<p>About ten years ago Volvo Cars could see that car manufactures began to introduce rear wheel arch liners made of non-woven fabrics or some kind of laminate which are mostly common today. Volvo Cars have also seen that competitors now are beginning to develop the front wheel arch liners more and more and expect a development equal to the one for the rear wheel arch liners. This is why we are set to optimize the front wheel arch liner.</p><p>For development of mechanical products such as car parts, a discursive method is most suitable to follow. For example systematical concept development which we have used in our work.</p><p>From a technical point of view, our results shows that the penta laminate used for the wheel arch liner on Mercedes Benz S-class is by far the best material. Unfortunately it is rather expensive which of course affects its result in a negative way when cost is taken in to consideration. When including cost, the solid plastic is actually rather economical.</p><p>After assessment of the result in total we are however convinced that Volvo Cars should concentrate on further research of penta laminate and open negotiations with different suppliers regarding a material of this kind.</p><p>Regarding the geometry, the tests and studies that Volvo Cars have performed earlier on splash shields clearly shows the usage of the part and further research done by our selves does not point at any problems with a splash shield integrated in the wheel arch liner.</p> / <p>För ungefär tio år sedan kunde Volvo Cars se att biltillverkare började introducera bakre hjulhus tillverkade av ”non-woven” fibrer eller någon form av laminat vilket idag är högst vanligt. Volvo Cars har också sett att konkurrenter nu börjar utveckla främre hjulhus mer och mer och räknar med en utveckling liknande den för bakre hjulhus. Detta är anledningen till att vi har fått uppgiften att optimera det främre hjulhuset.</p><p>För utveckling av mekaniska produkter så som bildelar, är en diskursiv metod mest lämpad att följa. Till exempel systematisk konceptutveckling som vi har valt att använda i vårt arbete.</p><p>Sett ur ett tekniskt perspektiv, visar våra resultat att pentalaminatet som används för hjulhusen på Mercedes Benz S-klass, är det överlägset bästa materialet. Tyvärr ar det ganska dyrt vilket naturligtvis påverkar dess resultat negativt när hänsyn tas till kostnader. När vi även ser till kostnaderna, är faktiskt den rena plasten mycket ekonomisk. Efter bedömning av det totala resultatet, är vi helt övertygade om att Volvo Cars borde koncentrera sig på fortsatta undersökningar av pentalaminat och inleda förhandlingar med olika underleverantörer angående material av denna typ.</p><p>Angående geometrin, visar Volvo Cars’ sedan tidigare genomförda tester och studier att en splash shield fyller en viktig funktion och vidare undersökningar genomförda av oss själva pekar inte på några problem med en i hjulhuset integrerad splash shield.</p>

Solid-state amorphous materials show amazing promise in thin-film electronics. The interface-to-bulk ratio of thin films makes interfacial chemistries of these systems of utmost importance. Thin films of amorphous metals, dielectrics and semiconductors have novel chemistries that are not only based upon their elemental constituent makeup, but also based upon the method with which the amorphous material is deposited and treated after deposition. The chemical attributes unique to amorphous, thin-film systems are defined primarily through the utilization of solution-processed aluminum oxide phosphate dielectric material and Zr������Cu������Al������Ni������ metal. the chemical findings wrought via the observation of interactions between amorphous metal-dielectric systems are applied to semiconductor/insulator systems to illustrate the use of the same general chemical principles applying to diverse problems. Finally in the appendices, the systems are utilized to create extremely-thin tunneling electronic devices and optical metamaterials as well as innovative classroom material. / Graduation date: 2012 / Access restricted to the OSU Community at author's request from Dec. 13, 2011 - Dec. 13, 2012

The eight-node solid-shell finite element models have been developed for the analysis of laminated composite pate/shell structures with piezoelectric actuators and sensors. To resolve the locking problems of the solid-shell elements in laminated materials and improve accuracy, the assumed natural strain method and hybrid stress method are employed. The nonlinear electric potential distribution in piezoelectric layer is described by introducing internal electric potential. The developed finite element models, especially, electric potential node model, have the advantages of simpler modeling and can obtain same effect that exact solution described. / Singapore-MIT Alliance (SMA)

