This dissertation addresses the problem of motion planning and control for nonholonomic mobile robots, particularly wheeled and tracked mobile robots, working in extreme environments, for example, desert, forest, and mine. In such environments, the mobile robots are highly subject to external disturbances (e.g., slippery terrain, dusty air, etc.), which essentially introduce uncertainties to the robot systems. The complexity of the motion planning problem is due to taking both nonholonomic and uncertainty constraints into account simultaneously. As a result, none of the conventional nonholonomic motion planning can be directly applied. The control problem is even more challenging since state constraints posed by obstacles in the environments must also be considered along with the nonholonomic and uncertainty constraints. In this research, we systematically develop a new type of motion planning technique that determines an optimal path for a mobile robot in a given environment. This motion planning technique is based on the idea of a maximum allowable uncertainty, which is a number assigned to each free configuration in the environment. The optimal path is a path connecting given initial and goal configurations through a series of configurations respecting the nonholonomic constraint and possessing the highest maximum allowable uncertainty. Both linear and quadratic approximations of the maximum allowable uncertainty, including their corresponding motion planners, have been studied. Additionally, we develop the first real-time robust control algorithm for the mobile robot under uncertainty to follow given paths safely and accurately in cluttered environments. The control algorithm also utilizes the concept of the maximum allowable uncertainty as well as the robust control theory. The simulation results have shown the effectiveness and robustness of the control algorithm in steering the mobile robot along a given path amidst obstacles without collisions even when the level of robot uncertainty is high. / Ph. D.

<p><strong>ABSTRACT</strong></p><p>D Level Essay in Political Science, Autumn Semester 2008 by Mattias Andersson. Tutor: Alf Sundin. “The Swedish Centre Party and Nuclear Power. A Study of Change in a Political Party”</p><p>The aim of this essay is to examine the policy of the Swedish Centre Party on nuclear power. More exactly the aim is to study if the Centre Party has been going through a change of policy on nuclear power and, if so, how the policy has changed. The essay is about the Centre Party, the Centre Party’s Youth League and the Centre Party’s Women’s Association. The Student Association as well as different special interests in trade and industry with a connection to the Centre Movement have been delimited. The time periods studied are 1979-1988 and 2001-2008. The analysis of the ideology is based on Herbert Tingsten. The various arguments are presented in tables. A couple of concepts from Gunnar Sjöblom have also been used. These are the research questions:</p><p>- Has the Centre Party changed its ideology on nuclear power?</p><p>- Has the Centre Party changed its arguments on nuclear power?</p><p>- Has the Centre Party’s Youth League changed its policy and its arguments on nuclear power?</p><p>- Has the Centre Party’s Women’s Association changed its policy and its arguments on nuclear power?</p><p>- Have the prospects of success for the Centre Party’s policy on nuclear power changed:a, in the electoral arena?b, in the parliamentary arena?c, in the internal arena?</p><p>The research has been made from political and environmental programs as well as some newspaper articles and interviews. Motions on nuclear power to the Centre Party’s assembly have also been studied. The essay makes it plain that the Centre Party has changed its ideology on nuclear power. The fundamental values have changed as well as the recommended action. The main arguments are still the same and have not changed, however a few of the arguments from the earlier time period are no longer used. The Centre Party’s Youth League has been going through the biggest change and is today even in favour of uranium mining in Sweden whereas the Centre Party’s Women’s Association has changed from a strong commitment into a lack of a policy on their own. Earlier there was a strong sense of consensus in the Centre Movement. Today there are all kinds of views on nuclear power within the movement. The policy of today has good prospects of success in the parliament and among voters but is problematic within the party.