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The suspensory apparatus of the distal phalanx (SADP) is an intricate adaptation of dermal and epidermal tissue that has a specialized role in the horse to absorb concussion while suspending the weight of the horse from within the hoof. The integrity of the hoof-bone connection is critical to the health of the horse and it can be affected by numerous disorders that cause it to fail. Accurate data on the ultimate tensile strength and other material properties of the SADP are important in modeling the behavior of the tissue under load and selecting appropriate prevention and treatment strategies for disorders of the SADP. The tensile load orientation and tissue sample size both have a profound effect on obtaining representative estimates for the material properties of a tissue. Consideration of the collagen fiber axis is important when selecting both. The purposes of this investigation were 1) to morphometrically determine the true collagen fiber axis in the SADP, 2) determine the most appropriate test sample size and tensile load orientation for materials testing, 3) to determine the ultimate tensile strength and other material properties of the SADP in healthy digits of adult horses, 4) to determine the site of tissue failure during testing, and 5) to determine whether freezing the SADP tissue samples prior to testing alters the material properties. Results of this investigation indicated that the true collagen fiber axis of the SADP in the toe region was predominantly vertical, in alignment with gravity. A vertical tensile load most closely matched the collagen fiber axis and was appropriate to model the load in the SADP for standing horses. A radial tensile load was appropriate to model the load in the SADP near the break over portion of the stride. Tissue blocks with a proximal-to-distal dimension of 1 cm tested less than 30% of the vertically oriented collagen fibers during radial tension testing and significantly underrepresented the ultimate tensile strength. The tissue failed in the deep dermis during radial tension testing and at the dermo epidermal junction during vertical tension testing. Freezing the tissue prior to testing significantly reduced the ultimate tensile strength.

<p> Thick turbidite beds, belonging to the β1 member, Cloridorme Formation (Ordovician), are exposed on the wavecut platform between St. H‎élier and Fame Point, Gasp‎é, Quebec. The local paleocurrent direction (to the west) is approximately parallel to the east-west strike of the vertical beds.</p> <p> These thick turbidite beds display a sequence of sedimentary structures which differs from the sequence defined by Bouma. Three broad divisions are recognised: a basal division consists of either limestone or quartz granule to pebble conglomerate (0-4 cms thick) or coarse sand greywacke or calcareous wacke (0-15 cms thick). Basal divisions of calcareous wacke frequently display ripple-lamination, parallel lamination, or upstream inclined laminae. Where the upstream inclined laminae form a single set, they occur below a sinuous profile (wavelength 40-80 cms, and amplitude 2-5 cms).</p> <p> A second division (0-330 cms thick) consists in most places of spindle or globular shaped calcareous nodules scattered in an argillaceous matrix. In some beds streaking and lobing of light coloured carbonate bearing material is associated with these nodules. The upper division consists of fine grained siltstone and shale.</p> <p> Thick broken blocks which have fallen from the cliffs, display the internal characteristics of the second division. Hemi-ellipsoid structures, arranged en echelon and convex towards the base of the bed, are displayed by one block.</p> <p> The upstream inclined laminae in the basal divisions of calcareous wacke beds are interpreted as the result of the upstream migration of antidunes. The nodules within the second division developed as 'pseudonodules'. The hemi-ellipsoid structures resemble damped large scale (macroturbulent) eddies associated with the flow of dense grain dispersions. The directions of the internal motions are shown by the orientation of grains and graptolite stipes.</p> <p> Correlation of these beds has been achieved over a distance of 7-1/2 miles. Over this distance the beds show little change in their characteristics. Basal divisions of granule and pebble conglomerate persist over this distance and show that coarse particles may be transported by turbidity currents over long distances. The sedimentary structures of the basal divisions of several calcareous wacke beds give the appearance (probably misleading) of an increase in flow regime downcurrent.</p> <p> The beds were probably deposited from initially low concentration but high density turbidity currents accompanied by a period of coarse grain traction and suspension near to the bed. In the case of calcareous wacke beds this period of traction formed rippled, flat or antidune bed forms. Stratification has been preserved by the rapid deposition of sediment en masse from the subsequent high concentration body of the current. The formation of a succession of 'quick' beds led to the sedimentation of the second division.</p> <p> Calculations suggest that the currents moved over slopes of much less than 1°.</p> / Thesis / Master of Science (MSc)

