820 resultados para thermoelastic deformation
Resumo:
Monitavoiteoptimointia käytetään laajasti auto- ja lentokoneteollisuudessa suunnittelun apu-välineenä, mutta muuten sen käyttö ei ole vielä yleistynyt laajemmin. Tässä työssä on tarkoi-tus tehdä laaja esiselvitys monitavoiteoptimoinnista ja sen hyödyntämisestä työkonepuomien suunnittelun apuvälineenä. Työ tehtiin yhteistyössä Lappeenrannan teknillisen yliopiston ja projektiin osallistuvien FIMA ry:n jäsenten kanssa. Tulosten ja johtopäätösten perusteella tutkimusta tullaan mahdollisesti jatkamaan Tampereen teknillisen yliopiston tohtorikoulussa. Työssä selvitettiin mitä monitavoiteoptimoinnilla tarkoitetaan ja esitellään sen etenemisvai-heet. Lisäksi työssä esitellään lyhyesti kuusi monitavoiteoptimointiohjelmistoa pääominai-suuksineen sekä selvitetään ohjelmistolisenssien hintoja. Työssä optimointiin perehdyttiin teleskooppipuomin jatkoksen case -tutkimuksen avulla. Ni-velpuomit ja nivel- ja teleskooppipuomien yhdistelmät rajattiin työn ulkopuolelle. Työssä muodostettiin teleskooppipuomin jatkoksen poikkileikkauksen optimointityökalu. Sen avulla voidaan laskea luotettavasti optimit mitat painon suhteen niin, että lommahdusrajoitteet, tai-vutusvastus sekä taipuma otetaan huomioon ja samalla voitiin arvioida optimointiprosessin etuja ja haittoja. Optimoinnin tuloksia voidaan käyttää edelleen monitavoiteoptimoinnin lähtö-arvoina. Optimointi tehtiin Matlabin avulla ja tulokset verifioitiin AGIFAP -elementtimenetelmäohjelmistolla. Optimoituja tuloksia tutkittiin edelleen Femap -elementtimenetelmäohjelmistolla, jolla haettiin vuorovaikutussuhteita monitavoiteoptimoinnin tueksi. FE -analyysien avulla muodostettiin kaksi apuohjelmaa optimoinnin tueksi. Työssä havaittiin, että teleskooppipuomin jatkoksen optimointi vaatii FE -analyysiohjelmiston rinnalleen, jotta voidaan varmistua rakenteen kestävyydestä ja optimoida väsymiskestävyyt-tä. Liukupalojen vaikutus teleskooppipuomin käytökseen sekä väsymiskestävyyden optimoin-ti vaatii jatkotutkimusta.
Resumo:
Rolling element bearings are essential components of rotating machinery. The spherical roller bearing (SRB) is one variant seeing increasing use, because it is self-aligning and can support high loads. It is becoming increasingly important to understand how the SRB responds dynamically under a variety of conditions. This doctoral dissertation introduces a computationally efficient, three-degree-of-freedom, SRB model that was developed to predict the transient dynamic behaviors of a rotor-SRB system. In the model, bearing forces and deflections were calculated as a function of contact deformation and bearing geometry parameters according to nonlinear Hertzian contact theory. The results reveal how some of the more important parameters; such as diametral clearance, the number of rollers, and osculation number; influence ultimate bearing performance. Distributed defects, such as the waviness of the inner and outer ring, and localized defects, such as inner and outer ring defects, are taken into consideration in the proposed model. Simulation results were verified with results obtained by applying the formula for the spherical roller bearing radial deflection and the commercial bearing analysis software. Following model verification, a numerical simulation was carried out successfully for a full rotor-bearing system to demonstrate the application of this newly developed SRB model in a typical real world analysis. Accuracy of the model was verified by comparing measured to predicted behaviors for equivalent systems.
