The objectives of this thesis comprise of overcoming the challenges in designing lightweight welded structures such as material selection, choice of fatigue design methods, and increased performance by using improvement techniques. Material selection of welded joints is dependent on the filler and base material strengths. Partially and fully penetrated cruciform and butt welded joints were designed in under-matching, matching, and over-matching filler materials. Base material steel grades were S600MC, S700MC, and S960. Current design rules are developed for welds in steel up to yield strength of 700MPa. Therefore, design rules in Eurocode3, AWS d1.1, and BSK 07 were verified and recommendations for developing design rules for designing welded joints in S960 were concluded. Numerical methodology for estimating static strength of welded joints by simulating heat affected zone was also developed. Another objective of the thesis work was to overcome the challenges in selection of fatigue design methods. The available design curves in standards are developed for uniaxial stress states, however, in real life the welds in mechanical structures are subjected to complex multiaxial stress states. Furthermore; weld toe failures are frequently investigated, weld root failures are seldom investigated. Therefore, in this work the multiaxial fatigue strength of welded joints failing at the weld root was assessed using experiments and various nominal and local stress based approaches. Butt welded joints with different weld seam inclinations with respect to applied uniaxial loading were designed to assess the root fatigue strength in higher multiaxial stress ratio regime. The fatigue strength of multi-pass tube-to-plate welded joints subjected to internal pressure only and combined internal pressure and torsion in and 90° out of phase loading was also investigated. Test data generated in this thesis was evaluated together with the test data collected from literature. Last objective of the thesis included investigation of the increased performance in fatigue strength by post weld treatment methods such as HFMI. The behavior of residual stresses induced due to HFMI treatment during fatigue loading is studied. Numerical residual stress estimations and residual stress relaxation models are developed and the effect of various HFMI treatment process parameters and steel grade on the induced residual stress state is investigated. Specimens studied were non load carrying longitudinal attachments and simple plates. Residual stresses in both test specimens were measured using X-ray diffraction technique. / <p>QC 20170206</p>

In this study an automated multidisciplinary design optimization code is developed for the minimum weight design of a composite wing box. The multidisciplinary static strength, aeroelastic stability, and manufacturing requirements are simultaneously addressed in a global optimization environment through a genetic search algorithm. The static strength requirements include obtaining positive margins of safety for all the structural parts. The modified engineering bending theory together with the coarse finite element model methodology is utilized to determine the stress distribution. The nonlinear effects, stemming from load redistribution in the structure after buckling occurs, are also taken into account. The buckling analysis is based on the Rayleigh-Ritz method and the Gerard method is used for the crippling analysis. The aeroelastic stability requirements include obtaining a flutter/divergence free wing box with a prescribed damping level. The root locus method is used for aeroelastic stability analysis. The unsteady aerodynamic loads in the Laplace domain are obtained from their counterparts in the frequency domain by using Rogers rational function approximations. The outer geometry of the wing is assumed fixed and the design variables included physical properties like thicknesses, cross sectional dimensions, the number of plies and their corresponding orientation angles. The developed code, which utilizes MSC/NASTRAN&reg / as a finite element solver, is used to design a single cell, wing box with internal metallic substructure and composite skins.

Although high strength steels represent yield strength up to 1300 MPa, welded structures reveal lowerstrength values. The strongest commercially available electrode provides the yield strength of about900 MPa. Therefore, in welded steels with strength above this type of filler metal, achieving anacceptable global strength is a crucial issue. In this master thesis, affects of different welding procedures on static strength of welded jointsof Weldox 960 and Weldox 1100 steels, were studied. These steels are produced by SSAB inOxelösund. Meanwhile, finite element method analyses were applied in order to investigatethe static strength behavior of such weldments under uniaxial tension. The welding parameters which were selected as variables are:  Heat input Weld joint geometry Filler metal When weld metal is undermatching in strength levels than the base material, by applyingtension the soft weld metal begins to deform before parent metal. At that point thedeformation of resulted soft zone, including the weld metal and the heat affected zone, ishindered by high strength parent metal. Thus, uniaxial stress caused by uniaxial load isconverted to multiaxial stress. This conversion in tension results in increase in the staticstrength of weldment. The increase in strength is emphasized by increase in the width of thewelded joint while the thickness of the plate is kept as constant. After experiments and performing FEM studies, it was revealed that the static strength ofWeldox 960 welded joints approaches towards the tensile strength of parent metal by increasein the width of the weldment. In Weldox 1100 joints; a slight increase in tensile properties ofthe weldments, when the width of the sample increases, was observed.