Annually and subannually laminated lacustrine sediments potentially contain a wide range of information that can be interpreted for paleoenvironmental reconstructions. These laminae are produced by the physical and biological processes that operate in the lake and in the surrounding terrestrial environment. However, identification of the influences that control laminae production may not be straightforward, and other processes may subtly influence the overall depositional sequence. This thesis examines two different depositional environments on Colin Archer Peninsula, Devon Island, Canada, with the objective of identifying the factors that influence subannual sediment deposition and how the resultant sedimentary structures can be used as indicators of paleoenvironmental conditions. In proglacial Lake R, clastic sediment deposition is controlled primarily by subannual meteorological conditions. Periods of positive air temperature or large rainfall events produce discernable laminae that, when combined, form a varve sequence. However, overarching geomorphic controls influence the delivery of sediment to the lake and may reduce or enhance the hydrometeorological signal contained in the varves. An additional influence for calibration of the varve record to meteorological observations is the role that melt season thermal inversions have on temperature extrapolation in the High Arctic. Meteorological stations at sea level may not be representative of the surrounding region, thereby reducing the accuracy of vertical temperature estimation. Investigation of the inversions in the central Canadian High Arctic demonstrated that melt season inversions are common and increased inversion frequency may potentially have influenced enhanced glacial melt since the late 1980s, with implications for proglacial lake sediment transport and deposition. In coastal Lake J, late Holocene sediments record a relatively unusual accumulation of microbially induced sedimentary structures (MISS). Such a record has not been previously described in the circum-Arctic, although they are known to exist elsewhere. These sediments are produced by the interaction between clastic sedimentation and cyanobacterial growth and production. Although chronological constraint could not be assigned with certainty to the record, statistical study of the laminated sequence suggested a dominant pattern that is plausibly annual. A heuristic model of annual sediment accumulation was developed in order to explore the potential for quasi-annual paleoenvironmental interpretations. / Thesis (Ph.D, Geography) -- Queen's University, 2008-05-22 09:55:12.184

This dissertation investigated the impact of the Surficial Fine-Grained Laminae (SFGL) upon stream biogeochemical cycles to constrain stream C and N budgets. Collection and analysis of 8 years of transported sediment elemental and isotopic signatures, weekly, from a SFGL dominated stream, a novel dissolved C and N dataset, statistical and time-series analysis of sediment and dissolved data, and development of a comprehensive modeling framework that couples hydrodynamics, sediment, C and N biogeochemistry, and stable isotope sub-models to simulate fluvial C and N budgets was used. SFGL C modeling suggests benthic particulate C stocks and transport vary seasonally and annually but are in a state of long-term equilibrium which is governed by negative feedback mechanisms whereby high POC export due to extreme hydrologic events and high frequency hydrologic events reduces benthic particulate C stocks and inhibits benthic particulate C growth. Model distribution fitting suggests transported particulate C in SFGL streams is Gamma distributed; in which statistical moments are governed by variability of the SFGL. Stable isotope un-mixing of the bed source suggests that the SFGL has varying levels of carbon quality seasonally and annually, in which non-equilibrium conditions stem from extreme depositional events. Coupling stable isotope mass balance and SFGL fractionation processes into water quality modeling frameworks, reduced uncertainty of the C budget by nearly 60%, suggesting algal sloughing constitutes nearly 40% of the total organic C budget, shifting the balance from dissolved C to particulate C dominated. Time series analysis of the eight year dataset suggest nitrogen dynamics in the SFGL dominated stream were consistent with existing conceptual models when algal biomass is the prominent organic matter source in the SFGL, but contradicts conventional wisdom in winter through late spring when abiotic sorption appears prominent. The development of a new numerical model to simulate the fluvial N budget couples this new conceptual model of SFGL stream N dynamics to isotope mass-balances and C dynamics in order to provide a comprehensive management tool for restoration engineers. Meta-analysis and upscaling of results for regional to global scales will enable researchers to place the role of the SFGL in a broader context.