Resumo:
Työssä on tutkittu laboratoriokokeen ja elementtimenetelmän avulla eri geometrioiden vaikutusta sekundääriseen momentin syntymiseen K-liitoksella. Kokeen liitos on tehty S700-lujuusluokan Ruukin Optim 700 plus MH nelikulmaisista rakenneputkista (RHS). Elementtimalleissa on käytetty geometrista ja materiaalista epälineaarisuutta ennustamaan liitoksen muodonmuutoskykyä ja laskennallista kestävyyttä. Liitoksen elementtimalleissa muutettavia geometrioita ovat: vapaaväli, uumasauvan ja paarteen välinen kulma, paarteen seinämän paksuus, liitoksen eksentrisyys ja uumasauvan ja paarteen leveyden suhde. Laboratoriokokeen liitoksen vetouumasauvassa vaikuttava sekundäärisen momentin aiheuttama jännitys on noin 25 % vetouumasauvan myötörajasta. Suurin sekundäärinen momentti syntyy, kun vapaaväliä pienennetään ja uumasauvaa kavennetaan paarteeseen nähden. Eurocode 3:n mitoitusohjeita voidaan elementtimallien perusteella soveltaa tietyille geometrioille turvallisesti.
Resumo:
The most common reason for a low-voltage induction motor breakdown is a bearing failure. Along with the increasing popularity of modern frequency converters, bearing failures have become the most important motor fault type. Conditions in which bearing currents are likely to occur are generated as a side effect of fast du/dt switching transients. Once present, different types of bearing currents can accelerate the mechanical wear of bearings by causing deformation of metal parts in the bearing and degradation of the lubricating oil properties.The bearing current phenomena are well known, and several bearing current measurement and mitigation methods have been proposed. Nevertheless, in order to develop more feasible methods to measure and mitigate bearing currents, better knowledge of the phenomena is required. When mechanical wear is caused by bearing currents, the resulting aging impact has to be monitored and dealt with. Moreover, because of the stepwise aging mechanism, periodically executed condition monitoring measurements have been found ineffective. Thus, there is a need for feasible bearing current measurement methods that can be applied in parallel with the normal operation of series production drive systems. In order to reach the objectives of feasibility and applicability, nonintrusive measurement methods are preferred. In this doctoral dissertation, the characteristics and conditions of bearings that are related to the occurrence of different kinds of bearing currents are studied. Further, the study introduces some nonintrusive radio-frequency-signal-based approaches to detect and measure parameters that are associated with the accelerated bearing wear caused by bearing currents.
Resumo:
The bedrock of old crystalline cratons is characteristically saturated with brittle structures formed during successive superimposed episodes of deformation and under varying stress regimes. As a result, the crust effectively deforms through the reactivation of pre-existing structures rather than by through the activation, or generation, of new ones, and is said to be in a state of 'structural maturity'. By combining data from Olkiluoto Island, southwestern Finland, which has been investigated as the potential site of a deep geological repository for high-level nuclear waste, with observations from southern Sweden, it can be concluded that the southern part of the Svecofennian shield had already attained structural maturity during the Mesoproterozoic era. This indicates that the phase of activation of the crust, i.e. the time interval during which new fractures were generated, was brief in comparison to the subsequent reactivation phase. Structural maturity of the bedrock was also attained relatively rapidly in Namaqualand, western South Africa, after the formation of first brittle structures during Neoproterozoic time. Subsequent brittle deformation in Namaqualand was controlled by the reactivation of pre-existing strike-slip faults.In such settings, seismic events are likely to occur through reactivation of pre-existing zones that are favourably oriented with respect to prevailing stresses. In Namaqualand, this is shown for present day seismicity by slip tendency analysis, and at Olkiluoto, for a Neoproterozoic earthquake reactivating a Mesoproterozoic fault. By combining detailed field observations with the results of paleostress inversions and relative and absolute time constraints, seven distinctm superimposed paleostress regimes have been recognized in the Olkiluoto region. From oldest to youngest these are: (1) NW-SE to NNW-SSE transpression, which prevailed soon after 1.75 Ga, when the crust had sufficiently cooled down to allow brittle deformation to occur. During this phase conjugate NNW-SSE and NE-SW striking strike-slip faults were active simultaneous with reactivation of SE-dipping low-angle shear zones and foliation planes. This was followed by (2) N-S to NE-SW transpression, which caused partial reactivation of structures formed in the first event; (3) NW-SE extension during the Gothian orogeny and at the time of rapakivi magmatism and intrusion of diabase dikes; (4) NE-SW transtension that occurred between 1.60 and 1.30 Ga and which also formed the NW-SE-trending Satakunta graben located some 20 km north of Olkiluoto. Greisen-type veins also formed during this phase. (5) NE-SW compression that postdates both the formation of the 1.56 Ga rapakivi granites and 1.27 Ga olivine diabases of the region; (6) E-W transpression during the early stages of the Mesoproterozoic Sveconorwegian orogeny and which also predated (7) almost coaxial E-W extension attributed to the collapse of the Sveconorwegian orogeny. The kinematic analysis of fracture systems in crystalline bedrock also provides a robust framework for evaluating fluid-rock interaction in the brittle regime; this is essential in assessment of bedrock integrity for numerous geo-engineering applications, including groundwater management, transient or permanent CO2 storage and site investigations for permanent waste disposal. Investigations at Olkiluoto revealed that fluid flow along fractures is coupled with low normal tractions due to in-situ stresses and thus deviates from the generally accepted critically stressed fracture concept, where fluid flow is concentrated on fractures on the verge of failure. The difference is linked to the shallow conditions of Olkiluoto - due to the low differential stresses inherent at shallow depths, fracture activation and fluid flow is controlled by dilation due to low normal tractions. At deeper settings, however, fluid flow is controlled by fracture criticality caused by large differential stress, which drives shear deformation instead of dilation.
