Rozprawy doktorskie na temat „Damage”

This study has investigated thresholds of damage for privately owned low-rise residential properties damaged by ground subsidence or heave movement. The primary focus of the research objectives has been the uncertainties created by subsidence damage. The study investigates thresholds of damage that can be used to assess the remedial action necessary for low-rise residential properties damaged by ground subsidence or heave movement. After investigating thresholds of damage, the study subsequently considers the implications that thresholds of damage would create if applied in practice. The research was carried out through the collection and analysis of 236 case study properties. Each case study represents a privately owned low-rise residential property that was thought to have been damaged by ground subsidence or heave movement. The research has considered properties damaged by subsidence or heave movement caused by leaking drains, clay subsoil shrinkage or expansion and subsidence caused by coal-mining. Case study information has been gathered from a variety of sources, using data collected by professionally qualified chartered engineers, surveyors or other specialists. In addition to these case studies, the research has employed semi-structured interviews in order to consider the implications that thresholds of damage would create if applied in practice. The research found that the evaluation of visible damage is a highly subjective matter and that any thresholds based upon an assessment of visible damage are an unreliable method to consider whether or not a property requires substantive repairs. The most robust threshold of damage which is found to emerge was to evaluate whether or not the movement causing the damage in the property is long-term progressive. The consequences of implementing this threshold of damage have been investigated. It has been concluded that if this threshold of damage was adopted, it could lead to both reductions in payments necessary to repair subsidence or heave damage and it could also reduce some of the uncertainties associated with subsidence.

The histone H2AX has been established as a reliable biomarker of DNA damage, becoming phosphorylated rapidly following damage in discrete foci which can be correlated with DNA DSB number. In the present study, the phosphorylation of H2AX was used as a marker of DNA DSB damage to compare and contrast the damage induced by ionizing radiation, the topo II poison, etoposide, and the topo II catalytic inhibitor, ICRF-193. To examine the DNA damage numbers at time-points in the 24 hours following exposure to these damaging agents. Topo lIP null cells were used to investigate the contribution of topo II a and Pthese damage responses and the Trapped in Agarose DNA Immunostaining assay was utilised to quantify the numbers of topo II_DNA complexes formed in response to these agents. This study aimed to examine the levels of DNA damage following exposure to these damaging agents and to investigate differences in the complement of proteins associated with DNA damage-induced foci. By using both the y-H2AX and TARDIS assays and protein colocalisation techniques, the studies detailed here presents novel findings on the differing damage responses induced following these three agents.

Cílem této práce je návrh a implementace aplikace pro simulaci poškození umělého otisku prstu. Při studiu jsem se soustředil hlavně na projekt SFinGe, který je průkopníkem v této oblasti. Specifikoval jsem přesněji oblast zájmu na optický či kapacitní senzor a poškození otisků prstů v závislosti na tlaku a vlhkosti, poškození a pošpinění senzoru a deformaci pokožky. Navrhl jsem způsob implementace těchto vlivů poškozujících umělý otisk prstu tak, aby se lépe podobal reálným otiskům. Tyto metody využívají morfologické operátory a model plastického zkreslení u otisků prstů. Výsledky nejúspěšnějších metod mají o 62.5% horší skóre v komerčním produktu oproti originálu a o jednu třídu horší hodnocení dle normy pro kvalitu obrazu otisku prstu. Přínosem této práce je tedy poškození umělých otisků tak, že prokazatelně dosahují horších výsledků než originál a návrh aplikace, která umožňuje rozšíření o další metody.

In this thesis, the mechanical behavior of a timber joint has been studied. The main task is to model the mechanical behavior of the joint as good as possible. To be able to solve the numerical instabilities of the timber joints, a deeper look needs to be done to the modelling of the wooden material and the steel wood contact. For this thesis a previously developed 3D numerical damage model of wood has been studied. This model has been elaborated by Sandhaas(2012) and it describes crack initiation and propagation of the material based on the concepts of continuum damage mechanics. The basic material model of wood has been implemented as a user material in the UMAT subroutine of ABAQUS. The developed model is giving some numerical instabilities due to the extreme distortion of the elements. During this thesis the model has been enhanced in order to be able to represent the mechanical behavior of wood as good as possible and solve the problem of the model. The modelling outcomes were compared to the results obtained by experimental tests (ref. to Sandaas,2012).The results showed that the first model, a tension test parallel-to grain, had been enhanced. Indeed the results got closer to the experimental value than the original model’s results did. The second model represented a timber joint with slotted-in steel plate with a dowel. The analysis were done with different wood spieces (spruce, beech and azobè). Regarding the spruce, the analysis reached fairly accurate results concerning the capacity load but they were less precise regarding the displacement and the stiffness. The prediction quality was rather poor for the other two species, beech and azobè. It is necessary to find other ways to further enhance the model.Even today a model that is able to represent all three fields (stiffness, capacity load and displacement) accurately doesn’t exist. Good results of one of these lead to bad results of the others. Modelling wood then still represents an evolving challenge.

This thesis is about using structural-dynamics based methods to address the existing challenges in the field of Structural Health Monitoring (SHM). Particularly, new structural-dynamics based methods are presented, to model areas of damage, to do damage diagnosis and to estimate and predict the sensitivity of structural vibration properties like natural frequencies to the presence of damage. Towards these objectives, a general analytical procedure, which yields nth-order expressions governing mode shapes and natural frequencies and for damaged elastic structures such as rods, beams, plates and shells of any shape is presented. Features of the procedure include the following: 1. Rather than modeling the damage as a fictitious elastic element or localized or global change in constitutive properties, it is modeled in a mathematically rigorous manner as a geometric discontinuity. 2. The inertia effect (kinetic energy), which, unlike the stiffness effect (strain energy), of the damage has been neglected by researchers, is included in it. 3. The framework is generic and is applicable to wide variety of engineering structures of different shapes with arbitrary boundary conditions which constitute self adjoint systems and also to a wide variety of damage profiles and even multiple areas of damage. To illustrate the ability of the procedure to effectively model the damage, it is applied to beams using Euler-Bernoulli and Timoshenko theories and to plates using Kirchhoff's theory, supported on different types of boundary conditions. Analytical results are compared with experiments using piezoelectric actuators and non-contact Laser-Doppler Vibrometer sensors. Next, the step of damage diagnosis is approached. Damage diagnosis is done using two methodologies. One, the modes and natural frequencies that are determined are used to formulate analytical expressions for a strain energy based damage index. Two, a new damage detection parameter are identified. Assuming the damaged structure to be a linear system, the response is expressed as the summation of the responses of the corresponding undamaged structure and the response (negative response) of the damage alone. If the second part of the response is isolated, it forms what can be regarded as the damage signature. The damage signature gives a clear indication of the damage. In this thesis, the existence of the damage signature is investigated when the damaged structure is excited at one of its natural frequencies and therefore it is called ``partial mode contribution". The second damage detection method is based on this new physical parameter as determined using the partial mode contribution. The physical reasoning is verified analytically, thereupon it is verified using finite element models and experiments. The limits of damage size that can be determined using the method are also investigated. There is no requirement of having a baseline data with this damage detection method. Since the partial mode contribution is a local parameter, it is thus very sensitive to the presence of damage. The parameter is also shown to be not affected by noise in the detection ambience.