Parmi les protéoglycannes à héparane sulphate (HSPGs) des lames basales, le perlécane présente un rôle majeur dans la morphogénèse de l'épiderme mais également dans la survie et la différenciation des kératinocytes. Celui‐ci régulerait ces processus en contrôlant la biodisponibilité des facteurs de croissance. Au cours de ce travail, nous avons étudié l'expression du perlécane dans la peau humaine au cours du vieillissement intrinsèque et son implication dans les défauts de l'épiderme liés à l'âge. Une analyse immunohistologique sur une cohorte de peau normale humaine provenant de donneurs allant de 22 à 73 ans, a révélé une diminution drastique du perlécane au niveau de la jonction dermo‐épidermique et des capillaires dermiques au cours de l'âge. Des études biochimiques combinées à des analyses génomiques ont pu démontrer que la diminution de l'expression du perlécane n'était pas due à une dégradation de la protéine mais à une diminution de sa régulation transcriptionnelle par les kératinocytes. Par ailleurs, la conception et la caractérisation de modèles de peaux reconstruites in vitro combinant des cellules provenant de différents âges a permis d'établir une corrélation entre le défaut de synthèse du perlécane et l'épaisseur de l'épiderme. Nous avons montré que l'addition de perlécane natif purifié dans le milieu de culture d'un modèle contenant des kératinocytes âgés a permis de restaurer l'architecture épidermique. L'ensemble de ces résultats démontre ainsi l'importance du perlécane dans l'homéostasie cutanée. Un criblage de composés a permis la sélection de molécules candidates capables de restaurer spécifiquement l'expression du perlécane dans des cultures de kératinocytes et de cellules endothéliales microvasculaires dermiques âgés. Des tests fonctionnels sur les modèles de peaux reconstruites précédemment mis au point, ont permis de démontrer leur capacité à améliorer la morphogénèse de l'épiderme en accord avec les fonctions du perlécane d'origine épithéliale. L'ensemble de nos résultats indique qu'une diminution significative de synthèse du perlécane par les kératinocytes au cours de l'âge participe à l'affinement et aux défauts de différenciation de l'épiderme observés durant le vieillissement cutané / Among basement membrane heparan sulphate proteoglycans (HSPGs), perlecan is known to be involved in epidermal formation and renewal by regulating keratinocyte survival and differentiation. HSPGs are known to be regulators of growth-factor signalling through different mechanisms. We have investigated the expression of perlecan during skin ageing and have examined whether its expression correlates with age-dependant modifications of the epidermal compartment. The immunohistochemical analysis of perlecan in a cohort of human skin samples from donors of ages ranging from 22 to 73 years revealed a strong decrease of its expression with age in good correlation with reduction of the epidermal thickness. Genomic analyses of keratinocytes isolated from these biopsies combined with further characterization of perlecan from aged donors revealed that the observed decreased expression is most likely a consequence of a reduced synthesis rather than a protein degradation or a deficient supramolecular exposure. The design and characterization of human skin models engineered with cells from donors of various ages confirmed this hypothesis and revealed that aged keratinocytes showing deficiency in perlecan production and deposit in the basement membrane, also displayed inability to form a multilayed epidermis. Addition of purified perlecan in the culture medium of these skin equivalents enhanced the epidermal thickness and restored a well-differentiated multilayed epithelium. Biological screening of a library compounds allowed the selection of candidates able to increase the expression of epithelial and endothelial-derived perlecan with high specificity. Skin engineering models mimicking ageing human skin demonstrates the capacity of one candidate to restore the perlecan functional failure in promoting epidermal renewal and morphogenesis. Our results suggest that the presence of perlecan in the skin basement membrane appears to be crucial for the maintenance of the epidermal integrity and that its decrease with age may contribute to the epidermal thinning

In recent years, use of composites is increasing in most fields of engineering such as aerospace, automotive, civil construction, marine, prosthetics, etc., because of its light weight, very high specific strength and stiffness, corrosion resistance, high thermal resistance etc. It can be seen that the specific strength of fibers are many orders more compared to metals. Thus, laminated fiber reinforced plastics have emerged to be attractive materials for many engineering applications. Though the uses of composites are enormous, there is always an element of fuzziness in the design of composites. Composite structures are required to be designed to resist high stresses. For this, one requires a reliable failure criterion. The anisotropic behaviour of composites makes it very difficult to formulate failure criteria and experimentally verify it, which require one to perform necessary bi-axial tests and plot the failure envelopes. Failure criteria are usually based on certain assumption, which are some times questionable. This is because, the failure process in composites is quite complex. The failure in a composite is normally based on initiating failure mechanisms such as fiber breaks, fiber compressive failure, matrix cracks, matrix crushing, delamination, disbonds or a combination of these. The initiating failure mechanism is the one, which is/are responsible for initiating failure in a laminated composites. Initiating failure mechanisms are generally dependant on the type of loading, geometry, material properties, condition of manufacture, boundary conditions, weather conditions etc. Since, composite