of 1.3% difference on average. Uncertainty due to instrumentation accuracy was calculated to be 1.8% on average making the results overall UA unverifiable. Measured pressure drop across the heat exchanger which is proportional to required pumping power was found to be 13.5% higher for GFC than ELC at nominal conditions. The GFC offers similar heat transfer performance and marginally increased pumping power requirements compared to the traditional ELC. Due to similar heat transfer performance and the small effect of pressure drop, GFC would be good alternative to ELC due to its less toxic composition.

Within LiU Fluid laboratory there had been a number of hydraulic and pneumatic test stands for research projects and teaching. The effort was needed to do more extension within the field of pneumatics. This thesis was about designing, manufacturing, building and testing the Test Stand for vertical application of pneumatic rodless cylinder. It consisted of three main parts; mechanical structure, pneumatic system and electrical and electronics. The design part focused more on the mechanical structure and pneumatic system. Electrical and electronics had to be installed to facilitate actuation and control of the system after mechanical and pneumatic components were assembled together. The mechanical structure consisted of three main parts; cabinet, carriage and ball balancer. For each part three concepts were generated, evaluated and selected to obtain the most promising concept for further development. The design values were given such that the mechanical structure should have total weight not exceeding 500 kg. The pneumatic system would supply maximum pressure of 8 bar. Upstream pressure was considered to be 6 bar after 25% pressure drop assumed to occur in the system. The mass to be lifted was typically 26 kg moving at a maximum speed of 2 m/s. The whole design process was carried out with safety and design for assembly in mind. The methodologies applied in the design included; identification of need, concept generation, concept selection, CAD modeling and simulation and FE Analysis. Development of concepts involved CAD drawings (3D and 2D) in CATIA V5, calculations and selection of appropriate materials for each component. The pneumatic cylinder applied in this design was a rod-less cylinder (Bosch Rexroth; RTC-DA, MNR: R480628571) with a Piston diameter of 50 mm, stroke of 1.2 m and cushioning stroke of 20 mm. More design information on RTC-DA was not available therefore the information in appendix A was based on series RTC-BV which had close similarities with series RTC-DA. The carriage that moves up and down along the cylinder stroke was designed with a mechanism that imparted disturbance to the system. The mechanism could be set to impart either 100.7 N or 151.02 N disturbance. The design was done with the assumptions that:  Spring force Fs and extension x were constant  The system had sonic flow characteristics and critical flow appeared in meter out orifice.  The air was perfect gas which obeyed equation of state  Specific heat was constant  Viscosity was constant  Flow was one dimensional  System pressure drop was 25% of the maximum supply pressure. Dynamics of the system were estimated analytically and by means of simulation. Corresponding parameter values such as pressure, velocity, flow rate, cushioning stiffness, cushioning force and acceleration were obtained and compared. The product in general conformed to the specifications made prior to the design process.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.
Cataloged from PDF version of thesis.
A test stand was designed and constructed to compress a compliant robot prototype, while measuring the force applied and the displacement of the prototype's end. The prototype is a five degree of freedom, compliant device, which required the design process to preserve these DOF while measuring the force and displacement. To reduce the restriction on the robot's DOF, the final design utilizes a stepper motor and a counterweighted pulley system to apply a compressive force through a single monofilament line. The test stand can accommodate prototypes up to 25 cm in length, and can apply a compressive force up to 6.5N with a resolution of ±0.04N. The displacement can be measured accurately to ±0.064cm.
by Daniel E. Klenk.
S.B.

The aim of this master thesis is to design a test stand for a Hilti Diamond Coring System DD 150-U. The purpose of this stand is to be stable enough to carry out a variety of drilling processes and to allow Institute of Production Engineering and Laser Technology in Technical University in Vienna to conduct different tests and evaluations of the process. The first step is to create a detailed 3D model in SolidWorks 2013. It should eliminate the physical influence of a workers and allow to investigate the drilling process in detail. This means that the drilling operation itself should be conducted without the intervention of human force. In other words the goal is to provide constant force of drilling and easier positioning of the tool according to the location of the hole to be drilled. The design should be suitable for drilling in concrete blocks with size 20x20x20 mm and should assure stable and repeatable operating conditions. As soon as the test stand is created the assembly will be tested with respect to its stifness and stability. This will be done by creating FEM simulations of several critical parts and the whole test stand. The finite elements method (FEM) is a numerical analyses tool that is used for the calculation of the displacements, stresses and strains of those components under internal or external loads such as the force of drilling. These types of simulations are offering the possibility to lower development costs and to save time by eliminating the need of rework and prototypes. In order to provide a constant drilling force weights will be attached to the drilling machine.
Syftet med detta examensarbete är att designa en provbänk för Hilti Diamond Coring System DD 150-U. Provbänken ska vara tillräckligt stabil och flexibel för att man ska kunna utföra olika borroperationer samtidigt som Institute of Production Engineering och Laser Technology på Technical University i Wien ska kunna genomföra olika tester och utvärderingar av processen. Första steget är att skapa en detaljerad 3D-modell i Solidworks 2013. Modellen bör ta hänsyn till arbetstagarens rent fysiska påverkan samt eliminera effekten av denna samtidigt som modellen ska tillåta detaljerad utvärdering av borrproceduren. Detta innebär att borrningen i sig bör kunna genomföras utan mänsklig manuell påverkan. Med andra ord är målet att generera konstant kraft vid borrning och underlätta positioneringen av verktyget i förhållande till platsen där hålet ska borras. Designen utformas så att den lämpar sig för borrning i betongblock med storleken 20x20x20 mm och den bör vara sådan att stabilitet och repeterbarhet säkerställs under normala driftsförhållanden. Så snart provbänken är framtagen kommer den att testas vid montering för att utvärdera provbänkens egenskaper med avseende på styvhet och stabilitet. Detta kommer att ske genom att skapa FEM simuleringar av hela provbänken samt av flera kritiska delar. Finita element metoden (FEM) är ett numeriskt analysverktyg som används för beräkning av förskjutningar, spänningar och töjningar på komponenter vilka uppstår då intern eller extern belastning sker såsom vid borrning. Dessa typer av simuleringar erbjuder möjligheten att sänka utvecklingskostnaderna och spara tid genom att behovet av omarbetningar och prototyper elimineras. För att erhålla en konstant borrkraft kommer vikter att fästas i borrmaskinen.