The primary objective of this work is to experimentally examine the effect of various geometric parameters on the impact damage and damage tolerance of thin carbon/epoxy plate and panel structures. Due to the number of parameters involved in a low velocity impact event and the complexity of the damage created, determining what effect individual parameters have is extremely demanding, especially when some of the parameters may even be coupled. However, by experimentally simulating in a controlled manner, either the impact event or the damage created, the effect of individual geometric parameters can be isolated and determined. A quasi-static indentation test has been used to simulate an impact event. The parameters of indenter size, nose shape, plate size and boundary condition, were examined. Four different plate failure modes were identified. Indenter nose shape was found to be the dominant geometric parameter, as a change in nose shape resulted in a change in failure mode and hence maximum load. From this work, a set of geometric parameters was selected for impact testing. Impact testing at various Incident Kinetic Energies (IKE) was performed on an instrumented drop weight impact rig. From examination of internal and external damage, the development of damage to increasing IKE was determined and shown to have four distinctive phases. Coupled with strike and rebound velocity measurementsa, non-linear relationship between IKE-damage area was established and a delamination threshold energy level of 1.1 J was calculated. Damaget olerance assessmenot f impacted panels was then performed in a Compression-After- Impact (CAI) rig. Strain gauge responses allowed global and local behaviour to be compared to intact specimens. It was found that once a critical damage size was surpassed, a gradual nonlinear degradation in compressive strength was observed until a point was reached where no further degradation in performance was attained. Furthermore, propagation of internal damage in a stable and unstable manner was directly linked to the nature of sublaminate buckling behaviour. Damaget olerance assessmenot f artificially delaminatedp anels loaded in compressionw as then performed. A single artificial delamination of various size, shape and orientation, embedded at the centre of a panel was examined. Delamination width was found to be the dominant geometric parameter. Hence, when comparing a circular delamination to an elliptical one of the same area, the effect of orientation and shape is aspect ratio dependent. Finally, a comparison of impacted and artificially delaminated panels was made.

A local isotropic damage coupled hyperelastic-plastic framework is formulated in principal axes where thermo-mechanical extensions are also addressed. It is shown that, in a functional setting, treatment of many damage growth models, including ones originated from phenomenological models (with formal thermodynamical derivations), micro-mechanical models or fracture criteria, proposed in the literature, is possible. Quasi-unilateral damage evolutionary forms are given with special emphasis on the feasibility of formulations in principal axes. Local integration procedures are summarized starting from a full set of seven equations which are simplified step by step initially to two and finally to one where different operator split methodologies such as elastic predictor-plastic/damage corrector (simultaneous plastic-damage solution scheme) and elastic predictor-plastic corrector-damage deteriorator (staggered plasticdamage solution scheme) are given. For regularization of the post peak response with softening due to damage and temperature, Perzyna type viscosity is devised. Analytical forms accompanied with algorithmic expressions including the consistent material tangents are derived and the models are implemented as UMAT and UMATHT subroutines for ABAQUS/Standard, VUMAT subroutines for ABAQUS/Explicit and UFINITE subroutines for MSC.Marc. The subroutines are used in certain application problems including numerical modeling of discrete internal cracks, namely chevron cracks, in direct forward extrusion process where comparison with the experimental facts show the predicting capability of the model, isoerror map production for accuracy assessment of the local integration methods, and development two novel necking triggering methods in the context of a damage coupled environment.

Thesis (M.S.) University of Missouri-Columbia, 2006.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 29, 2007) Includes bibliographical references.

Vaccination aims to prevent infectious disease, and is internationally acclaimed as a major contributor to public health. Although vaccines have many benefits, there are people who claim that they or their infant children have been injured, often permanently and severely, by the powerful biological agents introduced into their bodies by vaccination. The object of this thesis is to determine whether the law in England and Wales relating to vaccine damage is in need of reform. The answer to this question is determined by a moral and legal analysis of current vaccination policy and practice. The existing literature consists primarily of medical papers discussing the possibility of vaccine damage and legal discourses concerning compensation and consent to treatment. Detailed background information comes from in-depth semi-structured interviews with a consultant epidemiologist at the Public Health Laboratory Service and three organisers of Justice Awareness Basic Support (JABS), a vaccine information and support group. The main originality of the thesis is the information provided by approximately 360 responses to each of two surveys. Parents of pre-school children were surveyed about their experiences of, and views on, current vaccination policy and practice. Members of JABS who believe their children to be vaccine-damaged provided information about the vaccines which appear to have caused harm, as well as their experiences of, and views on, the legal routes to financial redress. The findings provide evidence of a dearth of reliable medical data about vaccine safety, and of some ethically unacceptable practices associated with infant vaccination. They also reveal that, theoretically and in the view of users, legal provision for the victims of vaccine damage in England and Wales is unsatisfactory. These factors combine to indicate that the law relating to compensation for vaccine damage is in need of reform. The thesis therefore concludes with suggestions for further research and some modifications to current law and policy. There should be a statutory scheme awarding compensatory, rather than token, payments to victims. Awards should be made subject to a generous test of causation, such as that which exists in respect of the US Vaccine Injury Compensation Program. Incentive payments to GPs should be discontinued, parents should be offered choices of vaccine, and vaccine promotional literature for healthcare workers and parents should present a balanced view of all available research. Above all, it is essential that these measures be supported by large-scale, independent medical research into the nature of possible links between vaccines and damage.