Resumo:
The viscoelastic properties of edible films can provide information at the structural level of the biopolymers used. The objective of this work was to test three simple models of linear viscoelastic theory (Maxwell, Generalized Maxwell with two units in parallel, and Burgers) using the results of stress relaxation tests in edible films of myofibrillar proteins of Nile Tilapia. The films were elaborated according to a casting technique and pre-conditioned at 58% relative humidity and 22ºC for 4 days. The testing sample (15mm x 118mm) was submitted to tests of stress relaxation in an equipment of physical measurements, TA.XT2i. The deformation, imposed to the sample, was 1%, guaranteeing the permanency in the domain of the linear viscoelasticity. The models were fitted to experimental data (stress x time) by nonlinear regression. The Generalized Maxwell model with two units in parallel and the Burgers model represented the relaxation curves of stress satisfactorily. The viscoelastic properties varied in a way that they were less dependent on the thickness of the films.
Resumo:
Rheology is the science that studies the deformation and flow of solids and fluids under the influence of mechanical forces. The rheological measures of a product in the stage of manufacture can be useful in quality control. The microstructure of a product can also be correlated with its rheological behavior allowing for the development of new materials. Rheometry permits attainment of rheological equations applied in process engineering, particularly unit operations that involve heat and mass transfer. Consumer demands make it possible to obtain a product that complies with these requirements. Chocolate industries work with products in a liquid phase in conching, tempering, and also during pumping operations. A good design of each type of equipment is essential for optimum processing. In the design of every process, it is necessary to know the physical characteristics of the product. The rheological behavior of chocolate can help to know the characteristics of application of the product and its consumers. Foods are generally in a metastable state. Their texture depends on the structural changes that occur during processing. Molten chocolate is a suspension with properties that are strongly affected by particle characteristics including not only the dispersed particles but also the fat crystals formed during chocolate cooling and solidification. Chocolate rheology is extensively studied, and it is known that chocolate texture and stability is strongly affected by the presence of specific crystals
Resumo:
The hydration kinetics of transgenic corn types flint DKB 245PRO, semi-flint DKB 390PRO, and dent DKB 240PRO was studied at temperatures of 30, 40, 50, and 67 °C. The concentrated parameters model was used, and it fits the experimental data well for all three cultivars. The chemical composition of the corn kernels was also evaluated. The corn cultivar influenced the initial rate of absorption and the water equilibrium concentration, and the dent corn absorbed more water than the other cultivars at the four temperatures analyzed. The effect of hydration on the kernel texture was also studied, and it was observed that there was no significant difference in the deformation force required for all three corn types analyzed with longer hydration period.
Resumo:
The non-idealities in a rotor-bearing system may cause undesirable subcritical superharmonic resonances that occur when the rotating speed of the rotor is a fraction of the natural frequency of the system. These resonances arise partly from the non-idealities of the bearings. This study introduces a novel simulation approach that can be used to study the superharmonic vibrations of rotor-bearing systems. The superharmonic vibrations of complex rotor-bearing systems can be studied in an accurate manner by combining a detailed rotor and bearing model in a multibody simulation approach. The research looks at the theoretical background of multibody formulations that can be used in the dynamic analysis of flexible rotors. The multibody formulations currently in use are suitable for linear deformation analysis only. However, nonlinear formulation may arise in high-speed rotor dynamics applications due to the cenrrifugal stiffening effect. For this reason, finite element formulations that can describe nonlinear deformation are also introduced in this work. The description of the elastic forces in the absolute nodal coordinate formulation is studied and improved. A ball bearing model that includes localized and distributed defects is developed in this study. This bearing model could be used in rotor dynamics or multibody code as an interface elements between the rotor and the supporting structure. The model includes descriptions of the nonlinear Hertzian contact deformation and the elastohydrodynamic fluid film. The simulation approaches and models developed here are applied in the analysis of two example rotor-bearing systems. The first example is an electric motor supported by two ball bearings and the second is a roller test rig that consists of the tube roll of a paper machine supported by a hard-bearing-type balanceing machine. The simulation results are compared to the results available in literature as well as to those obtained by measuring the existing structure. In both practical examples, the comparison shows that the simulation model is capable of predicting the realistic responses of a rotor system. The simulation approaches developed in this work can be used in the analysis of the superharmonic vibrations of general rotor-bearing systems.