This master thesis studied the possibilities of implementing new handbook methodologies for sizing of corner and bathtub attachments with respect to static strength.  Parametric studies of corner and bathtub attachments were performed in order to examine the effect of boundary conditions and vital dimensions with respect to static strength. The parametric studies were performed by solving FE-models of attachments with different dimensions. Variables such as flange thickness, end-plate thickness, end-plate length and total attachment width were varied in order to identify geometric trends for prediction of cross-sectional loads.  The FE-models consisted of a bolt, washer and attachment assembly. The bolt was subjected to pre-tension and contact conditions were applied in between each part. The parametric study examined the cross-sectional loads of critical cross sections of the end-plate, bolt, flanges and back.  The parametric study of the bathtub attachment resulted in verification of critical failure modes from earlier handbook methodology, as well as a foundation for a new handbook methodology for sizing with respect to static strength. The parametric study of the corner attachment resulted in an identification of critical failure modes. The non-symmetric configuration of a corner attachment was found to result in larger load distribution in the bolt shank cross section.

This diploma thesis deals with the calculation of composite wing loading and its stressanalysis. Furthermore work contains design of static strength test wing.

Title: Changes in handgrip strength in relation to laterality at indoor youth climbing course Objectives: The aim of this diploma theses is to investigate whether regular climbing activity of children at age 7-11 leads to development of handgrip stength or its endurance with respect to laterality. Also if climbing leads to symetrical strenghtening of upper limbs. Methods: Group of 14 children at age 7-11 participated in a climbing course once a week for 3 months. Maximal grip strength was measured, persistence in pressing hand over 30 seconds and evaluation of laterality. First testing was done in October 2016 and second after 3 months in January 2017. Results: The research involved 13 right-handed and 1 left-handed participant and degree of laterality remained unchanged. Grip strength of dominant upper limb was stronger in 10 children from 13 (October 2016 - first measuring) at the first measurement. Our results suggest that climbing activities for three months, according to statistical analysis (t-test Microsoft Excel 2010), may contribute to the symetrical strengthening of upper limbs in 88%. We have discovered two types development phenomena - visualised as 2 distinct curves that show the development of strength in 30 seconds. Keywords: Children, indoor climbing, preference, handedness,...

No description available.

Šiandien dviratis užima gana svarbią vietą tarp kitų transporto rūšių. Jis suteikia didesnę judėjimo laisvę, todėl naudojamas laisvalaikio praleidimui, susisiekimui, turizmui, sportavimui. Tai ne tik patogi, bet ir ekonomiška važiavimo priemonė. Kadangi dviračio vairas yra vienas svarbiausių jo elementų, lemiančių dviračio valdymą, todėl svarbu kad vairo statinis stiprumas ir standumas atitiktų keliamus reikalavimus. Šių reikalavimų laikymasis turi įtakos dviračio kokybei ir saugumui. Atitikimas standartų normoms nustatomas atliekant bandymus. Bandymų rezultatai laikomi teigiamais, jeigu po atliktų tyrimų nenustatomi lūžiai, įtrūkimai, įbrėžimai ar leistinus dydžius viršijantys konstrukcijos formos pakitimai. Siekiant išanalizuoti ir eksperimentiškai patikrinti dviračio vairo statinį stiprumą ir standumą naudojant plėvelinius tenzojutiklius ir informacinę matavimo sistemą, valdomą „Catman“ programine įranga, buvo atliktas eksperimentinis dviračio vairo statinio stiprumo ir standumo tyrimas. Tiek eksperimentinio tyrimo rezultatai, tiek baigtinių elementų metodo skaičiavimai, parodė, kad dviračio vairas atitiko standartuose keliamus dviračio vairo standumo ir stiprumo reikalavimus ir neviršijo juose numatytų reikšmių. / Nowadays bike has quite an important place among other modes of transport. It provides greater freedom of movement, and it is used for leisure, travelling, tourism and sports. It is not only convenient but also cost-effective vehicle of travelling. As the bicycle wheel is one of its most important elements that determine the wheel control, so it is important that the static strength and rigidity would comply with the requirements of qualify. Quality requirements compliance has an impact on the quality and safety of the bicycle. Compliance to the requirements is determined during the experiment. The experiment is considered positive if there are no breaks, cracks, scratches and the structural changes in shape meet the permitted levels. In order to analyse and experimentally verify the handlebar static strength and rigidity using tenzosensor measurement and information system operated by „Catman” software has been made an experimental bicycle wheel strength and rigidity analysis. Experimental results and finite element method calculations showed that the bicycle wheel meets the strength and rigidity standards requirements and don’t exceed them.

