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514 Uppsatser om Compressive strength - Sida 1 av 35

Utveckling och dimensionering av en lastupptagande provningsram

ÅF Test Center in Borlänge had a need to expand their capacity for compressive and tensile strength tests. They wanted to do this by using a hydraulic cylinder, which they already possessed, to apply the force with. This required a load receiving structure. The aim of this work was to design and dimensioning a test bench for a cylinder marked NIKE 300 tons. The work would result in a completed design proposal on a test bench which could manage to run the compressive and tensile strength tests of up to 3000 kN.

Development of concrete compressive strength: a study of Swedish bridges constructed during the 20th century

Tryckhållfasthetsutveckling hos broar. En studie av svenska broar byggda under 1900-talet.

Inverkan av flisig krossballast på betong

Concrete is one of the world?s most common construction materials and is composed of 70-80 % stone material. Today crushed stone is used as aggregate in concrete in order to replace natural aggregates due to strong environmental reasons. Stone crushing yields flaky material and in this thesis studies are made on the flaky particle shape and how it influence properties of concrete such as workability, rheology and strength. The concrete recipes used in this thesis have fixed values, the only variable is the flakiness of the crushed stone.

MUSKULÄR STYRKA VID MULTIPLA REPETITIONER: : SKILLNADER VID STYRKETEST I BÄNKPRESS OCH LIGGANDE BÄNKRODD MED SKIVSTÄNGER AV OLIKA DIAMETEROMFÅNG

Introduction: A complex interaction between muscles, tendons, bones, joints and nerves are required for optimal function of the human hand. It is known that an individual?s grip strength is vital for performance of physical demanding tasks such as strength training with free weights. Strength training including a thicker grip around the bar may enhance the strength of the grip in the athlete without other special routines for grip strength development. The purpose of this investigation was to examine the difference in performance in multiple repetitions in two strength training exercises using two different sizes on the bar, to look for correlations between grip strength of the subjects hand and the amount of repetitions executed with two different size of the bar and finally the correlation of hand size and the amount of repetitions executed with two different size of the bar.Method: 15 strength training men (23,9 ± 4,1 years), underwent measurements of hand size, maximum grip strength, 1 repetition maximum (1RM), a 80 % of 1RM weight strength test with two different  bar sizes.Results: The results from the present investigation indicates a 21,1 % reduction of 80 % of 1 RM weight performance in repetitions executed in the bench press with the thicker diameter of the bar and a 66,2 % reduction in repetitions executed with a 80 % of 1 RM weight in the lying bench row with the thicker diameter of the bar.

Abrasiv nötning av polymerer tillverkade genom 3D-skrivning

Volvo Cars in Skövde manufacture and assemble Volvo engines. When attaching the ignition coil to all 4-cylinder engines, a special mounting tool is required. This mounting tool is currently manufactured from injection-molded polyoxymethylene (POM), a thermoplastic. It has been noted that the life span of the tool is shortened as a result of abrasive wear that occurs during the attachment process of the ignition coil.An investigation of the possibility of manufacturing the mounting tool with a 3D-printer is undertaken in cooperation with ÅF, a consultant to Volvo Cars. A literature study is first presented to introduce broader knowledge on the subject.

Den ultimata träningsmetoden?

Crossfit is a recently developed form of training which is based on a number of functional resistance exercises performed at high intensity, often to the point of muscular failure. Crossfit has since its introduction 30 years ago, reached vast popularity all around the world, including Sweden. Its practitioners considers Crossfit to be an effective training method for achieving a functional and total trained physique thru improvements in VO2max, muscle strength, endurance, balance and speed. Few scientific studies has been published in the subject which is why this study sets out to examine the effect of Crossfit on VO2max (measured with Åstrands submaximal cyclingtest), maximal strength capacity in lower- and upper body muscles (measured with 1 RM tests in bench press and leg press), rapid strength capacity and strength endurance capacity in upper body muscles (measured with push-up test in 30 seconds) and explosive strength capacity in lower body muscles (measured with sergeant jump test). Five women with an average of 33(±5) years of age all new to Crossfit, performed these tests at two separate occasions with a training period of four weeks consisting of 12(±3,67) Crossfit sessions in between.The result showed a significant improvement in the maximal strength capacity of the leg extension muscles (p=0,025).

Effekter av muskeluppbyggande träning på muskelstyrka och funktionsnivå hos personer med Multipel Skleros: en litteraturstudie

Multiple sclerosis (MS) is one of our most common neurological diseases. The development of the disease often make the affected persons live with it for a long time. There are two types of the disease, the first is a progressive type and the other is relapsing remitting. Strengthening exercises isn?t commonly used as a treatment method although muscle weakness and fatigue are common symptoms.

Finns det någon variation i CMJ som återföljs av förändringar i någon av pulsvariationerna och handstyrkan?