Resumo:
Strenx® 960 MC is a direct quenched type of Ultra High Strength Steel (UHSS) with low carbon content. Although this material combines high strength and good ductility, it is highly sensitive towards fabrication processes. The presence of stress concentration due to structural discontinuity or notch will highlight the role of these fabrication effects on the deformation capacity of the material. Due to this, a series of tensile tests are done on both pure base material (BM) and when it has been subjected to Heat Input (HI) and Cold Forming (CF). The surface of the material was dressed by laser beam with a certain speed to study the effect of HI while the CF is done by bending the specimen to a certain angle prior to tensile test. The generated results illustrate the impact of these processes on the deformation capacity of the material, specially, when the material has HI experience due to welding or similar processes. In order to compare the results with those of numerical simulation, LS-DYNA explicit commercial package has been utilized. The generated results show an acceptable agreement between experimental and numerical simulation outcomes.
Resumo:
Castor bean cropping has great social and economic value, but its production has been affected by factors such as low quality seeds used for sowing. The quick and precise evaluation of seed quality by x-ray test is known as an effective method to evaluate seed lots, but little is known about the interpretation between of the type of radiographic image and the seed quality correlation. The potential of x-ray analysis as a marker of seed physiological quality and as an initial process for the implementation of the use of computer-assisted image analysis was investigated using castor bean seeds of the different cultivars. The seeds were classified according to internal morphology visualized in the radiography and subjected to the germination test, emergency and seedling growth rate. It was possible to identify the different types of internal tissues, morphological and physical damage in castor bean seeds using the x-ray test. Tissues generating translucent images, embryo deformation, or tissues with less than 50% of endosperm reserves or spotted, negatively affected the physiological potential of the seed lots. Radiographic analysis is effective as an instrument to improve castor bean seed lot quality. This non destructive analysis allows the prediction of seedling performance and enabled the selection of high-quality seeds under the standards of a sustainable and precision agriculture
Resumo:
This dissertation describes an approach for developing a real-time simulation for working mobile vehicles based on multibody modeling. The use of multibody modeling allows comprehensive description of the constrained motion of the mechanical systems involved and permits real-time solving of the equations of motion. By carefully selecting the multibody formulation method to be used, it is possible to increase the accuracy of the multibody model while at the same time solving equations of motion in real-time. In this study, a multibody procedure based on semi-recursive and augmented Lagrangian methods for real-time dynamic simulation application is studied in detail. In the semirecursive approach, a velocity transformation matrix is introduced to describe the dependent coordinates into relative (joint) coordinates, which reduces the size of the generalized coordinates. The augmented Lagrangian method is based on usage of global coordinates and, in that method, constraints are accounted using an iterative process. A multibody system can be modelled as either rigid or flexible bodies. When using flexible bodies, the system can be described using a floating frame of reference formulation. In this method, the deformation mode needed can be obtained from the finite element model. As the finite element model typically involves large number of degrees of freedom, reduced number of deformation modes can be obtained by employing model order reduction method such as Guyan reduction, Craig-Bampton method and Krylov subspace as shown in this study The constrained motion of the working mobile vehicles is actuated by the force from the hydraulic actuator. In this study, the hydraulic system is modeled using lumped fluid theory, in which the hydraulic circuit is divided into volumes. In this approach, the pressure wave propagation in the hoses and pipes is neglected. The contact modeling is divided into two stages: contact detection and contact response. Contact detection determines when and where the contact occurs, and contact response provides the force acting at the collision point. The friction between tire and ground is modelled using the LuGre friction model, which describes the frictional force between two surfaces. Typically, the equations of motion are solved in the full matrices format, where the sparsity of the matrices is not considered. Increasing the number of bodies and constraint equations leads to the system matrices becoming large and sparse in structure. To increase the computational efficiency, a technique for solution of sparse matrices is proposed in this dissertation and its implementation demonstrated. To assess the computing efficiency, augmented Lagrangian and semi-recursive methods are implemented employing a sparse matrix technique. From the numerical example, the results show that the proposed approach is applicable and produced appropriate results within the real-time period.