Tikslas – nustatyti kineziterapijos poveikį slaugytojų, dirbančių slaugos skyriuje, juosmeninės stuburo dalies skausmui ir funkcijai. Tyrimo hipotezė – galvojame, kad naudojant juosmeninės stuburo dalies raumenis stiprinančius pratimus bei juosmens tempimą Saunders aparatu juosmeninės stuburo dalies skausmas mažės, o funkcija – gerės. Stuburo ligos yra labai paplitusios visame pasaulyje: apie 80 proc. pasaulio gyventojų bent kartą yra jautę vienokio ar kitokio intensyvumo nugaros skausmą. Apie 20 proc. gyventojų periodiškai pasikartoja nugaros skausmas, trunkantis tris ir daugiau dienų (Seibutis, 2008). Nugaros juosmeninės dalies skausmas yra labai paplitęs, dažniausiai jis nustatomas darbingo amžiaus žmonėms nuo 30 iki 50 metų amžiaus (Secer ir kt., 2009). Temos aktualumas – slaugos skyriuje dirbančiam personalui tenka susidurti su slaugos priemonių ir kėlimo įrangos stoka bei dideliu darbo krūviu, todėl personalas skundžasi varginančiais stuburo skausmais dėl netaisyklingo pacientų kėlimo ir vartymo (Aw et al., 2013). Užsienio autorių (d'Errico et al., 2013) atliktuose tyrimuose buvo nustatyta, kad dirbančių slaugytojų tarpe ypatingai dažnas yra juosmeninės stuburo dalies skausmas, kurį būtina kontroliuoti ir imtis priemonių nedarbingumui dėl jo mažinti. Temos naujumas – mokslinių tyrimų ir straipsnių apie slaugos skyriuje dirbančių slaugytojų nugaros juosmeninės dalies skausmus nėra daug. Kadangi slaugos skyriuose dirbančių slaugytojų darbo sąlygoms ir tenkančiam krūviui... [toliau žr. visą tekstą] / Object: to determine the effects of physical therapy for nurses working in the nursing section of the lumbar spine pain and function. Hypothesis of research – we think that the use of lumbar spine exercises and lumbar strain Saunders apparatus lumbar spine pain will decrease and the function is going to get better. Spinal diseases are very common in all world: about 80 percent of world population at least once felt one or another back pain intensity. About 20 percent of population back pain, lasting for three or more days is periodically recurring (Seibutis, 2008). Low back pain is a very common disorder, but mostly is determinated for able – bodied persons aged from 30 till 50 years old (Secer et al., 2009). Relevance of the subject – in the care unit working staff have to deal with the lack of nursing tools and lifting equipment and a heavy workload, because staff complaining to of troublesome of low back pain about incorrect patient lifting and turning (Aw et al., 2013). Previous investigations of foreign authors, it was found that nurses working in particular among frequent is pain in the lumbar spine, which it is necessary to monitor the occurrence of and to take measures for its reduction (d'Errico et al., 2013). Newness of the subject – research and articles about nursing for nurses working in the section of the back lumbar pain is not a lot of. Whereas the sections working in nursing nurses working conditions and the lack of attention given to the workload, decreasing... [to full text]

This master thesis deals with calculation of steel wire ropes for cranes. Concretely is acted about calculation of wire ropes overhead crane manufactured by KRÁLOVOPOLSKÁ a.s. designed for load capacities up to 25 000 kg, which is situated at hall of steelworks. Further, the calculation of wire ropes different overhead crane was made to compare the results. The solution includes calculation made using valid standards ČSN 27 0100, DIN 15020-1, FEM 1.001 and ČSN EN 13001-3-2. Finally, the procedures are evaluated and compared with each other.