Advanced composites are playing a rapidly increasing role in all fields of material and structural related engineering practices. Damage tolerance analysis must be a critical integral part of composite structural design. The predictive capabilities of existing models have met with limited success because they typically can not account for multiple damage evolution and their coupling. As a result, current composite design is heavily dependent upon lengthy and costly test programs and empirical design methods. There is an urgent need for efficient numerical tools that are capable of analyzing the progressive failure caused by nonlinearly coupled, multiple damage evolution in composite materials. Such numerical tools are a necessity in achieving virtual testing of composites and other heterogeneous materials. In this thesis, an advanced finite element method named augmented finite element method (A-FEM) has been developed. This method is capable of incorporating nonlinear cohesive damage descriptions for major damage modes observed in composite materials. It also allows for arbitrary nucleation and propagation of such cohesive damages upon satisfactory of prescribed initiation and propagation criterion. Major advantages of the A-FEM include: 1) arbitrary cohesive cracking without the need of remeshing; 2) full compatibility with existing FEM packages; and 3) easy inclusion of intra-element material heterogeneity. The numerical capabilities of the A-FEM have been demonstrated through direct comparisons between prediction results and experimental observations of typical composite tests including 3-point bending of unidirectional laminates, open-hole tension of quasi-isotropic laminates, and double-notched tension of orthogonal laminates. In all these tests, A-FEM can predict not only the qualitative damage patterns but also quantitatively the nonlinear stress-strain curves and other history-dependent results. The excellent numerical capability of A-FEM in accurately accounting for multiple cracking in composites enables the use of A-FEM as a multi-scale numerical platform for virtual testing of composites. This has been demonstrated by a series of representative volume element (RVE) analyses which explicitly considered microscopic matrix cracking and fiber matrix interface debonding. In these cases the A-FEM successfully predicted the cohesive failure descriptions which can be used for macroscopic composite failure analyses. At the sublaminate scale, the problem of a transverse tunneling crack and its induced local delamination has been studied in detail. Two major coupling modes, which depends on the mode-I to mode-II fracture toughness ratio and cohesive strength values, has been revealed and their implications in composite engineering has been fully discussed. Finally, future improvements to the A-FEM so that it can be more powerful in serving as a numerical platform for virtual testing of composites are discussed.

Several problems must be solved in the construction, design, and operation of a nuclear fusion reactor. One of the chief problems in the manufacture of high-powered copper/polymer composite magnets is the difficulty to precisely control the fiber volume fraction. In this thesis, the effect of variations in fiber volume fraction on thermal stresses in copper/cyanate ester composite cylinders is investigated. The cylinder is a composite that uses copper wires that run longitudinally in a cyanate ester resin specifically developed by Composite Technology Development, Inc. This composite cylinder design is commonly used in magnets for nuclear fusion reactors. The application of this research is for magnets that use cylindrical coil geometry such as the Mega Amp Spherical Tokamak (MAST) in the UK. However, most stellarator magnet designs use complex geometries including the National Compact Stellarator Experiment (NCSX), and the Quasi-Poloidal Stellarator (QPS). Even though the actual stresses calculated for the cylindrical geometry may not be directly applicable to these projects, the relationship between fiber volume fraction and stresses will be useful for any geometry. The effect of fiber volume fraction on stresses produced by mechanical, thermal and magnetic loads on cylindrical magnet coils is studied using micromechanics with laminate plate theory (LPT) and finite element analysis (FEA). Based on the findings of this research, variations in volume fraction do significantly affect the stress experienced by the composite cylinder. Over a range of volume fractions from 0.3 to 0.5, the LPT results demonstrate that thermally induced stresses vary approximately 30% while stresses due to pressure vary negligibly. The FEA shows that magnetic stresses vary much less at around only 5%. FEA results seem to confirm the LPT model. It was also concluded that the stress in the insulation layers due to all types of loadings is significant and must be considered when using this system in fusion applications.

The introduction of carbon-fibre reinforced plastics in loadbearing automotive structures provides a great potential toreduce vehicle weight and fuel consumption. To enable themanufacture and assembly of composite structural parts,reliable and cost-effective joining technologies must bedeveloped. This thesis addresses several aspects of joining andload introduction in carbon-fibre reinforced plastics based onnon-crimp fabric reinforcement. The bearing strength of carbon fibre/epoxy laminates wasinvestigated considering the effects of bolt-hole clearance.The laminate failure modes and ultimate bearing strength werefound to be significantly dependent upon the laminate stackingsequence, geometry and lateral clamping load. Significantreduction in bearing strength at 4% hole deformation was foundfor both pin-loaded and clamped laminates. The ultimatestrength of the joints was found to be independent of theinitial bolt-hole clearance. The behaviour of hybrid (bolted/bonded) joints wasinvestigated both numerically and experimentally. Athree-dimensional non-linear finite element model was developedto predict the load transfer distribution in the joints. Theeffect of the joint geometry and adhesive material propertieson the load transfer was determined through a parameter study.An experimental investigation was undertaken to determine thestrength, failure mechanisms and fatigue life of hybrid joints.The joints were shown to have greater strength, stiffness andfatigue life in comparison to adhesive bonded joints. However,the benefits were only observed in joint designs which allowedfor load sharing between the adhesive and the bolt. The effect of the environment on the durability of bondedand hybrid joints was investigated. The strength and fatiguelife of the joints was found to decrease significantly withincreased ageing time. Hybrid joints demonstrated increasedfatigue life in comparison to adhesive bonded joints afterageing in a cyclic freeze/thaw environment. The strength and failure mechanisms of composite laminatessubject to localised transverse loading were investigatedconsidering the effect of the specimen size, stacking sequenceand material system. Damage was found to initiate in thelaminates at low load levels, typically 20-30% of the ultimatefailure load. The dominant initial failure mode wasintralaminar shear failure, which occurred in sub-surfaceplies. Two different macromechanical failure modes wereidentified, fastener pull-through failure and global collapseof the laminate. The damage patterns and ultimate failure modewere found to depend upon the laminate stacking sequence andresin system. Finite element analysis was used to analyse thestress distribution within the laminates and predict first-plyfailure. Keywords:Composite, laminate, bearing strength,joining, load introduction, hybrid joint, finite elementanalysis, mechanical testing.