There is a lot of different kind of games which creates many different ways to balance the difficulty of games. This study will look at if damage output from a player is a good variable to scale in order to create a better balance and make the game feel more rewarding overall, based on that a game would be enjoyable if a player feels that it is rewarding to play the game. By letting both inexperienced and avid players test a part of a game with different settings for the damage output to see if the players finds the game to be more rewarding if the difficulty is set to a higher setting (lower damage output). The conclusion is that it is that damage output cannot directly affect how overall rewarding a player finds the game, but can affect other variables that in turn make the game feel more rewarding.

RESUMO:Em 1994 a acrilamida (AA) foi classificada pela IARC como um provável cancerígeno para o homem. Para além da utilização de AA em numerosas aplicações industriais, a AA está também presente numa grande variedade de alimentos ricos em amido e processados a temperaturas elevadas. Esta exposição através da ingestão de produtos alimentares despoletou elevadas preocupações ao nível do risco para a saúde pública e poderá implicar um risco adicional para o aparecimento de cancro. A glicidamida (GA), o metabolito epóxido formado a partir da oxidação da AA provavelmente através do citocromo P450 2E1, é considerada por vários estudos, o principal responsável pela carcinogenicidade da AA. Actualmente existe uma escassez de resultados relativamente aos mecanismos de genotoxicidade da AA e GA em células de mamífero. Por este motivo, o objectivo deste estudo centra-se na avaliação das consequências genéticas da exposição à AA e GA, recorrendo-se para tal ao uso de células de mamífero como modelo. Tendo como base este objectivo avaliou-se a citotoxicidade da AA e GA, através do ensaio do MTT, e realizaram-se dois testes citogenéticos, o teste das aberrações cromossómicas (CAs) e o teste da troca de cromátides irmãs (SCEs), de modo a avaliar as lesões de DNA induzidas por estes compostos em células de hamster Chinês V79. Os resultados globalmente mostraram que a GA é mais citotóxica e clastogénica do que a AA. No âmbito deste trabalho, foi também efectuada a quantificação de aductos específicos de DNA, nomeadamente N7-(2-carbamoil-2-hidroxietil)guanina (N7-GA-Gua) e N3-(2-carbamoil-2-hidroxietil)adenina (N3-GA-Ade). Os resultados obtidos permitem afirmar que os níveis de N7-GA-Gua e a concentração de GA apresentam uma relação linear dose-resposta. Foi também identificada uma óptima correlação entre os níveis de N7-GA-Gua e a frequência de troca de cromátides irmãs. Adicionalmente, e de forma a compreender os mecanismos de toxicidade da AA, estudaram-se os mecanismos dependentes da modulação do glutationo reduzido (GSH), nomeadamente da butionina sulfoximina (BSO), um inibidor da síntese de GSH, do GSH-monoetil estér (GSH-EE), um composto permeável nas células e que é intra-celularmente hidrolisado a GSH e ainda do GSH adicionado exogenamente ao meio de cultura, em células V79. Os resultados obtidos reforçaram o papel da modulação do GSH nos efeitos de citotoxicidade e clastogenicidade da AA. Para além dos estudos efetuados com células V79, procedeu-se também à determinação da frequência de SCEs, à quantificação de aductos específicos de DNA, bem como ao ensaio do cometa alcalino em amostras de dadores saudáveis expostos à AA e GA. Tanto os resultados obtidos através do ensaio das SCE, como pela quantificação de aductos específicos de DNA, ambos efectuados em linfócitos estimulados, originaram resultados comparáveis aos obtidos anteriormente para as células V79, reforçando a ideia de que a GA é bastante mais genotóxica do que a AA. Por outro lado, os resultados obtidos pelo ensaio do cometa para exposição à AA e GA mostraram que apenas esta última aumenta o nível das lesões de DNA. Outro objectivo deste trabalho, foi a identificação de possíveis associações existentes entre as lesões de DNA, quantificadas através do ensaio das SCEs e do cometa, e biomarcadores de susceptibilidade, tendo em conta os polimorfismos genéticos individuais envolvidos na destoxificação e nas vias de reparação do DNA (BER, NER, HRR e NHEJ) em linfócitos expostos à GA. Tal permitiu identificar associações entre os níveis de lesão de DNA determinados através do ensaio das SCEs, e os polimorfismos genéticos estudados, apontando para uma possível associação entre o GSTP1 (Ile105Val) e GSTA2 (Glu210Ala) e a frequência de SCEs. Por outro lado, os resultados obtidos através do ensaio do cometa sugerem uma associação entre as lesões de DNA e polimorfismos da via BER (MUTYH Gln335His e XRCC1 Gln39Arg) e da via NER (XPC Ala499val e Lys939Gln), considerando os genes isoladamente ou combinados. Estes estudos contribuem para um melhor entendimento da genotoxicidade e carcinogenicidade da AA e GA em células de mamífero, bem como da variabilidade da susceptibilidade individual na destoxificação e reparação de lesões de DNA provocadas pela exposição a estes xenobióticos alimentares. ----------- ABSTRACT:Acrylamide (AA) has been classified as a probable human carcinogen by IARC. Besides being used in numerous industrial applications, AA is also present in a variety of starchy cooked foods. This AA exposure scenario raised concerns about risk in human health and suggests that the oral consumption of AA is an additional risk factor for cancer. A considerable number of findings strongly suggest that the reactive metabolite glycidamide (GA), an epoxide generated presumably by cytochrome P450 2E1, plays a central role in AA carcinogenesis. Until now there are a scarcity of results concerning the mechanisms of genotoxicity of AA and GA in mammalian cells. In view of that, the study described in this thesis aims to unveil the genetic consequences of AA and GA exposure using mammalian cells as a model system. With this aim we evaluated the cytotoxicity of AA and GA using the MTT assay and subsequently performed two cytogenetic end-points: chromosomal aberrations (CAs) and sister chromatid exchanges (SCEs), in order to evaluate DNA damage induced by these compounds in V79 Chinese hamster cell line. The results showed that GA was more cytotoxic and clastogenic than AA. Within the scope of this thesis the quantification of specific DNA adducts were also performed, namely N7-(2-carbamoyl-2-hydroxyethyl)guanine (N7-GA-Gua) and N3-(2-carbamoyl-2-hydroxyethyl)adenine (N3-GA-Ade). Interestingly, the GA concentration and the levels of N7-GA-Gua presented a linear dose-response relationship. Further, a very good correlation between the levels of N7-GA-Gua and the extent of SCEs were observed. In order to understand the mechanisms of AA-induced toxicity, the modulation of reduced glutathione (GSH)-dependent mechanisms were studied, namely the evaluation of the effect of buthionine sulfoximine (BSO), an effective inhibitor of GSH synthesis, of GSH-monoethyl ester (GSH-EE), a cell permeable compound that is intracellularly hydrolysed to GSH and also of GSH endogenously added to culture medium,z in V79 cell line. The overall results reinforced the role of GSH in the modulation of the cytotoxic and clastogenic effects induced by AA.Complementary to the studies performed in V79 cells, SCEs, specific DNA-adducts and alkaline comet assay in lymphocytes from healthy donors exposed to AA and GA were also evaluated. Both, the frequency of SCE and the quantification of specific GA DNA adducts, produced comparable results with those obtained in V79 cell line, reinforcing the idea that GA is far more genotoxic than AA. Further, the DNA damaging potential of AA and GA in whole blood leukocytes evaluated by the alkaline comet assay, showed that GA, but not AA, increases DNA damage. Additionally, this study aimed to identify associations between DNA damage and biomarkers of susceptibility, concerning individual genetic polymorphisms involved in detoxification and DNA repair pathways (BER, NER, HRR and NHEJ) on the GA-induced genotoxicity assessed by the SCE assay and by the alkaline comet assay. The extent of DNA damage determined by the levels of SCEs induced by GA seems to be modulated by GSTP1 (Ile105Val) and GSTA2 (Glu210Ala) genotypes. Moreover, the results obtained from the comet assay suggested associations between DNA damage and polymorphisms of BER (MUTYH Gln335His and XRCC1 Gln399Arg) and NER (XPC Ala499Val and Lys939Gln) genes, either alone or in combination. The overall results from this study contribute to a better understanding of the genotoxicity and carcinogenicity of AA and GA in mammalian cells, as well as the knowledge about the variability in individual susceptibility involved in detoxification and repair of DNA damage due to these dietary xenobiotics.