materials exhibit directional properties, their applications and failure conditions should be properly examined and in addition to this, robust computational tools have to be exploited for the design of structural components for efficient utilisation of these materials. Design of structural components requires reliable failure criteria for the safe design of the components. Several failure criteria are available for the design of composite laminates. None of the available anisotropic strength criteria represents observed results sufficiently accurate to be employed confidently by itself in design. Most of the failure criteria are validated based on the available uniaxial test data, whereas, in practical situations, laminates are subjected to at least biaxial states of stresses. Since, the generation of biaxial test data are very difficult and time consuming to obtain, it is indeed a necessity to develop computational tools for modelling the biaxial behavior of the composite laminates. Understanding of the initiating failure mechanisms and the development of reliable failure criteria is an essential prerequisite for effective utilization of composite materials. Most of the failure criteria, considers the uniaxial test data with constant shear stress to develop failure envelopes, but in reality, structures are subjected to biaxial normal stresses as well as shear stresses. Hence, one can develop different failure envelopes depending upon the percentage of the shear stress content. As mentioned earlier, safe design of the composite structural components require reliable failure criterion. Currently two broad approaches, namely, (1) Damage Tolerance Based Design and (2)Failure Criteria Based Design are in use for the design of laminated structures in aerospace industry. Both approaches have some limitations. The damage tolerance based design suffers from a lack of proper definition of damage and the inability of analytical tools to handle realistic damage. The failure criteria based design, although relatively, more attractive in view of the simplicity, it forces the designer to use unverified design points in stress space, resulting in unpredictable failure conditions. Generally, failure envelopes are constructed using 4 or 5 experimental constants. In this type of approach, small experimental errors in these constants lead to large shift in the failure boundaries raising doubts about the reliability of the boundary in some segments. Further, they contain segments which have no experimental support and so can lead to either conservative or nonconservative designs. Conservative design leads to extra weight, a situation not acceptable in aerospace industry. Whereas, a nonconservative design, is obviously prohibitive, as it implies failure. Hence, both the damage tolerance based design and failure criteria based design have limitations. A new method, which combines the advantages of both the approaches is desirable. This issue is also thoroughly debated in many international conference on composites. Several pioneers in the composite industry indicated the need for further research work in the development of reliable failure criteria. Hence, this is motivated to carry out research work for the development of new failure criterion for the design of composite structures. Several experts meetings held world wide towards the assessment of existing failure theories and computer codes for the design of composite structures. One such meeting is the experts meeting held at United Kingdom in 1991.This meeting held at St. Albans(UK) on ’Failure of Polymeric Composites and Structures: Mechanisms and Criteria for the Prediction of Performance’, in 1991 by UK Science & Engineering Council and UK Institute of Mechanical Engineers. After thorough deliberations it was concluded that 1. There is no universal definition of failure of composites. 2. There is little or lack of faith in the failure criteria that are in current use and 3. There is a need to carry out World Wide Failure Exercise(WWFE) Based on the experts suggestions, Hinton and Soden initiated the WWFE in consultation with Prof.Bryan Harris (Editor, Journal of Composite Science and Tech-nology)to have a program to get comparative assessment of existing failure criteria and codes with following aims 1. Establish the current level of maturity of theories for predicting the failure response of fiber reinforced plastic(FRP)laminates. 2. Closing the knowledge gap between theoreticians and design practitioners in this field. 3. Stimulating the composites’ community into providing design engineers with more robust and accurate failure prediction methods, and the confidence to use them. The organisers invited pioneers in the composite industry for the program of WWFE. Among the pioneer in the composite industry Professor Hashin declined to participate in the program and had written a letter to the organisers saying that, My only work in this subject relates to failure criteria of unidirectional fiber composites, not to laminates. I do not believe that even the most complete information about failure of single plies is sufficient to predict the failure of a laminate, consisting of such plies. A laminate is a structure which undergoes a complex damage process (mostly of cracking) until it finally fails. The analysis of such a process is a prerequisite for failure analysis. ”While significant advances have been made in this direction we have not yet arrived at the practical goal of failure prediction”. Another important conference held in France in 1999, Composites for the next Millennium (Proceedingof Symposium in honor of S.W.Tsaion his 70th Birth Day Torus, France, July 2-3, 1999, pp.19.) also concludedon similar line to the meeting held at UK in 1991. Paul A Lagace and S. Mark Spearing, have pointed out that, by referring to the article on ’Predicting Failure in Composite Laminates: the background to the exercise’, by