About ten years ago Volvo Cars could see that car manufactures began to introduce rear wheel arch liners made of non-woven fabrics or some kind of laminate which are mostly common today. Volvo Cars have also seen that competitors now are beginning to develop the front wheel arch liners more and more and expect a development equal to the one for the rear wheel arch liners. This is why we are set to optimize the front wheel arch liner. For development of mechanical products such as car parts, a discursive method is most suitable to follow. For example systematical concept development which we have used in our work. From a technical point of view, our results shows that the penta laminate used for the wheel arch liner on Mercedes Benz S-class is by far the best material. Unfortunately it is rather expensive which of course affects its result in a negative way when cost is taken in to consideration. When including cost, the solid plastic is actually rather economical. After assessment of the result in total we are however convinced that Volvo Cars should concentrate on further research of penta laminate and open negotiations with different suppliers regarding a material of this kind. Regarding the geometry, the tests and studies that Volvo Cars have performed earlier on splash shields clearly shows the usage of the part and further research done by our selves does not point at any problems with a splash shield integrated in the wheel arch liner. / För ungefär tio år sedan kunde Volvo Cars se att biltillverkare började introducera bakre hjulhus tillverkade av ”non-woven” fibrer eller någon form av laminat vilket idag är högst vanligt. Volvo Cars har också sett att konkurrenter nu börjar utveckla främre hjulhus mer och mer och räknar med en utveckling liknande den för bakre hjulhus. Detta är anledningen till att vi har fått uppgiften att optimera det främre hjulhuset. För utveckling av mekaniska produkter så som bildelar, är en diskursiv metod mest lämpad att följa. Till exempel systematisk konceptutveckling som vi har valt att använda i vårt arbete. Sett ur ett tekniskt perspektiv, visar våra resultat att pentalaminatet som används för hjulhusen på Mercedes Benz S-klass, är det överlägset bästa materialet. Tyvärr ar det ganska dyrt vilket naturligtvis påverkar dess resultat negativt när hänsyn tas till kostnader. När vi även ser till kostnaderna, är faktiskt den rena plasten mycket ekonomisk. Efter bedömning av det totala resultatet, är vi helt övertygade om att Volvo Cars borde koncentrera sig på fortsatta undersökningar av pentalaminat och inleda förhandlingar med olika underleverantörer angående material av denna typ. Angående geometrin, visar Volvo Cars’ sedan tidigare genomförda tester och studier att en splash shield fyller en viktig funktion och vidare undersökningar genomförda av oss själva pekar inte på några problem med en i hjulhuset integrerad splash shield.

This study aimed to develop a biofilter packed only with fern chips for the removal of air-borne low concentration VOCs (volatile organic compounds) emitted from various industries such as semiconductor manufacturing and electronic ones. The fern chip biofilters could avoid the shortcomings of traditional media, such as compaction, drying, and breakdown, which lead to the performance failure of the biofilters. The study contains two topics. The first is a performance test on the elimination of mixed VOCs used in semiconductor manufacturing industries in an air stream. The second is the one on the elimination of a single VOC (methyl ethyl ketone) in a waste gas drawn from a CCL (copper clad laminate) plant. Two pilot-scale biofilters consisted of two columns (0.40 mW¡Ñ0.40 mL¡Ñ0.70 mH acrylic column) arranged in series were used for the performance tests. Each of the two columns was packed with fern chips to a packing volume of around 56 L (0.40 mW¡Ñ0.40 mL¡Ñ0.35 mH). A sprinkler was set over the packed fern chips for providing them with water and nutrition solutions. Liquid leached from both layers of chips were collected in the bottom container of the column. In the first topic, tests were performed for biofiltration removal of VOCs in simulated semiconductor manufacturing emitted gases which consisted of IPA (isopropyl alcohol), acetone, HMDS (hexamethylene disilazane), PGME (propylene glycol monomethyl ether), and PGMEA (propylene glycol monomethyl ether acetate). From the results, it could be proposed that for achieving over 94% of the VOC removal, appropriate operation conditions are media moisture content = 52-68%, media pH = 7-8, influent VOC concentration = 150-450 mg/Am3, empty bed residence time (EBRT) = 0.75 min, and volumetric organic loading L to the whole media = 11.4-34.1 g/m3.h. In the second topic, performances of biofiltration for the removal of methyl ethyl ketone (MEK) in a gas stream from a copper clad laminate (CCL) manufacturing process were tested. Experimental results indicate that with L of <115 g /m3.h., EBRT = 0.5-1.28 min , media pH = 5.3-6.8, influent MEK concentration = 215-1,670 mg/Am3, MEK removal efficiencies of over 91% were obtained. Instant milk powder was essential to the good and stable performance of the biofilter for MEK removal.