Although nondestructive evaluation techniques have been implemented in many industry fields and proved to be useful, they are generally expensive, time consuming, and the results may not always be reliable. To overcome these drawbacks, structural health monitoring (SHM) systems has received significant attention in the past two decades. As structural systems are becoming more complicated and new materials are being developed, new methodologies, theories, and approaches in SHM have been developed for damage detection, diagnosis, and prognosis. Among the methods developed, the guided Lamb wave based SHM can be a promising technique for damage evaluation since it provides reliable damage information through signals propagating over large distance with little loss of amplitude. While this method is effective for damage assessment, the guided Lamb wave contains complicated mode characteristics, i.e. an infinite number of wave modes exist and these modes are generally dispersive. For this reason, a minimum number of wave modes and various signal processing algorithms are implemented to obtain better signal interpretations. Phased array beamsteering is an effective means for damage detection in guided Lamb wave SHM systems. Using this method, the wave energy can be focused at localized directions or areas by controlled excitation time delay of each array element. In this research, two types of transducers are utilized as phased array elements to compare beamsteering characteristics. Monolithic piezoceramic (PZT) transducers are investigated for beamsteering by assuming omnidirectional point sources for each actuator. MacroFiber Composite (MFC) transducers with anisotropic actuation are also studied, considering the wave main lobe width, main lobe magnitude, and side lobe levels. Analysis results demonstrate that the MFC phased arrays perform better than the PZT phased arrays for a range of beamsteering angles and have reduced main lobe width and side lobe levels. Experiments using the PZT and MFC phased arrays on an aluminum plate are also performed and compared to the analysis results. A time-frequency signal processing algorithm coupled with a machine learning method can form a robust damage diagnostic system. Four types of such algorithms, i.e. short time Fourier transform, Wigner-Ville distribution, wavelet transform, and matching pursuit, are investigated to select an appropriate algorithm for damage classification, and a spectrogram based on short time Fourier transform is adopted for its suitability. A machine learning algorithm called Adaboost is chosen due to its effectiveness and high accuracy performance. The classification is preformed using spectrograms and Adaboost for crack and corrosion damages. Artificial cracks and corrosions are created in Abaqus® to obtain the training samples consist of spectrograms. Several beam experiments in laboratory and additional simulations are also performed to get the testing samples for Adaboost. The analysis results show that not only correct damage classification is possible, but the confidence levels of each sample are acquired.
Ph. D.