M.J.Hinton & P.D.Soden, Composites Science and Technology, Vol.58, No.7(1998), pp.1005. ”After Over thirty years of work ’The’ composite failure criterion is still an elusive entity”. Numerous researchers have produced dozens of approaches. Hundreds of papers, manuscripts and reports were written and presentations made to address the latest thoughts, add data to accumulated knowledge bases and continue the scholarly debate. Thus, the out come of these experts meeting, is that, there is a need to develop new failure theories and due to complexities associated with experimentation, especially getting bi-axial data, computational methods are the only viable alternative. Currently, biaxial data on composites is very limited as the biaxial testing of laminates is very difficult and standardization of biaxial data is yet to be done. All these experts comments and suggestions motivated us to carry out research work towards the development of new failure criterion called ’Failure Mechanism Based Failure Criterion’ based on initiating failure mechanisms. The objectives of the thesis are 1. Identification of the failure mechanism based failure criteria for the specific initiating failure mechanism and to assign the specific failure criteria for specific initiating failure mechanism, 2. Use of the ’failure mechanism based design’ method for composite pressurant tanks and to evaluate it, by comparing it with some of the standard ’failure criteria’ based designs from the point of view of overall weight of the pressurant tank, 3. Development of new failure criterion called ’Failure Mechanism Based Failure Criterion’ without shear stress content and the corresponding failure envelope, 4. Development of different failure envelopes with the effect of shear stress depending upon the percentage of shear stress content and 5. Design of composite laminates with the Failure Mechanism Based Failure Criterion using optimization techniques such as Genetic Algorithms(GA) and Vector Evaluated Particle Swarm Optimization(VEPSO) and the comparison of design with other failure criteria such as Tsai-Wu and Maximum Stress failure criteria. The following paragraphs describe about the achievement of these objectives. In chapter 2, a rectangular panel subjected to boundary displacements is used as an example to illustrate the concept of failure mechanism based design. Composite Laminates are generally designed using a failure criteria, based on a set of standard experimental strength values. Failure of composite laminates involves different failure mechanisms depending upon the stress state and so different failure mechanisms become dominant at different points on the failure envelope. Use of a single failure criteria, as is normally done in designing laminates, is unlikely to be satisfactory for all combination of stresses. As an alternate use of a simple failure criteria to identify the dominant failure mechanism and the design of the laminate using appropriate failure mechanism based criteria is suggested in this thesis. A complete 3-D stress analysis has been carried out using a general purpose NISA Finite Element Software. Comparison of results using standard failure criteria such as Maximum Stress, Maximum Strain, Tsai-Wu, Yamada-Sun, Maximum Fiber Strain, Grumman, O’brien, & Lagace, indicate substantial differences in predicting the first ply failure. Results for Failure Load Factors, based on the failure mechanism based approach are included. Identification of the failure mechanism at highly stressed regions and the design of the component, to withstand an artificial defect, representative this failure mechanism, provides a realistic approach to achieve necessary strength without adding unnecessary weight to the structure. It is indicated that the failure mechanism based design approach offers a reliable way of assessing critically stressed regions to eliminate the uncertainties associated with the failure criteria. In chapter 3, the failure mechanism based design approach has been applied to a composite pressurant tanks of upper stages of launch vehicles and propulsion systems of space crafts. The problem is studied using the failure mechanism based design approach, by introducing an artificial matrix crack representative of the initiating failure mechanism in the highly stressed regions and the strain energy release rate (SERR) are calculated. The total SERR value is obtained as 3330.23 J/m2, which is very high compared to the Gc(135 J/m2) value, which means the crack will grow further. The failure load fraction at which the crack has a tendency to grow is estimated to be 0.04054.Results indicates that there are significant differences in the failure load fraction for different failure criteria.Comparison with Failure Mechanism Based Criterion (FMBC) clearly indicates matrix cracks occur at loads much below the design load yet fibers are able to carrythe design load. In chapter 4, a Failure Mechanism Based Failure Criterion(FMBFC)has been proposed for the development of failure envelope for unidirectional composite plies. A representative volume element of the laminate under local loading is micromechanically modelled to predict the experimentally determined strengths and this model is then used to predict points on the failure envelope in the neighborhood of the experimental points. The NISA finite element software has been used to determine the stresses in the representative volume element. From these micro-stresses, the strength of the lamina is predicted. A correction factor is used to match the prediction of the present model with the experimentally determined strength so that, the model can be expected to provide accurate prediction of the strength in the neighborhood of the experimental points. A procedure for the construction of the failure envelope in the stress space has been outlined and the results are compared with the some of the standard and widely used