Floor surface in pig facilities can have an impact on animal welfare and pig health, as it can cause the pig physical damage and thereby increased risk of infectious diseases and lameness. The development of pig housing systems has resulted in a decreased use of bedding. It seems hard to find the optimal floor in farrowing pens, as it must suit both the sow and piglets. The floor friction needs to be adequate to avoid slips and at the same time should the floor be non-abrasive. Abrasions and lesions caused by the floor are not only causing the animal suffering, but are also negative from an economical aspect.

The tribo system ice-curling stone was investigated in order to understand the mechanisms behind the stones' behavior on the ice sheet. The problem with non-identical stones should also be addressed.The stone curls, that is, its sliding path deviates from a straight line to the right for a clock-wise rotation and to the left for a anti-clock-wise rotation. Several mechanisms to explain this behavior have been proposed over the years but none has been successful.By carrying out experiments at the local curling rink and studying silicon castings of ice- and stone-surfaces with scanning electron microscopy and vertical scanning interferometry, it has been decided that the curl is not due to dry friction, ice-debris or the difference in friction on the left and right side of the stone. The side force comes from the fact that the friction is higher at the back of the stone than at the front.The contact between stone and ice is never completely dry, nor in the hydrodynamic lubrication regime. It is probably a combination of hydrodynamic lubrication and a contribution from mechanical scratching of the ice.

A new material model, for the FE-program ADINA, has been verified against twoexperiments. One unreinforced concrete beam and one reinforced concrete beam.The model, DF-concrete, has the possibility to estimate true concrete. However theresults indicate that in order to be sure that the estimations are true, there ought tobe data from the true concrete to verify against.Two FE-models have simulated the behavior of a ring-shaped part of the nuclearcontainment vessel. The results from the first, frictionless, model agree with similarsimulations and hand calculations for high pressures in the containment vessel. Thesimulations of the nuclear containment vessel show cracking in the concrete after10-11 bars of over pressurization.

Future emission legislation puts great emphasis on increasing the efficiency of the engine, thereby reducing fuel consumption. The tribological contact between cylinder liner and piston ring is where an great amount of energy is lost due to friction, and by reducing these losses an reduction in fuel consumption can be achieved.The aim of this thesis was to evaluate the tested piston ring coatings against a plasma sprayed cylinder liner and rank these combinations of materials for friction and wear resistance. The coatings that were tested was Cr + Al2O3, (Al,Cr)N, two types of CrN and WC / C.The experimental tests were performed with a so-called pin-plate, where used oil with addition of an acidic mixture of sulfuric and nitric acid to mimic the acidic condensate formed when exhausts recirculate, were added with a continuous flow. The results were then analyzed by weighing, studies by optical microscopy and scanning electron microscopy (SEM) and profile measurements.The results from each material combination were that the plasma coated cylinder liner wears too aggressively in order to yield a ranking of the piston ring coatings based on the parameters of friction and wear resistance. It is therefore proposed that an alternative coating on the cylinder liner should be developed, lacking the large abrasive wear on piston rings and that can withstand the corrosive environment resulting in engines equipped with EGR.

Future emission legislation puts great emphasis on increasing the efficiency of the engine, thereby reducing fuel consumption. The tribological contact between cylinder liner and piston ring is where an great amount of energy is lost due to friction, and by reducing these losses an reduction in fuel consumption can be achieved.The aim of this thesis was to evaluate the tested piston ring coatings against a plasma sprayed cylinder liner and rank these combinations of materials for friction and wear resistance. The coatings that were tested was Cr + Al2O3, (Al,Cr)N, two types of CrN and WC / C.The experimental tests were performed with a so-called pin-plate, where used oil with addition of an acidic mixture of sulfuric and nitric acid to mimic the acidic condensate formed when exhausts recirculate, were added with a continuous flow. The results were then analyzed by weighing, studies by optical microscopy and scanning electron microscopy (SEM) and profile measurements.The results from each material combination were that the plasma coated cylinder liner wears too aggressively in order to yield a ranking of the piston ring coatings based on the parameters of friction and wear resistance. It is therefore proposed that an alternative coating on the cylinder liner should be developed, lacking the large abrasive wear on piston rings and that can withstand the corrosive environment resulting in engines equipped with EGR.

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.