</p><p>Remaining research fields are to further examine the internal opinions on nuclear power, especially within the Youth League and the Women’s Association. Another field is to study whether the change has been influenced by special interests in trade and industry. A further examination of the concept of change would also be clarifying. </p> / <p><strong>SAMMANDRAG</strong></p><p>D-uppsats av Mattias Andersson, Statsvetenskap IV, ht 2008. Handledare: Alf Sundin ”Centerpartiet och kärnkraften. En studie av förändring i ett parti”</p><p>Syftet är att undersöka om Centerpartiet har förändrat sin politik i kärnkraftsfrågan samt hur politiken i kärnkraftsfrågan i så fall har förändrats. I uppsatsen studeras Centerpartiet, Centerpartiets ungdomsförbund och Centerkvinnorna, medan Centerstudenter eller särintressen med speciell anknytning till Centerrörelsen avgränsats. Två tidsperioder studeras, perioden 1979-1988 samt 2001-2008. I ideologianalysen har Herbert Tingstens syn på ideologibegreppet tillämpats. Argumentationsanalysen redovisas i form av tabeller där de förekommande argumenten för och mot kärnkraft vid de undersökta tidpunkterna redovisas. En analys-modell av Gunnar Sjöblom har också använts. Syftet preciseras till följande forskningsfrågor:</p><p>- Har Centerpartiet förändrat sin ideologi i kärnkraftsfrågan?</p><p>- Har Centerpartiet förändrat sina argument i kärnkraftsfrågan?</p><p>- Har Centerpartiets ungdomsförbund förändrat sin politik respektive sina argument i kärnkraftsfrågan?</p><p>- Har Centerkvinnorna förändrat sin politik respektive sina argument i kärnkraftsfrågan?</p><p>- Har utsikterna till framgång för Centerpartiets politik i kärnkraftsfrågan förändrats:a, på väljararenan?b, på den parlamentariska arenan?c, på den interna arenan?</p><p>I huvudsak har parti- och miljöprogram och motioner till riksstämman studerats, men även några tidningsartiklar och intervjuer har använts. Studien visar att Centerpartiet har förändrat sin ideologi i kärnkraftsfrågan på flera olika sätt. Grundvärderingarna har förändrats, liksom handlingsrekommendationerna. Centerpartiet fortsätter däremot att argumentera mot kärnkraften såsom tidigare; dock har några argument som tidigare användes försvunnit. Centerpartiets ungdomsförbund har gjort den radikalaste omsvängningen i kärnkraftsfrågan och är numera även för uranbrytning i Sverige, medan Centerkvinnorna gått från att vara starkt engagerade till att inte längre föra en egen politik i kärnkraftsfrågan. Tidigare rådde en tydlig konsensus inom centerrörelsen; idag finns olika åsikter om kärnkraft företrädda. Den politik som förts under senare år har goda utsikter till parlamentarisk och väljarmässig framgång men är internt problematisk.</p><p>Kvarvarande frågor är att närmare undersöka den interna situationen i Centerpartiet, inte minst i ungdomsförbundet och kvinnoförbundet. Man skulle också kunna undersöka LRF eller andra näringslivsintressen och studera i vilken mån de har utövat inflytande över den här förändringen. Det kvarstår också att fördjupa litteraturanknytningen kring begreppet förändring.</p>

Cette thèse traite des problèmes des concentrations de contraintes locales, en particularité des effets des bords libres dans des structures stratifiés. À l'interface entre deux couches avec des propriétés élastiques différentes, les contraintes ont un comportement singulier dans le voisinage du bord libre en supposant un comportement de matériau élastique linéaire. Par conséquent, ils sont essentiels pour promouvoir le délaminage. Via Formulation unifiée de la Carrera (CUF) différents modèles cinématiques sont testés dans le but de capter les concentrations de contraintes. Dans la première partie de ce travail, les approches de modélisation dimensionnelle réduits sont comparées. Deux classe principale sont présentés: la couche équivalent (ESL) et l'approche par couche, LW. Par la suite leurs capacités à capter les singularités sont comparées. En utilisant une fonction a priori singulière, via une expression exponentielle, une mesure des contraintes singulières est introduite. Seulement deux paramètres décrivent pleinement les composantes des contraintes singulières au voisinage du bord libre. Sur la base des paramètres obtenus les modèles sont comparés et aussi les effets sous des charges d'extension et de flexion et pour différents stratifiés. Les résultats montrent