Polymer components are used in many different applications, including in industries where critical applications put high requirements regarding quality assessment. Such applications might include medical or food where the presence of discontinuities might induce bacterial growth or other unpleasantries, thus certain manufacturers must be able to maintain a zero-tolerance towards damaged components. This leads to the need for efficient testing methods of nondestructive nature capable of testing large quantities of components in a production line environment. The authors have been tasked by Acoustic Agree AB and Trelleborg AB, a world-leading producer of polymer engineered solutions, to find a nondestructive testing method capable of detecting discontinuities in thin polymer components in a production line environment. Implementation in production line environments puts requirements on test cycle time and a goal is to complete a test cycle within 3-4 seconds. Due to restrictions regarding available equipment and expertise, the focus has been put on applying nonlinear acoustic methods for nondestructive testing instead of more conventional methods. These methods utilize the nonlinear distortion of acoustic waves which causes certain characteristics to appear, such as the generation of Higher Harmonics (HH), frequency modulation (NWMS), resonance frequency shift (NRUS), and amplitude recovery (IDAR). Visual testing was used to discern visibly damaged samples from seemingly undamaged ones. The only methods which showed the possibility of discerning damaged thin polymer components were NRUS and IDAR. Only the latter has the capability to maintain the prescribed test cycle time. Nonlinear acoustic methods seem to be capable of detecting discontinuities in thin polymer components within the given time frame. More work is required to properly investigate the performance of NWMS and IDAR. The configuration used in this work was mainly focused on IDAR, resulting in specific calibration for NWMS was neglected. The sample population was also too low to collect sufficient data to ensure statistical certainty regarding the performance for either method. / Polymerkomponenter används i många olika tillämpningar, i synnerhet i industrier där kritiska tillämpningar ställer höga krav på kvalitetsbedömning. Sådana tillämpningar kan finnas inom medicinska- eller livsmedelsindustrier där förekomsten av diskontinuiteter kan inducera bakterietillväxt eller andra obehagliga egenskaper, därför måste vissa tillverkare upprätta nolltolerans mot skadade komponenter. Detta leder till behovet av effektiva provningsmetoder av oförstörande natur som kan utvärdera stora mängder komponenter i en produktionslinjemiljö. Författarna har fått uppdrag av Acoustic Agree AB och Trelleborg AB, en världsledande producent av polymertekniska lösningar, för att finna en oförstörande provningsmetod som kan detektera diskontinuiteter i tunna polymerkomponenter i en produktionslinjemiljö. Implementering i produktionslinjemiljöer ställer krav på testcykeltid och ett mål är att kunna slutföra en testcykel inom 3-4 sekunder. Begränsningen av tillgänglig utrustning och expertis har lett till att författarna har fokuserat på att tillämpa olinjära akustiska metoder för oförstörande provning istället för mer konventionella metoder. Dessa metoder utnyttjar olinjär distortion av akustiska vågor vilket medför att vissa egenskaper uppträder, såsom generering av övertoner (HH), frekvensmodulering (NWMS), resonansfrekvensskift (NRUS) och amplitudåtergång (IDAR). Visuell provning användes för att skildra synligt skadade prover från till synes oskadade. De enda metoder som visade möjligheten att urskilja skadade tunna polymerkomponenter var NRUS och IDAR. Endast den sistnämnda har förmågan att utföra provning inom den föreskrivna provcykeltiden. Olinjära akustiska metoder verkar kunna detektera diskontinuiteter i tunna polymerkomponenter inom den givna tidsramen. Mer arbete krävs för att korrekt utvärdera prestandan av NWMS och IDAR. Konfigurationen som användes i detta arbete var huvudsakligen inriktad på IDAR, vilket resulterade i att specifik kalibrering för NWMS ej utförts. Provpopulationen var även för låg för att kunna samla in tillräckligt med data för att uppnå statistisk säkerhet angående metodernas prestanda.

Induction hardening is a complex process that requires regular verification of the case depth and the microstructure. Today this verification is done by destructive testing where a cross section is analysed. The case depth is measured by several Vickers hardness impressions and the microstructure is analysed by a light optic microscope. This master thesis was performed in collaboration with Volvo GTO in Skövde, with the target to find out if an ultrasonic backscattering method is usable for analysing the case depths on induction hardened crankshafts. This was done by verifying the results provided by ultrasonic testing with the results provided by destructive testing. The measurements were done on several crankshafts with different case depths and steel composition. The result, for crankshafts with normal case depths, shows a good correlation between the destructive testing (DT) and the ultrasonic testing (UT). The mean value for the discrepancy was 0.39 mm with a standard deviation of 0.20 mm. The reproducibility of the method has a standard deviation of 0.074 mm.