Resumo:
Rocks correlated with the Hough Lake and Quirke Lake Groups of the Huronian Supergroup form part of a northeasterly trending corridor that separates 1750 Ma granitic intrusive rocks of the Chief Lake batholith from the 1850 Ma mafic intrusive rocks of the Sudbury Igneous Complex. This corridor is dissected by two major structural features; the Murray Fault Zone (MFZ) and the Long Lake Fault (LLF). Detailed structural mapping and microstructural analysis indicates that the LLF, which has juxtaposed Huronian rocks of different deformation style and metamorphism grade, was a more significant plane of dislocation than the MFZ. The sense of displacement along the LLF is high angle reverse in which rocks to the southeast have been raised relative to those in the northwest. South of the LLF Huronian rocks underwent ductile defonnation at amphibolite facies conditions. The strain was constrictional, defined by a triaxial strain ellipsoid in which X > Y > z. Calculations of a regional k value were approximately 1.3. Penetrative ductile defonnation resulted in the development of a preferred crystallographic orientation in quartz as well as the elongation of quartz grains to fonn a regional southeast-northwest trending, subvertical lineation. Similar lithologies north of the LLF underwent dominantly brittle deformation under greenschist facies conditions. Deformation north of the LLF is characterized by the thrusting of structural blocks to form angular discordances in bedding orientation which were previously interpreted as folds. Ductile deformation occurred between 1750 and 1238 Ma and is correlated with a regional period of south over north reverse faulting that effected much of the southern Sudbury region. Post dating the reverse faulting event was a period of sedimentation as a conglomerate unit was deposited on vertically bedded Huronian rocks. Rocks in the study area were intruded by both mafic and felsic dykes. The 1238 Ma mafic dykes appear to have been offset during a period of dextral strike slip displacement along the major fault'). Indirect evidence indicates that this event occurred after the thrusting at 950 to 1100 Ma associated with the Grenvillian Orogeny.
Resumo:
The study area is situated in NE Newfoundland between Gander Lake and the north coast and on the boundary between the Gander and Botwood tectonostratigraphic zones (Williams et al., 1974). The area is underlain by three NE trending units; the Gander Group, the Gander River Ultramafic Belt (the GRUB) and the Davidsville Group. The easternmost Gander Group consists of a thick, psammitic unit composed predominantly of psammitic schist and a thinner, mixed unit of semipelitic and pelitic schist with minor psammite. The mixed unit may stratigraphically overlie the psammitic unit or be a lateral facies equivalent of the latter. No fossils have been recovered from the Gander Group. The GRUB is a terrain of mafic and ultramafic plutonic rocks with minor pillow lava and plagiogranite. It is interpreted to be a dismembered ophiolite in thrust contact with the Gander Group. The westernmost Davidsville Group consists of a basal conglomerate, believed deposited unconformably upon the GRUB from which it was derived, and an upper unit of greywacke and slate, mostly of turbidite origin, with minor limestone and calcareous sandstone. The limestone, which lies near the base of the unit, contains Upper Llanvirn to Lower Llandeilo fossils. The Gander and Davidsville Groups display distinctly different sedimentological , structural and metamorphic histories. The Gander Group consists of quartz-rich, relatively mature sediment. It has suffered three pre-Llanvirn deformations, of which the main deformation, Dp produced a major, NE-N-facing recumbent anticline in the southern part of the study area. Middle greenschist conditions existed from D^ to D- with growth of metamorphic minerals during each dynamic and static phase. In contrast, the mineralogically immature Davidsville Group sediment contains abundant mafic and ultramafic detritus which is absent from the Gander Group. The Davidsville Group displays the effects of a single penetrative deformation with localized D_ and D_ features, all of which can be shown to postdate D_ in the Gander Group. Rotation of the flat Gander S- into a subvertical orientation near the contact with the GRUB and the Davidsville Group is believed to be a Davidsville D^ feature. Regional metamorphism in the Davidsville Group is lower greenschist with a single growth phase, MS . These sedimentological, structural and metamorphic differences between the Gander and Davidsville Groups persist even where the GRUB is absent and the two units are in contact, indicating that the tectonic histories of the Gander and Davidsville Groups are distinctly different. Structural features in the GRUB, locally the result of multiple deformations, may be the result of Gander and/or Davidsville deformations. Metamorphism is in the greenschist facies. Geochemical analyses of the pillow lava suggest that these rocks were formed in a back-arc basin. Mafic intrusives in the Gander Group appear to be the result of magraatism separate from that producing the pillow lava. The Gander Group is interpreted to be a continental rise prism deposited on the eastern margin of the Late Precambrian-Lower Paleozoic lapetus Ocean. The GRUB, oceanic crust possibly formed in a marginal basin to the west, is believed to have been thrust eastward over the Gander Group, deforming the latter, during the pre-Llanvirnian, possibly Precambrian, Ganderian Orogeny. The Middle Ordovician and younger Davidsville Group was derived from, and deposited unconformably on, this deformed terrain. Deformation of the Davidsville Group occurred during the Middle Devonian Acadian Orogeny.