une nécessité des modèles complexes dans le voisinage du bord libre. Cependant loin des bords libres, dans le centre de plaques composite, aucune différence significative ne peut être noté pour les modèles plutôt simples. La deuxième partie de ce travail est donc dédiée au couplage de modèles cinématique incompatibles. Modèles complexes et coûteux sont utilisés seulement dans des domaines locaux d'intérêt, tandis que les modèles économiques simples seront modéliser le domaine global. La eXtended Variational Formulation (XVF) est utilisé pour coupler les modèles de dimensionnalité homogènes mais de cinématique hétérogènes. Ici pas de recouvrement de domaine est présent. En outre, le XVF offre la possibilité d'adapter les conditions imposées à l'interface en utilisant un paramètre scalaire unique. On montre que, pour le problème de dimensionnalité homogène, que deux conditions différentes peuvent être imposées par ce paramètre. Un correspondant à des conditions fortes des Multi Point Constraints (MPC) et un second fournir des conditions faibles. La dernière offre la possibilité de réduire extrêmement le domaine qui utilise le modèle cinématique complexe, sans perte de précision locale. Comme il s'agit de la première application de la XVF vers les structures composites, le besoin d'un nouvel opérateur de couplage a été identifié. Un nouveau formulaire est proposé, testé et sa robustesse sera évaluée. / This work considers local stress concentrations, especially the free-Edge effects of multilayered structures. At the interface of two adjacent layers with different elastic properties, the stresses can become singular in the intermediate vicinity of the free edge. This is valid while assuming a linear elastic material behaviour. As a consequence this zones are an essential delamination trigger. Via the Carrera Unified Formulation (CUF), different kinematical models are testes in order to obtain the correct local stress concentration. In the first part of this work, the reduced dimensional modelling approaches are compared. Two main class are presented: Equivalent Single Layer (ESL) models treating the layered structure like one homogenous plate of equal mechanical proper- ties, and the Layer Wise approach, treating each layer independently. Subsequently their capabilities to capture the appearing singularities are compared. In order to have a comparable measurement of those singularities, the obtained stress distributions will be expressed via a power law function, which has a priori a singular behaviour. Only two parameters fully describe therefore the singular stress components in the vicinity of the free edge. With the help of these two parameters not only the different models capabilities will be compared, but also the free edge effect itself will be measured and compared for different symmetrical laminates and the case of extensional and uniform bending load. The results for all laminates under both load cases confirm the before stated need for rather complex models in the vicinity of the free edge. However far from the free edges, in the composite plates centre, no significant difference can be noted for rather simple models. The second part of this work is therefore dedicated to the coupling of kinematically incompatible models. The use of costly expensive complex models is restricted to local domains of interest, while economic simple models will model the global do- main. The Extended Variational Formulation (XVF) is identified as the most suitable way to couple the kinematically heterogenous but dimensional homogenous models. As it uses a configuration with one common interface without domain overlap, the additional efforts for establishing the coupling are limited. Further the XVF offers the possibility to adapt the conditions imposed at the interface using a single scalar parameter. It will be shown that for the homogenous dimensional problem under consideration only two different conditions can be imposed by this parameter. One matching the strong conditions imposed by the classical Multi Point Constrains (MPC) and a second one providing a weak condition. The last one is shown to provide the possibility to reduce further the domain using the complex kinematical model, without the loss of local precision. As this is the first application of the XVF towards composite structures, the need for a new coupling operator was identified. A new form is proposed, tested and its robustness will be evaluated.