La difusión de los materiales cerámicos en muchos campos de la industria es amplia y está en fuerte expansión, debido a las excelentes propiedades de estos materiales, ya sean mecánicas, térmicas, tribológicas o biológicas. Sin embargo, su fragilidad intrínseca y falta de fiabilidad limitan una mayor difusión en esas aplicaciones donde se precisa alta resistencia estructural. La producción de composites multilaminares es un camino prometedor para aumentar la fiabilidad de los cerámicos. Los cerámicos multicapa permiten que las propiedades mecánicas sean mejores que las de los componentes, debido a la presencia en la superficie de tensiones residuales de compresión provocadas diferencias de expansión térmica entre las capas.
Las aplicaciones óptimas de estos materiales son las que están relacionadas con las propiedades superficiales; por eso la respuesta a las cargas por contacto son especialmente importantes para caracterizar las propiedades mecánicas y para mejorar el diseño de cerámicos composites avanzados.
Las técnicas de indentación Hertziana son herramientas muy útiles para estudiar este tipo de carga, que por otro lado es difícil de caracterizar por ensayos mecánico tradicionales. El daño por contacto en materiales frágiles aparece principalmente como grietas anillo en la superficie, que pueden desarrollarse como grietas cono, características de este tipo de carga. Este agrietamiento es perjudicial para la funcionalidad del material, y puede llevar al fallo de la pieza. Las cerámicas tenaces, por otro lado, pueden presentar un daño, cuasi-plástico, que se genera debajo la superficie en forma de microagrietamento, y que es causa de deformación inelástica.
En esta tesis, se caracteriza la resistencia al daño por contacto materiales cerámicos en base alúmina, incluyendo todos los aspectos de ese daño, desde la aparición de fisuras superficiales, a la propagación de grietas frágiles en la primera capa y su influencia sobre la resistencia del material, hasta el fallo inducido por carga de contacto. Se comparan medidas experimentales con análisis a los Elementos Finitos de los parámetros involucrados en cada caso, lo que permite formular pautas para una correcta caracterización y diseño de cerámicas multicapas avanzados.
Se vio que la presencia de tensiones residuales es efectiva en mejorar la resistencia a la formación de grieta anillo, sea generada por cargas monotónicas, cíclicas o estáticas.
La alta resistencia frente a este último tipo de carga revela que existen mecanismos de puenteo intergranular que se oponen a la formación de grietas, lo que era inesperado por el tamaño de grano fino, y que se atribuye a un efecto de grieta corta, comparada con la microestructura. Ensayos cíclicos de larga duración mostraron, por otro lado, que en los materiales multicapas aparece daño superficial más severo que en los monolíticos, lo que sugiere un cambio del daño predominante hacía una degradación superficial producida por cuasi-plasticidad.
Las tensiones residuales afectan tanto la longitud como el ángulo de la grieta cono. Se modeló el problema mediante Elementos Finitos y algoritmos de propagación de grieta, lo que permitió predecir el crecimiento de grieta en función tanto de las tensiones residuales, como de otros parámetros microestructurales, y determinar del ángulo de la grieta cono en materiales policristalinos.
La respuesta a cargas remotas de materiales indentados, en otras palabras la degradación de la resistencia, se ve afectada por la geometría de la grieta cono, y por otros factores que son consecuencia de la estructura laminar, tales como las tensiones residuales y la redistribución de carga por el desajuste elástico entre capas. Asimismo, la resistencia por contacto, o sea la resistencia a compresión roma localizada, se ve mejorada en materiales laminares, como consecuencia de las tensiones residuales. Sin embargo, se evidenció que existe el riesgo de que se genere tensión elevada en las capas interiores bajo ambos tipos de carga, y se propusieron consideraciones generales sobre el diseño de materiales laminares.
En definitiva, se consiguió una caracterización exhaustiva de las propiedades de contacto mecánico de los materiales estudiados, y se amplió y mejoró el conocimiento de la propagación de grieta en materiales frágiles policristalinos.
The use of ceramic materials in many industrial fields is spread and ever-increasing, for their excellent properties, either mechanical, thermal, tribological or biological. However, their intrinsic brittleness and lack of reliability are obstacles to further spreading these materials in applications where structural resistance is required. To build multilayered composite structures is a promising way which aims to increase the reliability of ceramics. As it is common in composite materials, layered materials allow the mechanical properties to be superior to those of the constituent materials, in the studied case due to the presence of compressive residual stress in the surface.
The best applications for such materials are those related to the surface properties; for this reason the response to contact loading is especially important to characterize the mechanical properties and to assist in the design of advanced ceramic composites. Hertzian indentation techniques provide a powerful tool to study such type of loading, which is otherwise difficult to characterize with the traditional mechanical testing methodologies.
Contact damage in brittle materials appears mainly as surface ring-cracks, which can develop in a characteristic cone crack. Such fissuration is detrimental to the functionality of the material, and can lead to the failure of the component. Tough ceramics often present another type of damage, the so-called quasi-plasticity, generated as subsurface microcracking and which is cause of inelastic deformation.
In this thesis, alumina-based ceramic laminates were characterized in their resistance to contact damage in all its aspects, starting from the appearance of surface fissures, to the propagation of brittle cracks in the first layer and its influence on the material strength, to the contact loadinginduced failure. Experimental measurements were coupled with Finite Element analysis of the involved parameters, which assisted in formulating comprehensive guidelines for the correct characterization and the design of advanced multilayered ceramics.
The presence of residual stress in ceramic laminates proved to be effective in improving the material resistance to the ring cracking, generated by monotonic, cyclic and longlasting tests.
The better resistance to these latter revealed the existence of grain bridging hindering the crack formation, unexpected in fine-grained alumina and which was related to the small crack character of the ring crack. Longer lasting cyclic tests showed that more severe damage appears in the multilayered materials than in the monolithic one, suggesting a modification of the redominant damage mode to quasi-plastic-derived surface degradation.
Propagation of long cone cracks is affected by residual stress in both the length and angle. An automatic Finite Element model of crack propagation allowed to predict crack growth as a function of both the extrinsic residual stresses and of microstructural parameters, which helped address the long-open question of the cone crack angle on polycrystalline materials.
The response to remote loading of indented materials, in other words the strength degradation, is conditioned by the cone crack geometry, as well as by other factors deriving from the laminated structure, such as the presence of residual stress itself and the load redistribution due to the elastic mismatch between layers. Similarly, the contact strength, i.e. the resistance to local blunt compression, is improved in the composite materials as a consequence of the residual stresses. Nevertheless, the risk of high stress in the lower tensile layers was highlighted for both types of loading and general consideration on the design of laminated materials were proposed.
In the overall, a comprehensive characterization of the contact properties of the studied materials was achieved, and the understanding of crack propagation on brittle polycrystalline materials was broadened and improved.

A prerequisite for a multicellular organism to survive is the ability to correctly replicate and repair DNA while minimizing the number of heritable mutations. To achieve this, cells need a balanced supply of deoxyribonucleoside triphosphates (dNTPs), the precursors for DNA synthesis. The rate-limiting step in de novo biosynthesis of dNTPs is catalyzed by the enzyme ribonucleotide reductase (RNR). The classic eukaryotic RNR enzyme consists of a large and a small subunit. Together, these subunits form a heterotetrameric RNR complex. The larger subunit harbours active sites whereas the smaller subunit contains a stable tyrosyl free radical. Both subunits are required for RNR activity. Since failure to correctly regulate de novo dNTP biosynthesis can lead to misincorporation of nucleotides into DNA, genetic abnormalities and cell death, RNR activity is tightly regulated. The regulation of RNR activity involves cell cycle-specific expression and degradation of the RNR proteins, as well as binding of allosteric effectors to the large RNR subunit. In this thesis, in vitro assays based on purified recombinant RNR proteins, in combination with in vivo assays, have been used successfully to study the regulation of RNR activity in response to DNA damage. I present new findings regarding the function of an alternative mammalian RNR small subunit, and on the role of a small RNR inhibitor protein of fission yeast, during normal growth and after DNA damage. I also show conclusively that there are fundamental differences in the regulation of dNTP biosynthesis between the cells of higher and lower eukaryotes after DNA damage.

