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37 Uppsatser om Stiffness - Sida 1 av 3
Mätningar av statiska och dynamiska egenskaper för bakaxel.
To design new and high tech products the engineers rely more and more on computer based simulations to investigate the properties and behavior for a component or system.To verify these computer based simulations the dynamic properties for the components of the drivetrain needs to be verified. Therefore measurements of the Stiffness and vibrations for the rear axle has been performed. This report show how the measurements has been implemented and evaluated, along with some interesting results for the rear axles properties.The static Stiffness for the drive shaft along with the axle-gear has been determined. It is found that the Stiffness for the whole rear axle is near the Stiffness for the drive shaft, which means that the drive shaft becomes the dominant component of the system and affects the rear axle Stiffness the most. The measured Stiffness of the driveshaft is close to its theoretical Stiffness.The Stiffness for solely the hypoid-gear have been calculated using the Stiffness for the rear axle and driveshaft, and thus has a range for the Stiffness of the hypoid gear been determined.The backlash for the whole rear axle and for some individual components has been determined, where the backlash between pinion and crown-wheel has negligible impact on the total backlash.Measurements of the crown-wheel and pinion movements have been conducted, where the direction of movement is consistent with the theoretical direction of the forces.The vibration measurements show that the vibrations are more severe at certain rotational speeds.
Lätta bromsok
SAAB Automobile ABis a car manufacturer within General Motors corporate group. SAABAutomobile ABhas a big part of the responsibility for the brake development in the corporategroup. The car industry is facing harder environmental requirements, which influence the brakedevelopment. The focus is to develop brakes with low drag and sustained brake feeling andperformance. Important characters for the brake caliper are high Stiffness and low weight, highStiffness results in high performance and low weight is important because it is unsprung mass.This thesis investigates the possibility to improve the performance of the brake caliper for aGMproject.
PRAKTISK BESTÄMNING AV KLÄMKRAFT OCH FRIKTION I SKRUVFÖRBAND
This report reflects an examination work performed for Getrag All Wheel Drive AB during the spring of 2005. Among the companies range of products there exists some concern regarding the amount of clamping force and friction on bolted joints caused by the assembly torque.The aim of this project has been to determine if there is a simple way in which to identify and then practically apply testing methods for clamping force and friction through utilization of existing testing equipment.Three separate methods of clamping force and friction determination have been tested in rear drive unit, RDU, at a 30 Nm assembly torque. A fourth and final method, screw elongation with ultrasound, has been used as reference. The methods are:?Torque-Tension test.?Screw elongation with micrometer.?Joint Stiffness test.?Screw elongation with ultra sound for reference.The results from tests can be viewed in table below.MethodTorque-TensionMicrometerCs=318 kN/mm Assembled with torque wrenchMicrometerCs=318 kN/mm Assembled on lineUltra-soundCS=311 kN/mm Ultra- soundCS=318 kN/mm Joint StiffnessTheoreticalClamping force-21,8 kN17,6 kN17,3 kN17,6 kN17,1 kN17,3 kNFriction-0,110,1470,1530,1470,1520,149.
Konceptstudie av en kompakt Picker robot
Picker robots are often mounted close to each other above a conveyor belt. To be able topack robots even closer, it is desirable to reduce the footprint of the robot?s base. One way toachieve this is to skew the arms of the robot which makes it possible to move them closer toeach other.This Master Thesis has been carried out at ABB Corporate Research. The purpose is toevaluate the benefits and drawbacks for the idea of making today?s Picker robot morecompact by skewing the arms.
Tollarsjuka hos hund : en retrospektiv studie med journalsammanställning av 18 hundar
?Tollarsjuka? is a disease with a suspected immunopathological background seen in Nova Scotia duck tolling retrievers. Pyrexia, lameness, Stiffness and joint- or musclepain are typical clinical signs.
The purpose of this study is to describe case histories from dogs with a possible evidence of ?tollarsjuka?. 18 private dogs were included in this report.
Generalised Stiffness, lameness and fatigue were the most frequent manifestations of the disease.