The aim of this paper is to ascertain what kind of feminist expressions that are prevalent in two of Sweden’s major political youth organizations, the Swedish Social Democratic Youth League and the Centre Party Youth using ideal types constructed from major feminist ideologies. A comparison between the two is also a part of the analysis, to clarify the differences and similarities between the two regarding issues pertaining gender equality. Socialist feminism and radical feminism were prevalent in the Swedish Social Democratic Youth League but it also contained expressions of liberal feminism. The Centre Party Youth were exclusively liberal feminist in their expression. The differences between the two were ideological and the causal explanations for why gender equality exists differed as well. The similarities were limited to certain specific issues where they identified similar, if not identical, problems in society.

Dans le domaine de l’aéronautique, l’acception ‘shape morphing’ a été utilisée pour identifier ces avions qui subissent certaine modifications géométrique pour améliorer leur adaptation au différents profils de missions. Différemment de la solution classique, celle ‘shape morphing’ exige : une distribution d’actionnement avec une densité de puissance élevée, une mécanisation des structures, des revêtements souples, et le développement des loi de contrôle. Dans ce scénario, un modèle capable reconnaitre l'insertion de capteur et d'actionneur de nouvelle génération, et capable de réduire au minimum le coût du calcul devient très intéressant. Ce travail essaye d'affronter deux aspects différents du problème. Dans la première partie, la question suivante a été exploitée: pour un problème donné, géométrie, chargement, etc. .. condition aux limites, quel est le modèle le plus précis en terme de résultats, fidélité et avec le plus réduit coût de calcul? Deux approches différentes ont été utilisées pour donner une réponse. Le diagramme de la « Théorie Meilleur Plate (RTPB) » a été dessiné. Avec cet instrument il est possible, pour un problème donné, d'identifier les modèles ayants les meilleurs temps de calcul et une bonne fidélité des résultats. Dans la deuxième partie de la thèse un modèle avancé mono dimensionnel et multi domaine en éléments fini est présenté. Le modèle est capable de capturer l'insertion d'éléments piézo-électriques dans l'aile composite. Il a été développé à partir de la formulation Carrera unifiée et à partir de l'équation de comportement électro-mécanique. Une comparaison avec la bibliographie actuelle a été fait afin de valider les résultats. / In the field of aeronautics, shape morphing has been used to identify those aircraft that un-dergo certain geometrical changes to enhance or adapt to their mission profile. Different formthe classical solution the shape morphing required: distributed high-power density actuation, structural mechanization, flexible skins, and control law development. In these scenario, model able to capture the insertion of new generation sensor and actuator, and able to minimize the computational cost become very interesting. These work try to affront two different aspect of the problem. In the first part the following question has been exploited: for a given problem, geometry, loading, boundary condition etc... which is the most accurate model in term of results fidelity with the lowest computational cost? Two different approaches have been used to give an answer. The Best Plate Theory Diagram (BPTD) has been drawn. Trough the BPTD it is possible, for a given problem, to identify those models with the lowest computational time and a good results fidelity. An advanced mono-dimensional multi-field FEM model is presented in the second part of the thesis. The model is able to capture the insertion of piezo-electric elements in composite wing. It has been developed starting from the Carrera Unified Formulation and from the electro-mechanical constitutive equation. Comparison with the bibliography have be done in order to validate the results. / Nel campo dell’aeronautica il termine shape morphing identifica quei velivoli in grado di apportare determinati cambiamenti geometrici al fine di adattarsi a diversi profili di missione. Diversamente dalle soluzioni convenzionali la progettazione di velivoli shape morphing richiede : un’attuazione distribuita, uno skin flessibile in grado di pemettere le deformazioni e delle leggi di controllo. Divengono quindi di notevole interesse modelli in grado di cogliere l’inserzione di attuatori e sensori di nuova generazione all’interno dell’ala, e di esibire al contempo un basto costo computazionale. Nel lavoro presentato in questa tesi vengono trattati entrabi gli aspetti. Nella prima parte si è andati a dare una risposta alla segunete domanda: per un dato problema, geometria, condizioni di carico, etc..., qual è il modello più accurato, in termini di fedeltà dei risultati, che presenta il minor costo computazionale? Il problema è stato affrontato attraverso due differenti approcci, che hanno portato alla creazione della "Best Plate Theory Curve", attraverso la quale è possibile, per un dato problema, identificare il modello più idoneo in termini di fedeltà dei risultati e di costo computazionale. Nella seconda parte del lavoro viene presentato un modello mono-dimensionale multi-campo avanzato in grado di cogliere l’inserzione di elementi piezo-elettrici in ali in materiale composito. Questo elemento è stato viluppato partendo dalla Carrera Unified Formulation e dalle equazioni costitutive elettromeccaniche. Sono state effettuate poi delle validazioni attraverso confronti con la bibliografia.