This study sought to investigate the consequences of different degrees of oxidative stress on endothelial cells, using a cultured endothelial cell model; principally bovine aortic endothelial cells, subjected to oxidative stress. High concentrations of H2O2 or a superoxide generating system caused rapid endothelial cell death, as evidenced by increased membrane permeability, which could be partially protected by myoglobin. Extracellular H2O2 caused a rapid increase in intracellular peroxidation but was also eliminated by endothelial cells. However, the anti-oxidant capacity of the bovine endothelial cells was very weak and could be overcome by as little as 5 femtomol hydrogen peroxide per cell. The effects were directly related to the amount of H2O2 available to each cell, rather than the concentration. Exposure to relatively low amounts of H2O2 (<0.5 picomol/cell) led to reduced endothelial cell function including prostacyclin production and mitochondrial dehydrogenase activity, and inhibited cell migration and proliferation. The cells showed gradual, partial recovery from these damaging effects. At low amounts (0.1 to 0.5 picomol/cell) H2O2 induced endothelial cell apoptosis within 48 hours of the exposure. After this time, some of the surviving cells showed evidence of senescence and could remain in culture for up to 30 days. Senescence was accompanied by an increase in cytoplasmic volume and accumulation of lipofusion. Investigation of -galactosidase activity suggested that the increased enzyme expression was linked to cell cycle rather than senescence. In conclusion, endothelial cells are very sensitive to oxidative damage but the nature of the damage is related to the degree of oxidative stress. The effects of oxidative stress may play an important role in atherosclerotic and cardiovascular diseases.

This thesis presents a new set of methods to assist the process of ship design for safety with particular reference to collision damage. The study has two principal objectives: " investigations into subdivision aspects of passenger ships to improve their overall survival index " investigations into the subdivision of oil tankers in order to improve the effectiveness against spillage in the event of collision damage. In order to investigate the ship subdivision aspect a damage stability model was needed. A pre-requisite for developing the damage stability software was a robust but flexible method to define the hull and the compartments of subdivision. B-splines have been a popular representationatl ool in computer aided design over the past three decades.T his method, though more complex than other spline techniques such as cubic splines, was adopted with a fourth order basis function in this work. A complete set of spline manipulation libraries and associated numerical solvers were developed for this purpose. In addition to this, a method to define the intersection between the hull and the waterplane in the form of a closed B-spline curve for any given orientation of the vessel in terms of -heel, trim and draught was developed to aid the damage stability calculations. Though the earlier regulations stipulate fixed trim assessments to ease the computational process, it is clearly unsatisfactory and research has confirmed this to be a flawed approach. Free trim calculations on the other hand require an iterative and time consuming process to arrive at the equilibrium trim position for each heel angle. Pawlowski proposed a new method for the stability calculations of a freely floating rig when the unit is arbitrarily orientated to the wind direction. It uses the Euler theorem on the properties of equivolume waterplanes to arrive non-iteratively at the new inclined position. This theory was adapted for use in damage stability calculations and was numerically tested and proved to be sound. Damage stability calculations, though combinatorially large, are also inherently parallel. Parallel Virtual Machines (PVM) is a Message Passing Interface (MPI) developed jointly by ORNL, University of Tennessee, Carnegie Mellon University and the Pittsburgh Supercomputing centre. PVM enables a "virtual configuration" so that a collection of serial, parallel and vector processing machines appear as one large distributed memory computer. PVM was compared with another MPI called Network Linda where the advantage of PVM's user controlled message passing was demonstratedP. VM was used to implement the MJMD Distributed Memory paradigm to exploit this inherent parallelism in damage stability calculations and to obtain speedups. A systematic exploration of the search space for this design problem involves the generation of a large number of internal subdivision configurations. This, coupled with the fact that the design space was multimodal in nature made it suitable to the application of a class of heuristic search algorithms called Genetic Algorithms (GA). A brief description of the mechanisms behind GA is presented along with their mathematical basis in the form of two theorems: the schema theorem and the building block hypothesis. Various techniques for solving constrained optimisation problems with GA was explored. The penalty function method was found to be the most suitable and was finally adopted. The above techniques were applied to the optimisation. of the internal subdivision of passenger ships and cargo ships, oil tankers in particular. For passenger ships, the nature of the 's'-factor formulation on the local index was shown. The multimodal nature of the subdivision problem was highlighted and a GA was used to investigate the optimal subdivision characteristics of the vessel. The 's' factor formulation for cargo ship rules is different to that described by the A. 265 set of regulations for passenger vessels. In addition, the cargo ship rules describe a factor V which accounts for the probabilities of vertical extents of damages. However this formulation does not assign any credit for horizontal subdivision below the waterline. Data on vertical extents and vertical location of damages for cargo ships was collected and analysed in earlier studies done at Newcastle University. This data was used to develop a probability function akin to that developed for the longitudinal extent and longitudinal location so as to give credit for any horizontal subdivisions. The principal objective of this part of the study was to explore the search space for subdivision configurations that would minimize net oil outflow.

Introduction: Patient outcome after trauma is influenced by their immune response to injury. How trauma activates the immune system and why this affects recovery is unclear. This investigation examined three aspects of the immune response after trauma: cytokine production, alarmin release and the innate immune cell populations. Methodology: Timed blood samples were drawn from trauma patients recruited to a prospective observational cohort study at a London Major Trauma Centre. The first sample was drawn at admission, within 2h of injury and prior to intervention in order to capture early inflammation events. Patients were observed until death or discharge for clinical outcomes. Results: Inflammation after traumatic tissue damage can be described in isolation. If haemorrhagic shock is also present, the inflammatory effects cannot be separated using the seven cytokines examined in this investigation. Within 2h of injury, isolated tissue damage is associated with systemic release of intracellular nuclear molecules. Tissue damage combined with shock, is associated with release of different nuclear materials. Low numbers of lymphocytes at 48h from injury are associated with poor clinical outcome. Patients who develop infections and multiple organ dysfunction syndrome during recovery, have high numbers of cytotoxic lymphocytes in their peripheral blood at admission. Conclusion: Inflammation is activated prior to arrival at hospital. Haemorrhagic shock augments the inflammatory response after isolated tissue damage. Tissue damage and blood loss may lead to the release of different alarmin substances. Lymphocytes are implicated in the pathogenesis of poor outcome. The molecular events which lead to poor clinical outcome are activated before hospital admission and prior to intervention. Greater understanding of the activation mechanism(s) may result in development of therapeutics for early delivery, in order to improve patient recovery.

