The polymer PTFE has become an important and widely used sealing material in the valve industry in recent years. It provides good strength and low friction, but it is sensitive to stress relaxation, i.e. loss of stiffness with time. This in turns may cause problems with leaking seals. The objective of this master’s dissertation is to perform a stress analysis of the PTFE sleeve used in an indust

Glulam arches can be used when designing structures with large spans such as halls or arenas. Wood has low density compared to steel and concrete which keeps down the dead weight of the structure. The cross section of glulam arches is often built up as a box-section for efficiency reasons. However, wood shows strongly orthotropic behavior where maximum allowed stress perpendicular to grain is only

Parallel computing is becoming more and more important in modern Finite Element Software. As problems grow larger, computation on a single processor may not be fast enough. To overcome this problem, one can utilize parallel programming using e.g SMP-machines or clusters. Furthermore, when local compute resources are scarce, it can be quite convenient to take advantage of non-local resources for pe

I dag finns ett flertal metoder för jordförstärkning i samband med grundläggning av vägar och hus. För förstärkning av kohesiva jordar är bland annat stenpelarmetoden användbar. Stenpelarförstärkning är en etablerad förstärkningsmetod i stora delar av världen. Metoden härstammar från Tyskland där vibrationsbaserad förstärkning utvecklades under 1930-talet. En stenpelare byggs upp genom att sten

In 1994 the Swedish Construction Code, BKR, was changed from being based on material to being based on function. This permitted constructing multi-storey buildings with a bearing framework made of wood, which had been prohibited since the end of the 19th century. There is now a growing in- terest of using wood as a construction material. In Växjö four seven-storey buildings, Limnologen, are under

Ökad industrialisering har inneburit stora effektivitetsvinster vid nybyggnation av flerbostadshus. Det finns dock ännu ingen metod för standardisering och industrialisering av grundläggningen, vilket gör den till en relativt kostsam och resurskrävande del av byggprocessen. Skanska har startat ett konceptbygge som kallas Moderna Hus. Syftet är att genom standardisering och industrialisering kapa

Following changes on a European level, there are plans to also in Sweden reduce the characteristic value of shear strength of glued-laminated timber. In Sweden, a decrease of approximately 30% from a characteristic value of 4.0 MPa (for glulam L40) to 2.5 or 3.0 MPa is planned. This would mean that wood would lose competitiveness against other construction materials such as steel and concrete. T

Today a dynamic analysis is often performed with the use of advanced finite element software. An advanced model normally produces precise results. Analyzing these large models of bridges is however time consuming and a detailed description of the geometry, supports and material properties must be known. In an early stage of a project a reduced model could significantly reduce the time needed to perf

This report is dealing with time dependent settlements calculated with numerical methods and subsequent comparisons with field measurements. The numerical computations in this report have been performed using Plaxis, a two-dimensional numerical program based on the finite element method. Plaxis is very practical for solving complex geotechnical problems involving settlements or slope stability.

The work presented in this thesis deals with investigation of methods to evaluate simultaneous moment and normal force capacity for symmetrical and unsymmetrical thin walled aluminium beams. The beams are supplied by Sapa Building System AB and is used in their glass facade system SFB 4150. The system is constructed in a way that makes it possible to make large glass facades. It is then of interes

Until recently, the general level of detail in full car crash models has not allowed a physical modeling of rubber bushings with solid elements. This is partly because of the difficulty in modeling the complex characteristic of rubber, but also due to limited understanding of the mechanical properties of rubber materials. The main focus of this Master’s thesis project is to develop a new and im

Foundations of buildings and structures are laid with various methods, both deep and shallow foundations. Piling is the most common method of deep foundations while spread footings are often used in shallow foundations, especially in buildings with column frame. An alternative is to use a composite pile foundation where piles and spread footings or piles and a base slab are used to carry the loads

Examensarbetet behandlar fenomenet momentreduktion. Reduktionen uppstår då en spontvägg deformeras och krafterna i jorden omfördelas. I arbetet har fyra olika spontdimensioneringsmetoder behandlats som på olika sätt leder till ett dimensionerande moment. Tre av dessa är handberäkningar och den fjärde är en jämförande beräkning som görs i finita elementprogrammet PLAXIS. Två av handberäkningsmetThe thesis deals with the phenomenon of moment reduction. The reduction occurs when a sheet pile wall deforms and forces of the soil are redistributed. Four different methods of designing sheet pile walls are treated that in different ways lead to a design moment. Three out of these design methods are made by hand calculations and the fourth is a comparative assessment carried out in the finite

The objective of this dissertation is to implement a large part of CALFEM functions to Python and to explore libraries and software in addition to NumPy needed to achieve a comparable environment for CALFEM. No actions will be taken to improve or change existing programming. Comparison of code and description of the main differences when writing in Python is done to simplify the transition for exis

Limträbågar med lång spännvidd har ofta ett väldigt högt och slankt tvärsnitt. Detta medför risk för vippningsinstabilitet. En jämnsymmetrisk belastning av bågen ställer oftast inte till något problem, men då bågen belastas osymmetriskt uppkommer stora böjmoment som ökar risken för instabilitet markant. Raka balkar som belastas med punktlaster eller utbredda laster får ett tryck i balkens överkanGlulam arches with long span often have a very high and slender cross-section. This may cause lateral torsional buckling of the arch. A symmetrical loading doesn’t usually become a problem, but if the arch is loaded asymmetrical there will be large bending moments that increases the risk of instability significantly. Straight beams that are subjected to point loads or distributed loading will be s

Mechanical systems can be modeled by connecting rigid bodies with loads and other components. Prescribed motions and initial values can be defined in a system. The behaviour of the rigid bodies can then be studied and their motions can be computed. If a body is elastic the motion of some defined points are not identical to a rigid body when loads are affected. To model a mechanical system the dyna

Max-lab is a national laboratory operated jointly by the Swedish Research Council and Lund University. Nowadays, the Max project consist of three facilities (three storage rings): MAX I, MAX II, MAX III and one electron pre-accelerator called Max Injector. A new storage ring is needed due to improved nanotechnology. MAX IV is planned to be the next generation Swedish synchrotron radiation facilit

At present there are no concrete guidelines how to calculate the pressure resistance capacity of the timber at the load perpendicular to grain. The test options ASTM, CEN and ICO gives three different results in testing of an equal body. With this knowledge the value for the characteristic compressive strength capacity of the pressure perpendicular to the grain will be reduced to 2.7 MPa. The reduc

Ett viktigt moment vid tillverkning av kartongmaterial till livsmedels-förpackningar är laminatorn. I laminatorn täcks råpappersmaterialet av smält polymer i det så kallade nypet. Nypet i sin tur består av en stor kylvals och en mindre gummiklädd nypvals. Genom att styra kraften som verkar på nypvalsen kan kontakttrycket i nypet regleras. Vinkelhastigheten med vilken nypvalsen roterar är stor och

The Swedish government has specified a goal for the Swedish wind power that in 2020 it will generate 30 TWh of energy per year. This should be compared with the present energy produced from wind power of 2.5 TWh / year. To meet these goals, several thousand new wind turbines have to be built. Today, we build the most land-based wind turbines on strong and stiff soils, but probably in the future