ABSTRACT D Level Essay in Political Science, Autumn Semester 2008 by Mattias Andersson. Tutor: Alf Sundin. “The Swedish Centre Party and Nuclear Power. A Study of Change in a Political Party” The aim of this essay is to examine the policy of the Swedish Centre Party on nuclear power. More exactly the aim is to study if the Centre Party has been going through a change of policy on nuclear power and, if so, how the policy has changed. The essay is about the Centre Party, the Centre Party’s Youth League and the Centre Party’s Women’s Association. The Student Association as well as different special interests in trade and industry with a connection to the Centre Movement have been delimited. The time periods studied are 1979-1988 and 2001-2008. The analysis of the ideology is based on Herbert Tingsten. The various arguments are presented in tables. A couple of concepts from Gunnar Sjöblom have also been used. These are the research questions: - Has the Centre Party changed its ideology on nuclear power? - Has the Centre Party changed its arguments on nuclear power? - Has the Centre Party’s Youth League changed its policy and its arguments on nuclear power? - Has the Centre Party’s Women’s Association changed its policy and its arguments on nuclear power? - Have the prospects of success for the Centre Party’s policy on nuclear power changed:a, in the electoral arena?b, in the parliamentary arena?c, in the internal arena? The research has been made from political and environmental programs as well as some newspaper articles and interviews. Motions on nuclear power to the Centre Party’s assembly have also been studied. The essay makes it plain that the Centre Party has changed its ideology on nuclear power. The fundamental values have changed as well as the recommended action. The main arguments are still the same and have not changed, however a few of the arguments from the earlier time period are no longer used. The Centre Party’s Youth League has been going through the biggest change and is today even in favour of uranium mining in Sweden whereas the Centre Party’s Women’s Association has changed from a strong commitment into a lack of a policy on their own. Earlier there was a strong sense of consensus in the Centre Movement. Today there are all kinds of views on nuclear power within the movement. The policy of today has good prospects of success in the parliament and among voters but is problematic within the party. Remaining research fields are to further examine the internal opinions on nuclear power, especially within the Youth League and the Women’s Association. Another field is to study whether the change has been influenced by special interests in trade and industry. A further examination of the concept of change would also be clarifying. / SAMMANDRAG D-uppsats av Mattias Andersson, Statsvetenskap IV, ht 2008. Handledare: Alf Sundin ”Centerpartiet och kärnkraften. En studie av förändring i ett parti” Syftet är att undersöka om Centerpartiet har förändrat sin politik i kärnkraftsfrågan samt hur politiken i kärnkraftsfrågan i så fall har förändrats. I uppsatsen studeras Centerpartiet, Centerpartiets ungdomsförbund och Centerkvinnorna, medan Centerstudenter eller särintressen med speciell anknytning till Centerrörelsen avgränsats. Två tidsperioder studeras, perioden 1979-1988 samt 2001-2008. I ideologianalysen har Herbert Tingstens syn på ideologibegreppet tillämpats. Argumentationsanalysen redovisas i form av tabeller där de förekommande argumenten för och