Komfortsanalys med hänsyn till vibrationer orsakade av människoaktiviteter. : Ett modernt dimensioneringsproblem för huskonstruktörer
Comfort analyses regarding human induced vibrationsIt is not too common among civil engineers in Sweden to perform comfort analyses considering the vibrations caused by human activities. In addition, the Swedish standards lack requirements to be used for comfort analyses in design of floor-systems. The demand for large spans in combination with slender slabs, is today a reason to investigate the floor-system constructions, in order to prevent disturbing vibrations and oscillations.The purpose of this thesis is to create a guide for how a comfort analysis, considering vibrations, should be implemented. Göran Svedenbjörk who is an expert in structural dynamics has been interviewed where he presents his latest project Värtaterminalen and answers some questions about vibrations due to human activities.Floor-systems, consisting of concrete slabs supported by steel or concrete beams, have been investigated with simulations in the finite element program Abaqus. In the simulations, the influence of various factors on the natural frequency of floor-systems and the acceleration level caused by dynamic loads, is studied.
Utvärdering av en Magnetic Harmonic Traction Drive
In this report a new gear concept is evaluated using the magnetic finite element method (FEM)software MagNet and Ansys as well as the mechanical FEM software Abaqus. The gear conceptis evaluated in terms of maximum torque capability, torsional Stiffness, gear ratio and efficiency.ABB Corporate Research has proposed a new gear concept which should be less expensive thangearboxes used today. The new concept is called aMagnetic Harmonic Traction Drive and usesthe principles of a harmonic drive gear to achieve a high reduction ratio. The gear conceptreplaces the wave generator used in traditional harmonic drives with magnets and uses tractioninstead of gear teeth to transfer the torque. The main components in the gearbox are the magnets,the flexspline, the magnetic portion and the circular spline.
Vegetarisk kost - ett möjligt behandlingskomplement för symtomlindring vid reumatoid artrit?
Sahlgrenska Academyat University of GothenburgDepartment of Internal Medicine and Clinical NutritionAbstractTitle: A vegetarian diet, a possible treatment complement for relief of symptoms ofrheumatoid arthritis? A systematic review.Author: Alexandra Ahlsén and Caroline ForsbergSupervisor: Mette AxelsenExaminer: Anna WinkvistProgramme: Dietician study programme, 180/240 ECTSType of paper: Examination paper, 15 hpDate: May 22, 2012Background: Rheumatoid arthritis (RA) is a chronic remitting polyarthritis that is relapsing.Symptoms are inflammation of the joints with pain, Stiffness and degradation of joint tissue.In some cases, also other parts of the body are involved. The treatment consists ofmedications to reduce pain, inflammation and degradation of joint tissue. Today, the offerednutritional treatment is primarily focused on meeting energy requirements and nutrient needs.The diet has also been discussed as symptomatic treatment, and one of the factors believed toinfluence the symptoms is meat.Objective: To assess the evidence as to whether a vegetarian diet affects the symptoms ofrheumatoid arthritis, and if so, to suggest how it can be implemented in practical dieteticswork.Search strategy The databases used in the literature search was PubMed, Scopus, and AMED.The search words used were: "rheumatiod arthritis", "vegetarian", "vegan", "diet", "meat" and"animal protein".Selection criteria: Studies investigating a vegetarian diet on the symptoms of RA wereincluded. Only RCT, clinical trial, controlled clinical trial, human studies and original articlesin English or Swedish were included.
Elasticitetsmodulen i en kalkstabiliserad vägterrass : en fältstudie
Stabilization of subgrade is an internationally common technique to improve the characteristics of a soft soil. Improving the Stiffness and bearing capacity of the subgrade enables the pavement to be designed with reduced depths of subbase and basecourse aggregates. This makes the stabilization technique both economically and environmentally interesting. Both natural and stabilized soils have high inherent property variability that should be considered when the characteristic value is derived. By analyzing the spatial variability in stabilized and natural subgrades it is possible get the parameters needed for reliability?based modeling of soil properties.