The thesis aims to investigate the mechanical behavior and properties of a centrally notched hybrid Magnesium/Carbon-Fiber/PEEK laminate at elevated temperature. The high performance hybrid composite laminates of 0.5mm Magnesium sheets sandwiched by Carbon-Fiber/PEEK (APC-2) guasi-isotropic and cross-ply laminates were fabricated. The Magnesium sheets were polished and cleaned by acetone, then underwent the surface treatment by CrO3-base solvent etchants, cured by the improved diaphragm curing process. The finished laminates were cut into the specimen than drilled a 4mm diameter hole in the center of specimen. At first, the ultimate strength, stiffness and stress-strain diagram were obtained due to static tension tests at elevated temperature, such as 25¢XC(RT), 75¢XC, 100¢XC, 125¢XC, and 150¢XC. Compare of them, the notched quasi-isotropic ones drop almost 50% in strength, and the notched cross-ply ones are half of unnotched ones. The two lay-up notched specimens are slightly below the unnotched ones in stiffness. The strength of the specimens are decrease as temperature rise. As the temperature rise the stiffness of quasi-isotropic ones drop, but it just change little in cross-ply ones. Then the notched specimen fatigue life and load-cycle (P-N) curves were obtained by tension-tension fatigue test. The P-N curves were adopt to prevent the stress concretion of the notched specimen. Consider the same loading, notched specimens has worse fatigue behavior, but in the same load ratio, the normalized P-N curves of the unnotched ones were below the notched ones means notched ones has better fatigue behavior. Recording the specimen image by video camera during the testing process, the cracks at the edge of hole were found. However delamination was not found. Necking was observed in quasi-isotropic specimens, but not in cross-ply. Observed by optical microscopy, the improved surface treatment will decrease the probability of delamination from 20% to less than 10% after hot press.

The aim of this thesis is to manufacture Ti/APC-2 hybrid composite laminates and obtain its mechanical properties and fatigue characteristics at elevated temperatures. Ti/APC-2 laminates were composed of two layers of APC-2 and three layers of titanium sheets. For superior bonding ability between titanium and APC-2, chromic anodic method was adopted to treat titanium sheets in manufacturing process and APC-2 was stacked according to cross-ply [0/90]s and quasi-isotropic [0/45/90/-45] sequences. Then, the modified curing process was adopted to fabricate Ti/APC-2 hybrid composite laminates. Tension and fatigue tests carried out with MTS 810 and MTS 651 environmental control chamber to lift and maintain experimental temperatures, such as 25¢XC, 75¢XC, 100¢XC, 125¢XC and 150¢XC. From static tensile tests, the mechanical properties of cross-ply and quasi-isotropic composite laminates, such as ultimate strength, longitudinal stiffness were gained and the stress-strain diagrams of laminates were also plotted from testing data at elevated temperature. From fatigue tests we obtained laminate¡¦s fatigue resistance properties and the experimental data of applied stress vs. cycles were plotted as S-N diagrams at elevated temperature. From the tensile and fatigue tests, the important remarks were summarized as follows. First, no matter what the APC-2 stacking sequence was, the ultimate strength and longitudinal stiffness decreased while temperature rising, especially at 150¢XC; second, a turning point appeared at each stress-strain diagram that kink angle caused the decrease of stiffness while temperature rising; third, combining fatigue data and stress-strain diagrams we analogized a presumption that the region before turning point was in elastic behavior and after turning point in plastic deformation; fourth, quasi-isotropic laminates had better fatigue resistance than that of cross-ply laminates; sixth, the longitudinal stiffness before turning point was in good agreement with the prediction by using the modified ROM, however, after turning point the errors became large.