mot kärnkraft vid de undersökta tidpunkterna redovisas. En analys-modell av Gunnar Sjöblom har också använts. Syftet preciseras till följande forskningsfrågor: - Har Centerpartiet förändrat sin ideologi i kärnkraftsfrågan? - Har Centerpartiet förändrat sina argument i kärnkraftsfrågan? - Har Centerpartiets ungdomsförbund förändrat sin politik respektive sina argument i kärnkraftsfrågan? - Har Centerkvinnorna förändrat sin politik respektive sina argument i kärnkraftsfrågan? - Har utsikterna till framgång för Centerpartiets politik i kärnkraftsfrågan förändrats:a, på väljararenan?b, på den parlamentariska arenan?c, på den interna arenan? I huvudsak har parti- och miljöprogram och motioner till riksstämman studerats, men även några tidningsartiklar och intervjuer har använts. Studien visar att Centerpartiet har förändrat sin ideologi i kärnkraftsfrågan på flera olika sätt. Grundvärderingarna har förändrats, liksom handlingsrekommendationerna. Centerpartiet fortsätter däremot att argumentera mot kärnkraften såsom tidigare; dock har några argument som tidigare användes försvunnit. Centerpartiets ungdomsförbund har gjort den radikalaste omsvängningen i kärnkraftsfrågan och är numera även för uranbrytning i Sverige, medan Centerkvinnorna gått från att vara starkt engagerade till att inte längre föra en egen politik i kärnkraftsfrågan. Tidigare rådde en tydlig konsensus inom centerrörelsen; idag finns olika åsikter om kärnkraft företrädda. Den politik som förts under senare år har goda utsikter till parlamentarisk och väljarmässig framgång men är internt problematisk. Kvarvarande frågor är att närmare undersöka den interna situationen i Centerpartiet, inte minst i ungdomsförbundet och kvinnoförbundet. Man skulle också kunna undersöka LRF eller andra näringslivsintressen och studera i vilken mån de har utövat inflytande över den här förändringen. Det kvarstår också att fördjupa litteraturanknytningen kring begreppet förändring.

2014 är det supervalår i Sverige. Det innebär intensiv marknadsföring för de olika politiska intressena i många olika kanaler. För många, men kanske speciellt för unga människor, kan detta bli en förvirrande period av budskap och åsikter som på olika sätt ska värderas och tas ställning till. De politiska ungdomsförbunden riktar sig till personer mellan sex och 25 år, och hör för det mesta till ett så kallat moderparti, men har egna politiska agendor, grafiska profiler och marknadsföring. Den mesta av marknadsföringen sker genom någon slags grafiskt material, och för att de politiska budskapen verkligen ska nå fram till alla unga på bästa sätt, borde det grafiska materialet också rent visuellt tala för innehållet. Den här studien syftar till att undersöka om det finns samband mellan politik och grafiska profiler hos de politiska ungdomsförbunden. Då studier på sambandet mellan politik och grafiskt material visat sig vara ett relativt outforskat område som det är svårt att hitta exakt data om, är detta en kvalitativ tvärsnittsstudie. Tio politiska ungdomsförbund valdes ut för granskning med grund i moderpartiernas storlek i riksdagsvalet 2010. Vidare samlades data om dessa in genom kvalitativa dokument och audiovisuella kanaler, vilket exempelvis innefattar de politiska ungdomsförbundens grafiska manualer och webbsidor. Studien visar på samband mellan politiken och de grafiska profilernas. Dessa uppstod mellan förbunden som ingår i blockpolitiken, men även mellan förbund på skilda delar av skalan som hade andra aspekter än blockpolitik gemensamt.