Resumo:
The Horwood Peninsula - Gander Bay area is located at NE Newfoundland in the Botwood Zone (Williams et a1., 1974) or in the Dunnage Zone (Williams, 1979) of the Central Mobile Belt of the Newfoundland Appalachians. The area is underlain by Middle Ordovician to possible Lower Silurian rocks of the Davidsville and Indian Islands Groups, respectively. Three conformable formations named informally : the Mafic Volcanic Formation, the Greywacke and Siltstone Formation and the Black Slate Formation, have been recognized in the Davidsville Group. The Greywacke and the Black Slate Formations pass locally into a Melange Formation. From consideration of regional structure and abundant locally-derived mafic volcanic olisto- 1iths in the melange, it is considered to have originated by gravity sliding rather than thrusting. Four formations have been recognized in the Indian Islands Group. They mainly contain silty slate and phyllite, grey cherty siltstone, green to red micaceous siltstone and limestone horizons. Repetition of lithological units by F1 folding are well-demonstrated in one of formations in this Group. The major structure in this Group on the Horwood Peninsula is interpreted to be a synclinal complex. The lithology of this Group is different from the Botwood Group to the west and is probably Late Ordovician and/or Early Silurian in age. The effects of soft-sediment deformation can be seen from the lower part of the Davidsville Group to the middle part of the Indian Islands Group indicating continuous and/or episodic slumping and sliding activities throughout the whole area. However, no siginificant depOSitional and tectonic break that could be assigned to the Taconian Orogeny has been recognized in this study. Three periods of tectonic deformation were produced by the Acadian Orogeny. Double boudinage in thin dikes indicates a southeast-northwest sub-horizontal compression and main northeast-southwest sub-horizontal extension during the D1 deformation. A penetrative, axial planar slaty cleavage (Sl) and tight to isocJ.ina1 F1 folds are products of this deformation. The D2 and D3 deformations formed S2 and S3 fabrics associated with crenulations and kink bands which are well-shown in the slates and phyllites of the Indian Islands Group. The D2 and D3 deformations are the products of vertical and northeast-southwest horizontal shortening respectively. The inferred fault between the Ordovician slates (Davidsville Group) and the siltstones (Indian Islands Group) suggested by Williams (1963, 1964b, 1972, 1978) is absent. Formations can be followed without displacement across this inferred fault. Chemically, the pillow lavas, mafic agglomerates, tuff beds and diabase dikes are subdivided into three rock suites : (a) basaltic komatiite (Beaver Cove Assemblage), (b) tholeiitic basalt (diabase dikes), (c) alkaline basalt (Shoal Bay Assemblage). The high Ti02 , MgO, Ni contents and bimodal characteristic of the basaltic komatiite in the area are comparable to the Svartenhuk Peninsula at Baffin Bay and are interpreted to be the result of an abortive volcano-tectonic rift-zone in a rear-arc basin. Modal and chemical analyses of greywackes and siltstones show the trend of maturity of these rocks increasing from poorly sorted Ordovician greywackes to fairly well-sorted Silurian siltstones. Rock fragments in greywackes indicate source areas consisting of plagiogranite, low grade metamorphic rocks and ultramafic rocks. Rare sedimentary structures in both Groups indicate a southeasterly provenance. Trace element analyses of greywackes also reveal a possible island-arc affinity.