IntroductionSuccessful training is a key for athletes to make progress in their development. Training must not just involve overload, but also must prevent the combination of excessive overload plus inadequate recovery. Athletes can experience short-term performance decrement without severe psychological or lasting other negative symptoms. Too much hard exercise or too little sleep can cause overtraining, a condition in which the subject can prevent to be away from the sport for several weeks or months. Previous studies have detected that it is important to avoid overtraining.

Grundläggning med cellglas : En studie av byggtid och lönsamhet

This report describes a new foundation method and compares it with a traditional founding of concrete. This new method is called the Koljern technique and uses cellular glass which is called Foamglas. The Foamglas is compounded to founding elements by lightweight steel beams. Foamglas is an insulation material with high Compressive strength, and is rot, insect, vermin and acid proof. The cellular glass is also fire proof and watertight, which makes it a very good construction material.The report contains a study of a number of cases for which the Koljern technique is compared with a foundation of concrete.

Dynamisk styrketräning av M : Quadriceps femoris hos personer i övre medelåldern

AbstractElderly people are going to be a growing number in Europe. Between one third are going to be 60 years or older at 2025. For Sweden the situation is going to be similar. A reduced muscle function could lead to complications for the individual to perform daily tasks and will lead to a higher rate for falling and getting bone fractures. The positive sides are that for men and women there are a possibility for maintaining physical function and strength even in older years.

Icke utövande Kvinnors relation till styrketräning : Om Kunskap, Fördomar, Arbetsgivaruppmuntran och Manslukt

In this study it has been investigated what is missing in non-strength training women to begin exercise regular strength training. It has also examined the level of knowledge about the health benefits and the employer's encouragement to maintain good health. The study was designed in a qualitative methodology and data collection was designed in form of semi-structured interviews. Six women were interviewed between the ages 22-51år. The results showed that women possessed a very low level of knowledge about strength training and also fears and prejudices existed among them.

Optimering av sintrade kugghjul

Powder Metal (PM) gears are machine element components which operate under the same principle as conventional gears, but, due to their intrinsic material characteristic need to be designed slightly different, and its manufacturing process offers advantages previously unobtainable by conventional steel gear manufacturing methods. The use of PM in similar applications, such as synchronous hubs, makes them a suitable candidate for production in such material. The current master thesis work focuses on gear design using PM by utilizing finite element method (FEM) to reduce weight and inertia taking into account root bending strength and tooth deflection.First a topological optimization is used to determine feasible candidates for different web designs which have as objective to reduce volume, similar topologies were shown during different loading conditions; and hence, this topology was chosen as a suitable candidate. A shape optimization of the topological candidate was performed having as state variables root bending strength, independent for compressive and tensile side of the tooth loading; and tooth deflection, which in concept can be correlated to static transmission error (TE).Another aspect in this thesis analysed is the possibility to incorporate non-trochoid root geometry, a trochoid root is always present when machining with a hob, into the gear root and hence reduce the stress concentration here. Due to the use of PM, a non-symmetric optimized root can be achieved and hence be optimizing compression and tension.Results showed significantly lower inertia, for example certain results showed 40% reduced when compared to solid gear, with adverse effects as increase in tooth deformation and increase in maximum principal stress.

Betongens hållfasthetsutveckling vid användning av olika ersättare för portlandklinker : En laborativ studie

Tillverkning av portlandklinker står för ungefär fem procent av världens totala koldioxidutsläpp. Det finns därför ett allmänt intresse att minska användandet av portlandklinker. Klinkern kan antingen ersättas av andra cementerande material, eller så kan nya cementsnåla recept utformas. I den här rapporten har två cement med inmald flygaska respektive slagg från Cementa AB undersökts. För att undersöka klinkerersättnings-materialens potential har tester för tryckhållfasthet, uttorkningskrympning, bindetid, värmeutveckling och arbetbarhet utförts.

Ett varumärkets styrka och dess distribution : en studie genomförd med utgångspunkt från varumärken som säljer en livsstil

Background: A strong brand is becoming an increasingly important factor when surviving on a competitive market. A strong brand can therefore be considered a strategically important resource. The relationship between a brand's strength and its distribution can decide the future of a brand in the long run. Lifestyle branding is becoming a more popular way of differentiating ones brand from the competition. Purpose: The purpose of this thesis is to identify factors which according to the lifestyle brand owners are central when measuring the strength of a brand.

Bakhjulsupphängning, fyrhjuling

Highland Group AB was helping a customer of theirs to create an All-Terrain Vehicle (ATV), a project Highland has never been involved with before. For the wishbone arms of the wheel suspension, traditional manufacturing methods and tubes with cylindrical or square shaped cross section was preferred. We performed a simulation where the ATV was driving on a bumpy road too see the forces involved. With the results we proceeded to calculate the strength of the concepts to find out which is best suited for the tough environment in which the ATV is used. The concept that turned out to be the best was a wishbone made of circular cross section, which had good structural strength and did fulfill the demands that we required for the construction.

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