Composite laminated structures are prone to delamination. Rotorcraft flexbeams, apart from many other aerospace primary load carrying members are made up of composite laminated structures. A delaminated primary load carrying member can lead to catastrophic failure of the system of which it is a part. Delamination modeling and detection in composite laminated structures are challenging areas of ongoing research worldwide. Existing literature falls short of addressing effects of widthwise partial delamination on the modal characteristics of beams. To address this issue, a new partial delamination model for composite beams is proposed and implemented using the finite element method. Homogenized cross-sectional stiffness of the delaminated beam is obtained by the proposed analytical technique, including extension-bending, extension-twist and torsion-bending coupling terms, and hence can be used with an existing finite element method. A two-noded C1-type Timoshenko beam element with four degrees of freedom per node for dynamic analysis of beams is implemented. The results for different delamination scenarios and beams subjected to different boundary conditions are validated with available experimental results in the literature and/or with a 3-D finite element simulation using COMSOL. Results of the first torsional mode frequency for the partially delaminated beam are validated with the COMSOL results. The key point of the current work is that even partial delamination in long structures can be analyzed using a 1-D beam model, rather than using computationally more demanding 3-D or 2-D models. Rotor craft flexbeams are prone to delaminations, which in most realistic situations are partial along both the length and the width. However, the effect of partial delamination on the modal characteristics of the beam is not studied by researchers to the best of the author’s knowledge. Addressing this issue, a rotorcraft flexbeam is analysed here in the presence of delamination. A set of nonlinear governing equations for the rotating flexbeam are developed in hybrid basis. The flexbeam model developed has axial stretch, transverse displacement and flexural rotation in flapwise direction and twist as its degrees of freedom. The nonlinear governing differential equations are linearised and solved for eigenvalues and eigenvectors using a finite element method. The effects of angular speed and delamination size and location on the flexbeam modes are analysed. The results obtained using the proposed model are validated with the COMSOL 3-D finite element simulations. Next, the issue of delamination detection in beams is addressed. Mode shape curvature and Katz fractal dimension are used to detect the presence of partial delaminations in a beam. The effects of boundary conditions and location of delamination on the fractal dimension curve are studied. Usage of higher mode shape data for detection of delamination in beams is evaluated. Limitations of the Katz fractal dimension curve for delamination detection are enumerated. It is shown that fractal dimension measure and mode shape curvature can be used to detect the presence of partial delamination in beams. It is found that the torsional mode shape is best suited for partial delamination detection in beams. Apart from beams, Shell-and plate-like structures are also extensively used in aerospace structures. The modeling of multilayered plates is introduced herein with the intention to model delaminations in 2D. Carrera Unified Formulation(CUF)plate model, developed using variational formulations, is used to derive the stiffness matrices and to apply, the Principle of Virtual Displacement(PVD) and the Reissner Mixed Variational Theorem (RMVT). It is known that FEM implementation for plates leads to the phenomenon of numerical locking: the so-called membrane and shear locking effects. A well-known remedy for addressing locking is the use of the Mixed Interpolated Tensorial Components(MITC) technique. A strategy similar to MITC approach in the RMVT formulation is used to construct an advanced locking-free finite element to treat the multilayered plates. Composite laminated plates are prone to delamination. Implementation of delamination in the CUF frame work using nine-noded quadrilateral MITC9 elements is discussed. MITC9 elements are devoid of shear locking and membrane locking. Delaminated structures, as well as the corresponding healthy structures, are analysed for free vibration modes. The results from the present work are compared with those from available experimental or/and theoretical research articles or/and the 3-D finite element simulations. The effects of different kinds and different percentages of interfacial area of delaminations on the first three natural frequencies of the structure are discussed. The presence of the open-mode or breathing mode delamination mode shape for large delaminations within the first three natural frequencies is discussed. Also, the switching of the places between the second bending mode and the first torsional mode frequencies is discussed. Results obtained from different ordered theories are compared in the presence of delamination. Advantage of layer wise theory as compared to equivalent single layer theories for very large delaminations is stated. The effects of different kinds of delamination and its effect on the second bending and first torsional mode shapes are discussed.