The aerospace industry is constantly striving to becoming more economical and environmentally friendly. One of many efforts to achieve this is the Lightcam project which in this case is evaluating the use of additive manufacturing in the form of electron beam melting in conjunction with the nickel-based superalloy, Alloy 718. This combination is not fully explored and examined. For this purpose, a demonstrator vane was produced and it was subsequently evaluated in this thesis. The evaluation was performed in as-built condition and was divided in non-destructive testing, evaluation of these methods and metallographic review to confirm the results, and potentially revealing more properties. The non-destructive testing was performed using conventional radiography and computed tomography. Both methods struggled to deliver complete and reliable results, for varying reasons. Radiography could deliver results of the whole vane, but these were impossible to evaluate due to the rough surface created by the electron beam melting process. The computed tomography on the other hand was not affected by the rough surface and produced usable, though not complete, results of the vane. The reason for the computed tomography’s inability to deliver complete results was the material, varying thickness and complex geometry of the vane. As a complement and to verify the results from the non-destructive testing, a metallographic examination was conducted. These tests were conducted with the aim of answering the following three questions:  What non-destructive testing methods are suitable to evaluate Alloy 718 components manufactured with electron beam melting? - Neither radiography nor computed tomography are suitable as a sole evaluation method, for various reasons. All surface dependent methods were deemed unsuitable without testing due to the rough surface. What types of defects and in what quantity can they be found in the produced vane? - Defects found are: Porosity and lack of fusion, both found as internal and partially external and in varying sizes. Where are the defects located? - Pores are mainly found in the center of sections modeled to a 3mm thickness. Lack of fusion was found between build layers in all thicknesses. Apart from these results, hardness was found to vary depending on build height, increasing from the bottom towards the top. Microstructure was also found to vary with the build height, but always consisting of either equiaxed or columnar grains. / Lightcam

I detta examinationsarbetesrapport för högskoleingenjörsexamen inom Elektronik, presenteras en utredning för att svara på vad som skulle vara den mest generiska pulsgeneratorn för ultraljudstestning inom det klassiska intervallet 0.5 till 15 MHz. Det presenteras flera variabler i teorin, som påverkar en testsignal och varför det inte går att beräkna vad en generisk pulsgenerator bör åstadkomma. Denna rapport presenterar vilka pulsgeneratorer det finns och vad de mer högpresterande pulsgeneratorerna beskrivna i vetenskapliga forskningsresultat har presterat. Samt vilka tekniker som finns och varför vissa tekniker inte är lämpliga. Vid slutet av denna examinationsarbetesrapport presenteras, med hjälp av några antaganden om vad en generisk pulsgenerator behöver prestera, dras en slutsats om vilken av de föreslagna pulsgeneratorerna som är mest generisk. / This bachelor thesis, is a trial in answering what would be a generic pulse generator for ultrasonic testing in the classic test range of 0.5 to 15 MHz. It also goes through multiple variables that affects a test signal and why it really isn't possible to precalculate what a generical pulse generators should achive, in the theory chapter. This thesis also goes through what different types of pulse generators there is and what some of the more high performance pulse generators proposed in scientific articles have achieved and what techniques that have been used and why some techniques are not suitable. In the end of this thesis there is a trial with some assumptions about what a generical pulse generator should achieve, to come to a conclusion about which pulse generator from the proposed ones would be the best generical pulse generator to go with.

CE-märkta stålbalkar byggdes in i två konstruktioner innan det upptäcktes att det fanns porer i hattbalkarnas svets. Den defekta svetsen innebar att byggnadernas bärförmåga inte kunde garanteras. Kunskapen kring inbyggt stål stommaterial med defekt svets är liten. Det är dessutom svårt att reparera och undersöka stålbalkarnas svets när de är inbyggda i konstruktionen. Syftet med examensarbetet är att hitta förstärkningsmetoder och därmed främja kortare hanteringstid vid händelse av att defekta stålbalkar byggs in i en konstruktion. Metoden består av litteraturstudie och intervjuer. Först granskas litteratur för att förstå problematiken med defekt svets i stål stommaterial. Därefter utförs intervjuer med personer erfarna inom stål och byggteknik. Examensarbetets resultat är ett flertal förstärkningsmetoder för inbyggda stålbalkar med defekt svets. Några av förstärkningsmetoderna är möjliga att utföra med den kunskap som finns idag medan andra behöver undersökas och värderas innan de kan implementeras. Förstärkningsmetoderna som är möjliga att utföra med dagens kunskap är: att svetsa om balken från insidan eller att placera en balk/fackverksbalk under den befintliga balken. De metoder som behöver undersökas och värderas vidare är: skruvförband genom balken, efterspänna balken med vajrar eller GWS-stag och sedan fylla den med betong, föra in en balk inne i balken och fylla balken med betong och att kolfiberförstärka svetsen. Slutsatsen är att den här studien kan ligga till grund för framtagning av åtgärder för inbyggda stålbalkar med defekt svets med mål att uppnå den dimensionerade hållfastheten och en lösning som är tidseffektiv, kostnadseffektiv och har låg klimatpåverkan. / Before the discovery of pores in the weld, CE-certified steel beams were embedded in two constructions. Since the weld was defective, the carrying capacity of the two buildings was questioned. There is a lack of knowledge about embedded steel beams with a damaged weld. It is difficult to repair and analyze the weld when the beams are embedded in the construction. The aim of the study is to find reinforcement methods for steel beams. The expectation is to shorten time in the production in case that defective steel beams are detected in the construction. The method consists of a literature study complemented by interviews. Literature is examined to understand the problem of defective welding in the steel framework. Subsequently, interviews are conducted with professionals within steel and building technology. The result of the report is multiple reinforcement methods for embedded steel beams with a defective weld. Some of the methods are possible to implement with the knowledge available today. Other methods need to be examined and assessed before executed. The reinforcement methods that are possible to perform are: weld the beam from the inside or place a beam underneath the existing beam. The methods that need further analysis are: drill a screw joint through the beam, strain the beam with steel-wires and fill the inside with concrete, place a beam inside the existing beam and fill the inside with concrete and last to reinforce the weld with carbon fibers. The conclusion is that this study can be used when reinforcement methods are needed for embedded steel beams with a defective weld. The objective with these methods is to restore the load-bearing capacity as well as finding a solution that is time efficient, economic and has low climatic influence.