Våta kopplingar används i automatiska transmissioner för att överföra vridmoment. De primära komponenterna i en våt koppling är de oljesmorda pappersbaserade friktionslamellerna och separationslamellerna gjorda av stål. Volvo Construction Equipment (Volvo CE) utvecklar och bygger automatiska powershifttransmissioner med våta kopplingar till sina anläggningsmaskiner. Volvo CE och Luleå Tekniska Universitet (LTU) bedriver tillsammans forskning om våta kopplingar som involverar pappersbaserade friktionsmaterial. De två vanligast förekommande materialen i produktion, i detta examensarbete benämnda som material A och B, testades i en testrigg på LTU.

The thesis evaluates a new kind of bearing arrangement in a traction motor that ABB hasdeveloped. Since the arrangement is designed in a new and innovative way it needs to beevaluated to see if it is safe to use. In today?s traction motors, bearings with a big internalclearance (C4-clearance) are used. The basic idea of the new arrangement is to reduce the fitsbetween the bearing and shaft/house.

The purpose of this work is to find out if the suctionvalve to the salivaejector for dental equipment in a simple way can be improved or if a new design is needed. The result of the examination of the suctionvalve shows that the friction between the piston and the seal is high and that this causes the valve in a few cases sheaves. The study concluded that only small changes in material or detail, improve the component..

 AbstractThis Master?s thesis analyses the dynamics of the medieval counterweight lever engine, ortrebuchet, a type of mechanical artillery. The purpose is to study the differences between different types of these machines, and see if computer simulations can be used to validate preserved advice on construction. Simulations include machines with a fixed counterweight, a hinged counterweight and a combination of both counterweights.Due to the almost complete lack of archaeological finds and insufficient historical source material there are still, after more than a century of research, many unanswered questions concerning the design and performance of these machines.The present study is based on an analysis by Jahsman (2004). A more detailed mathematical model employing Coulomb-friction is used.

During this master thesis, wear and friction properties for the high-temperature alloy Kanthal APMT were studied. The results were also compared to 253MA. The initial tests showed, among other things, that the surface fineness of the muffle tubes matters in real applications like conveyor belts. A 253MA-sample wear-tested against a 253MA-tube showed lowest wear at 900°C while a pre-oxidized APMT-sample wear-tested against a APMT-tube had the lowest mean value of the friction force at 1100°C, compared to all other tests..

The purpose of this work is to find out if the suctionvalve to the salivaejector for dental equipment in a simple way can be improved or if a new design is needed. The result of the examination of the suctionvalve shows that the friction between the piston and the seal is high and that this causes the valve in a few cases sheaves. The study concluded that only small changes in material or detail, improve the component..

Piled friction soil show a set-up which is increasing with the time after installation. The cost could be reduced if the set-up had been taken into account when designing but in Sweden it is very unusual to do that. Previous studies showed that set-up can vary between 25 % and 75 % during the first 90 days after pile installation. This showed that the effect of the phenomenon is difficult to predict. A study involving five projects have been carried out by specifying certain parameters like pile type, method for pile installation and test method for measure the bearing capacity in friction soils located in Sweden.

By our employer Camatec Industriteknik AB have we been given the assignment to continue with the previous work ?Design of strip feeder?. Our goal with this work is to come up with a design basis for a strip feeder.Functionally a strip feeder consists of two rollers which with the aid of the friction between the strip and the coating on the roller create a strip force that pulls the strip through the working progress.Demands on this project:? 10 ? 600 mm in strip width and 0,1-1 mm in strip thickness.? Minimum 30m/min in production speed.? A maximum strip force on 30-40 kN.? The cost of the strip feeder?s components is to be considered of economy and quality.The need of a strip feeder occurs when the coil doesn?t manage to feed or pull the strip before or after a working process. The strip can otherwise be exposed by a permanent yield deformation or a change in the strip material if it?s pulled trough the working process only by the on ? and of-coils.

De senaste årens långa och kalla vintrar har lett till ett ökat antal halkolyckor. Genom att undersöka halkolyckors utsträckning samt halkskydd som fanns tillgängliga konstaterades det att ett behov av nya halkskydd fanns. Enkäter för att ge svar på användning av halkskydd togs fram och svar från personer i åldrarna 20-65 visade att man överlag inte använde halkskydd. I stor utsträckning berodde det på halkskyddens dåliga kvalité och den negativa stämpeln som fanns på dem . Textila material undersöktes för att finna lämpliga egenskaper.