Inverkan av tvång i gjutfogar och i betongkonstruktioner på
elastiskt underlag: Influence of Restraint in Casting Joints
and in Concrete Structures on Resilient Foundation
In this report, the risk of cracking in joints and/in adjacent concrete is estimated by checking shear forces in joints and the ratio between the actual maximum principal stress ant the actual strength of the concrete. The shear force has been estimated both by simple methods as well as by two-dimensional calculations. The risk of cracking in the concrete and/or in the joints is estimated with the computer program ConStre. The restraint from a resilient foundation or rock on a young concrete construction is estimated by a simple method that is exemplified. It is shown that the restraint can be neglected in some cases.
Höga hus med deformerbara fundament på pålar : Pålkrafters avvikelse visavi klassisk teori samt förskjutningar beroende av vindlast
When forces in foundation piles are calculated according to classic theory, thefoundation are assumed to be infinitely rigid which means that the foundation will notbend. High buildings need their whole width to be stable and use the ground floorwall as a foundation. But when, for example windows are needed in the ground floorwall, the Stiffness of the foundation decreases which change the forces in the piles. Inthis report the difference of pile forces versus classic theory has been analyzed, and ifpile forces can be calculated as in classic theory. Further on, the effects of the wallmovement were analysed and how the buildings crack safety would be affected by themovement at the ground floor.
Specialidrott eller inte? : Kan elever från riksidrottsgymnasiet i karate jämföra sig med svensk karate elit?
SammanfattningInledning: Specialidrott har funnits i skolvärlden sedan 70-talet och har lett till att många ungdomar har kunnat kombinera skola och elitidrottssatsning vid sidan om varandra. Det har skapats RIG (riksidrottsgymnasier) och ämnet specialidrott har lagts till som en kurs på gymnasieskolan. Målet med RIG var att göra det möjligt för talangfulla ungdomar att kombinera elitidrott med gymnasiestudier då gymnasietiden anses vara en brytpunkt för när elitsatsningen börjar. Att gå på ett RIG innebär även att få träna väldigt mycket och tävla med många av de bästa i samma åldersgrupper. RIG-systemet har producerat många svenska elitidrottare i olika idrotter.
Analys av instyrning och rolldynamik
When driving hard and cornering on a circuit good control of a car?s roll is desired, so the car reaches steady state quickly but yet in a controlled fashion. This control is mainly given by the combination of the cars springs, shock absorbers and anti-roll bars.The aim of this report is to investigate, analyze and measure a Porsche Boxster?s turn in behaviour and roll dynamics as well as with the aid of simulation results give suggestions for improvement of the previous mentioned combination.Two different simulations were made, one based on a simpler model that was based on an evolved version of the bicycle model in Matlab and one was more advanced model in the simulation software rFactor. Measurements of the real car was made using a GPS-based measurement system.
Testbänk för luftlager
Test bench for air bearingsThis thesis work consisted of bringing forward and defining the test parameters relevant for a test bench and constructing a test bench that can test and verify the largest existing air bearings that are of use in Micronic Laser Systems AB machines. Because the knowledge about air bearings is limited it is thought that with the help of the test bench the knowledge would increase and in that way improve the air bearings.After learning more about air bearings and their purpose at Micronic Laser Systems AB, I started the concept phase for the test bench. For each part in the test bench I consulted my two tutors, Torbjörn Hedevärn and Johan Bergqvist, at Micronic Laser Systems AB. The final concepts where documented as 3D-modells in Solidworks and some of them have been tested in Solidworks FEM-program.The test bench is designed so that, with the help of a pneumatic cylinder, 25 kilo weights are placed on the air bearing to test its Stiffness, damping and the pressure performance under its surface area. To test these parameters the test bench has to have a pressure meter, accelerometer and a microcator.
Naturlig haptisk kraftåterkoppling från volymdata
As the volumes are entering the world of computer graphics the pure volume visualisation becomes a more important tool in for example research and medical applications. But the advance in haptics --- force feedback from the computer --- is behind. In volume haptics no equal to the proxy method so popular in surface haptics has yet emerged. Some implementations of volume haptics even use surfaces as intermediate representations so that surface haptics can be used.The intention of this work was to create natural feeling haptic feedback from volumetric density data using pure volume haptics. The haptic algorithm would be implemented in Reachin API for the Reachin Desktop Display, together with other parts to build up a usable volume visualisation environment.To achieve the feeling of Stiffness and friction dependent on tissue type, a proxy based method was developed.