Acoustic emission (AE) is an emerging technique for the condition monitoring of rotating machinery components, including both rolling element bearings and gears. Due to the high frequency range over which AE is sensitive to, AE potentially offers advantages for detection of incipient damage at an early stage of failure when compared to traditional techniques such as vibration. This thesis first investigates the effects of increased speed and load on the generation of AE within cylindrical roller bearings, and determines similarities and differences between AE and vibrational data. A traditional AE sensor was used in conjunction with a Dual Function Sensor (DFS) capable of recording both low frequency AE and vibration. It was shown that increasing speed has the greatest influence on the AE signals produced whereas the effect of load was limited. Order analysis of both AE and vibrational data also demonstrated that characteristic bearing defect frequencies are visible in the AE spectrum but not in the vibrational spectrum. Bearings with seeded defects upon the outer raceway were investigated under a fixed speed and it was found that load increased the energy within the signal frequency spectrum as the damaged increased. Two bearing life tests were also conducted, one accelerated to 12 hours and the second extended to over 2800 hours however as damage detection only occurred after significant damage had developed, it is concluded that AE of seeded defects indicate a false sensitivity. Both life tests were able to demonstrate that signal levels increase as damage propagates over the bearing raceway however it was not possible to determine any advantage of using AE over vibration. AE sensors were also applied to test rigs of increased complexity, including the monitoring a wind turbine planet bearing and a helical gear pair. AE was able to detect cracking of the shaft surface within the wind turbine bearing test rig which was mistaken for being an inner raceway failure, highlighting the difficulty in damage location. A tooth failure occurred during the testing of the helical gear pair however AE was not able to detect growing damage, instead only increasing in amplitude after the tooth had sheared off, similar to the detection from vibrational signals.

The focus of this report is to investigate whether a towboat would be able meet damaged stability requirements. In order to evaluate what type of damage stability requirements could be considered, two damage stability criteria were selected for this investigation: Offshore Supply Vessel and Passenger Vessel Damage Criteria. Two vessels are then evaluated using General Hydrostatic Software (GHS) to find the maximum allowable vertical center of gravity allowed by each set of criteria. These values are then compared to the vessels’ operating conditions to show if the vessels would currently be able to operate. Ultimately it is found that the extent of damage of the criteria is the greatest limiting factor for this vessel type. Suggestions are made regarding the necessary changes to the boats’ general arrangements and loading conditions in order to meet the damaged stability requirements.

The use of fibre reinforced polymers is rapidly increasing in a range of applications, from aviation to sporting goods. While the outstanding material properties offered by modern composites make them widely applicable they often suffer from brittle, catastrophic failure. Their inherent brittleness limits their application for safety critical applications without large safety margins. This thesis sets out to introduce design principles that introduce a degree of 'pseudo- ductile' failure behaviour to advanced fibre composites. Much of the inspiration for the work comes from looking at the failure processes of natural hierarchical materials. Many of these materials are able to sustain large amounts of damage at different length scales without catastrophic failure, with many of them being essentially ceramics. Nacre, a relatively simple discontinuous laminated material, served as a major inspiration. Three main strategies were employed to reduce the effects of brittle fracture. Ply terminations were used to selectively weaken a laminate allowing one large fracture to be replaced with a number of smaller ones. Thereby giving indication of the laminates failure and significantly increasing the strain to failure over a traditional laminate. Ply perforations, where portions of a ply are cut, were used to weaken a laminate allowing the location of the fracture to be controlled. The third method tailored interlaminar fracture toughness allowing for steady crack propagation where traditional laminates would suffer unstable crack growth. The work introduces three distinct and highly expandable methodologies capable of reducing the limitations of modern composites.

Introduction. To investigate levels of antiovarian autoantibodies in girls and young women with disturbances of menstrual cycle before and during treatment with hormonal therapy. To explain morphological changes in ovarian structure in these patients. Menopause usually occurs approximately at the age of 50. Premature ovarian failure (POF) is a disorder defined as a pathologic termination of menstrual cycle after puberty and before the age of 40. Frequency of this disorder is approximately 1%. Hormonal levels show hypergonadotrophic hypoestrism (FSH more than 40 lU/l). The onset of the disease may be very slow. Menarche and regular menstrual cycles may be followed by menstrual cycle disorders - oligomenorrhoea or secondary amenorrhoea. Sterility or infertility at the reproductive age could be manifestations of the early stage of the disease. One of the possible causes of premature ovarian failure could be an autoimmune process beginning at any time during the reproductive period. Autoimmune damage of the ovarian hormonal production places this disease between the autoimmune endocrinopathies, characterized by direct destruction of the target cells, such as thyroiditis, insulin dependent diabetes and Addison’s disease. Animal models proved that the manifestation of the disease is preceded by complex process that is influenced by genetic, immunologic and environmental factors. Material and methods. Studied group included 39 patients. 18 patients were treated for primary amenorrhoea, 21 for menstrual cycle disorders. Patients included in the study were repeatedly examined at the beginning of the study and after six months during which they were treated by estrogen and gestagen. In all patients we have tested FSH, LH and FSH/LH ratio, presence of antiovarian antibodies. Results were compared with those obtained in control women. 21 antiovarian antibodies positive patients were indicated for laparoscopic biopsy. Bioptic sample was examined using light and electron microscopy. Results. Our treatment with hormonal therapy lead to the reduction of ovarian antigens. In 85% of the cases marked decrease of antiovarian autoantibodies levels was observed, while in 28% of the cases the levels were undetectable. From morphological changes of the bioptic sample enhanced atresia of follicules at different developmental stages was frequently observed. It evoked marked reduction of follicular apparatus up to its complete disappearing. Conclusion. The results of our study and mapping of the antiovarian antibodies positivity support our hypothesis that the antiovarian antibodies positivity corresponds with the clinical symptoms. Appropriate treatment with hormonal replacement therapy minimizes ovarian destruction, preserves ovarian hormonal functions and saves healthy ovarian tissue.
Кафедра акушерства та гінекології