failure criteria in the composite industry. Comparison of results with the Tsai-Wu failure criterion shows that there are significant differences, particularly in the third quadrant, when the ply is under bi-axial compressive loading. Comparison with maximum stress criterion indicates better correlation. The present failure mechanism based failure criterion approach opens a new possibility of constructing reliable failure envelopes for bi-axial loading applications, using the standard uniaxialtest data. In chapter 5, the new failure criterion for laminated composites developed based on initiating failure mechanism as mentioned in chapter 4 for without shear stress condition is extended to obtain the failure envelopes with the shear stress condition. The approach is based on Micromechanical analysis of composites, wherein a representative volume consists of a fiber surrounded by matrix in appropriate volume fraction and modeled using 3-D finite elements to predict the strengths.In this chapter, different failure envelopes are developed by varying shear stress say from 0% of shear strength to 100% of shear strength in steps of 25% of shear strength. Results obtained from this approach are compared with Tsai-Wu and Maximum stress failure criteria. The results show that the predicted strengths match more closely with maximum stress criterion. Hence, it can be concluded that influence of shear stress on the failure of the lamina is of little consequence as far as the prediction of strengths in laminates. In chapter 6, the failure mechanism based failure criterion, developed by the authors is used for the design optimization of the laminates and the percentage savings in total weight of the laminate is presented. The design optimization of composite laminates are performed using Genetic Algorithms. The genetic algorithm is one of the robust tools available for the optimum design of composite laminates. The genetic algorithms employ techniques originated from biology and dependon the application of Darwin’s principle of survival of the fittest. When a population of biological creatures is permitted to evolve over generations, individual characteristics that are beneficial for survival have a tendency to be passed on to future generations, since individuals carrying them get more chances to breed. In biological populations, these characteristics are stored in chromosomal strings. The mechanics of natural genetics is derived from operations that result in arranged yet randomized exchange of genetic information between the chromosomal strings of the reproducing parents and consists of reproduction, cross over, mutation, and inversion of the chromosomal strings. Here, optimization of the weight of the composite laminates for given loading and material properties is considered. The genetic algorithms have the capability of selecting choice of orientation, thickness of single ply, number of plies and stacking sequence of the layers. In this chapter, minimum weight design of composite laminates is presented using the Failure Mechanism Based(FMB), Maximum Stress and Tsai-Wu failure criteria. The objective is to demonstrate the effectiveness of the newly proposed FMB Failure Criterion(FMBFC) in composite design. The FMBFC considers different failure mechanisms such as fiber breaks, matrix cracks, fiber compressive failure, and matrix crushing which are relevant for different loadin gconditions. FMB and Maximum Stress failure criteria predicts byupto 43 percent savings in weight of the laminates compared to Tsai-Wu failure criterion in some quadrants of the failure envelope. The Tsai-Wu failure criterion over predicts the weight of the laminate by up to 86 percent in the third quadrant of the failure envelope compared to FMB and Maximum Stress failure criteria, when the laminate is subjected to biaxial compressive loading. It is found that the FMB and Maximum Stress failure criteria give comparable weight estimates. The FMBFC can be considered for use in the strength design of composite structures. In chapter 7, Particle swarm optimization is used for design optimization of composite laminates. Particle swarm optimization(PSO)is a novel meta-heuristic inspired by the flocking behaviour of birds. The application of PSO to composite design optimization problems has not yet been extensively explored. Composite laminate optimization typically consists in determining the number of layers, stacking sequence and thickness of ply that gives the desired properties. This chapter details the use of Vector Evaluated Particle Swarm Optimization(VEPSO) algorithm, a multi-objective variant of PSO for composite laminate design optimization. VEPSO is a modern coevolutionary algorithm which employs multiple swarms to handle the multiple objectives and the information migration between these swarms ensures that a global optimum solution is reached. The current problem has been formulated as a classical multi-objective optimization problem, with objectives of minimizing weight of the component for a required strength and minimizing the totalcost incurred, such that the component does not fail. In this chapter, an optimum configuration for a multi-layered unidirectional carbon/epoxy laminate is determined using VEPSO. The results are presented for various loading configurations of the composite structures. The VEPSO predicts the same minimum weight optimization and percentage savings in weight of the laminate when compared to GA for all loading conditions.There is small difference in results predicted by VEPSO and GA for some loading and stacking sequence configurations, which is mainly due to random selection of swarm particles and generation of populations re-spectively.The difference can be prevented by running the same programme repeatedly. The Thesis is concluded by highlighting the future scope of several potential applications based on the developments reported in the thesis.