This Master’s thesis deals with measuring of acting forces from rider to footbike during the ride, followed by the construction of test stand to draw an equivalent load. Measurements and subsequent analysis of acting forces from the rider to the footbike were made. These results were then used for complete design of the test stand. The frame of the test stand was subdued to a stress analysis. A complete automatic control system, including a pneumatic control circuit, was also designed. The proposed automatic test stand was then manufactured and put into operation.

Propõe-se aqui uma metodologia de projeto aero-termo-estrutural de motores foguete a propelente sólido. O projeto de um motor foguete deve ser realizado com o objetivo de cumprir requisitos de uma missão. Para cada veículo espacial, com uma nova missão, um novo motor pode ser projetado, necessitando para isso de uma série de ferramentas robustas, capazes de compreender todas as combinações de esforços existentes no funcionamento de um motor, sob condições de altas pressões e temperaturas. A metodologia aqui proposta é testada e validada em bancada de ensaios desenvolvida para este fim. Os resultados obtidos mostram que a metodologia utilizada se aproxima bastante dos resultados teóricos e pode ser ajustada por coeficientes de eficiência com grande facilidade.
It is proposed here an aero-thermo-structural design methodology for solid propellant rocket motors. The design of a rocket motor must be carried out in order to fulfill requirements of a mission. For each new space vehicle, with a new mission, a new motor can be designed, requiring for it a variety of robust tools, able to comprise all combinations of load existing in the operation of a motor under high pressures and temperatures. The methodology proposed here is tested and validated in bank of tests developed for this purpose. The results show that the methodology is very close to the theoretical results and can be adjusted by coefficients of efficiency with great ease.

The diploma thesis describes the design of a test stand for experimental determination of vibroacoustic parameters of a part of the powertrain system. Thesis contains a research part, describing the problems of the drive system, vibroacoustics, measuring devices and also the division and the description of test stands. At the same time, the reasons for choosing a closed loop test stand are explained. Thesis also includes the results of analytical calculations and numerical results of FEM methods performed using ANSYS software, as well as drawing documentation of individual parts.

Within the scope of this thesis, a test stand Photo-CATCH for research on semiconductor photocathodes used at the spin-polarized electron injector of the superconducting Darmstadt electron linear accelerator S-DALINAC is constructed and brought into operation. Ultra-high vacuum conditions are achieved in all parts of the system. Atomic-hydrogen assisted low-temperature cleaning of cathodes in a chamber with base pressure better than 3 E-11 mbar is used for preparing clean cathode surfaces for negative electron affinity (NEA) activation. Using a standardised activation procedure, atomic-hydrogen cleaning of heavily contaminated bulk-GaAs samples is optimized to an upper limit of 10 kL hydrogen-dosage. Cleaning of samples has been performed with a dosage as low as 0.7 kL. Activation of photocathodes with Cs+O2 and Cs+Li+O2 have been studied in a dedicated vacuum chamber with base pressure better than 2 E-11 mbar. By using a 405 nm laser, quantum efficiencies above 25 % have been achieved from an NEA-GaAs photocathode. Oxygen-induced quantum-efficiency degradation of NEA cathodes has been investigated. A vacuum lifetime of (298+/-35) hours was observed in the activation chamber for a novel two-stage activation using Cs, O2 and Li. This system can provide photocathodes with high quantum efficiency and lifetime for polarized and unpolarized beam production at the 60 keV electron beamline of Photo-CATCH. Additionally, atomic-hydrogen cleaned cathode samples can be transported to the photoelectron source at S-DALINAC using a transport-vessel conceptualized in this work.