Introduction: To investigate levels of antiovarian autoantibodies in girls and young women with disturbances of menstrual cycle before and during treatment with hormonal therapy. Menopause usually occurs approximately at the age of 50. Premature ovarian failure (POF) is a disorder defined as a pathologic termination of menstrual cycle after puberty and before the age of 40. Frequency of this disorder is approximately 1%. Hormonal levels show hypergonadotrophic hypoestrism (FSH more than 40 IU/l). The onset of the disease may be very slow. Menarche and regular menstrual cycles may be followed by menstrual cycle disorders - oligomenorrhoea or secondary amenorrhoea. Sterility or infertility at the reproductive age could be manifestations of the early stage of the disease. One of the possible causes of premature ovarian failure could be an autoimmune process beginning at any time during the reproductive period. Autoimmune damage of the ovarian hormonal production places this disease between the autoimmune endocrinopathies, characterized by direct destruction of the target cells, such as thyroiditis, insulin dependent diabetes and Addison’s disease. Material and methods: Studied group included 39 patients. 18 patients were treated for primary amenorrhoea, 21 for menstrual cycle disorders. Patients included in the study were repeatedly examined at the beginning of the study and after six months during which they were treated by estrogen and gestagen. In all patients we have tested FSH, LH and FSH/LH ratio, presence of antiovarian antibodies. Results were compared with those obtained in control women. 21 antiovarian antibodies positive patients were indicated for laparoscopic biopsy. Biopticsample was examined using light and electron microscopy. Results: Our treatment with hormonal therapy lead to the reduction of ovarian antigens. In 85% of the cases marked decrease of antiovarian autoantibodies levels was observed, while in 28% of the cases the levels were undetectable. From morphological changes of the bioptic sample enhanced atresia of follicules at different developmental stages was frequently observed. It evoked marked reduction of follicular apparatus up to its complete disappearing. Conclusion: The results of our study and mapping of the antiovarian antibodies positivity support our hypothesis that the antiovarian antibodies positivity corresponds with the clinical symptoms. Appropriate treatment with hormonal replacement therapy minimizes ovarian destruction, preserves ovarian hormonal functions and saves healthy ovarian tissue necessary for future fertility.
Кафедра акушерства та гінекології

This thesis reports a detailed investigation of the micromechanics of agglomerate behaviour under free-fall impact, double (punch) impact and diametrical compression tests using the simulation software TRUBAL. The software is based on the discrete element method (DEM) which incorporates the Newtonian equations of motion and contact mechanics theory to model the interparticle interactions. Four agglomerates have been used: three dense (differing in interface energy and contact density) and one loose. Although the simulated agglomerates are relatively coarse-grained, the results obtained are in good agreement with laboratory test results reported in the literature. The computer simulation results show that, in all three types of test, the loose agglomerate cannot fracture as it is unable to store sufficient elastic energy. Instead, it becomes flattened for low loading-rates and shattered or crushed at higher loading-rates. In impact tests, the dense agglomerates experience only local damage at low impact velocities. Semi-brittle fracture and fragmentation are produced over a range of higher impact velocities and at very high impact velocities shattering occurs. The dense agglomerates fracture in two or three large fragments in the diametrical compression tests. Local damage at the agglomerate-platen interface always occurs prior to fracture and consists of local bond breakage (microcrack formation) and local dislocations (compaction). The fracture process is dynamic and much more complex than that suggested by continuum fracture mechanics theory. Cracks are always initiated from the contact zones and propagate towards the agglomerate centre. Fracture occurs a short time after the start of unloading when a fracture crack "selection" process takes place. The detailed investigation of the agglomerate damage processes includes an examination of the evolution of the fracture surface. Detailed comparisons of the behaviour of the same agglomerate in all three types of test are presented. The particle size distribution curves of the debris are also examined, for both free-fall and double impact tests.

As nuclear waste is being considered for geological deposition, a safe and durable method for sequestering it from the environment is needed. The radiation tolerance of various ceramic compounds was analysed using alpha-decay event molecular dynamics simulations. As the methods traditionally used for damage identification tend to over-predict the amount of damage under nonequilibrium conditions, a method novel for this type of simulation was developed. Using spherical harmonics, the Steinhardt method uses the angles between atoms to build up a fingerprint of the local structure which is translationally and rotationally invariant. This can then be compared to reference structures in order to quantify the amount of each structure type within the simulation cell. Both single and multiple decay event simulations were used to probe the pyrochlore series Gd₂(TixZr₁-x)₂0₇,where 05 x 51, in order to investigate the underlying mechanisms of damage and healing as well as how these mechanisms change with the varying of x. The single decay event simulations outlined the importance of cascade overlap in the accumulation of damage and so high pressure multiple decay event simulations were run. Changes in volume and total energy were compared to structural data from the Steinhardt order parameters in order to gain insight into the atomistic mechanisms responsible for damage and healing. Atmospheric pressure simulations were also run and structural changes consistent with ion bombardment experiments were observed. The results showed that the radiation tolerance of the solid solution increases with increasing Zr content due to the enhanced healing that high ion mobility brings with it. Proposed models for amorphisation kinetics were tested against the structural data from these simulations and a new model was also suggested. Multiple alpha decay simulations were also run on PU02 in order to investigate its tolerance of alpha radiation. The local structure surrounding each atom was analysed using Steinhardt order parameters in order to quantify the damage caused by the alpha decay events. The results of these simulations show that like Gd₂Zr₂0₇, PU0₂ is extremely tolerant of alpha radiation due to its high ion mobility.

Modelling damage in composite materials has played an important role in designing composite structures. Although numerical models for the progressive damage in laminated composites (e.g. transverse cracking, delamination and fibre breakage) have been developed in the literature, there is still a need for further improvement. This thesis aimed at developing damage models suitable for predicting intra-laminar and inter-laminar damage behaviour in fibre-reinforced composite materials. Several approaches such as fracture mechanics and continuum damage mechanics have been adopted for constructing the damage model. Meso-macro-mechanics analysis was performed to gain an insight into the entire damage process up to the final failure of the composite laminate under various conditions. Cohesive elements were placed in the finite element model to simulate the initiation and propagation of matrix crack and delamination in cross-ply laminates. This helped to understand the direct interactions between damage modes, i.e. whether one damage mode would initiate the other damage mode. The formation of a single matrix crack and its propagation across the layer thickness was also revealed. A new cohesive zone/interface element model was developed to consider the effect of through-thickness compressive stress on mode II fracture resistance by introducing friction into the constitutive law of the conventional cohesive zone model. Application of the model to practical problem in composite laminates shows that this model can simulate delamination failure more accurately than the cohesive element in ABAQUS.Damage models based on continuum damage mechanics were proposed for predicting intra-laminar damage and interlaminar damage. Five intra-laminar failure modes, fibre tension, fibre compression, matrix tension, matrix compression and shear failure, were modelled. Damage initiation was predicted based on stress/strain failure criteria and damage evolution law was based on fracture energy dissipation. The nonlinear shear behaviour of the material was considered as well. These models have been implemented into ABAQUS via a user-defined material subroutine and validated against experimental/numerical results available in the literature. The issue related to numerical implementation, e.g. convergence in the softening regime, was also addressed. Numerical simulation of the indentation test on filament-wound pipe was finally conducted and damages generated in the pipe were predicted using the above developed damage models. The predictions show an excellent agreement with experimental observations including load/indentation responses and multiple delaminations shape and size. Attempt was made to detect damage-induced leakage path in the pipe after indentation.