Inverse method for stiffness determination of impact damage in composites

The limited knowledge of stiffness reductions is a major problem in reliably predicting the post-impact strength of composite structures. This work describes development and application of a non-destructive approach for evaluation of the inplane stiffness of impact damage in composites. The approach combines an inverse method linked to a finite element model and non-contact full-field measurements. The material parameters of impact damage are determined by iteratively matching the finite element model to displacement fields measured optically during post-impact loading. A first order, gradient optimization technique coupled with a modified quadratic algorithm is employed. The method is validated on a reference finite element model with axisymmetric damage containing several concentric zones having different properties, and the influence of measurement noise is examined. The approach is applied to in-house experiments with impacted carbon/epoxy laminates to determine their quasi-isotropic mechanical properties in tension and compression. The resulting stiffness distributions are presented and the corresponding nonlinear behaviour of the damage is described. To examine the effect of the type of damage on the mechanical properties a thorough fractographic analysis of the impacted specimens was undertaken. The tensile stiffness is found to be mainly affected by fibre fracture, while the compressive stiffness is strongly linked to delamination buckling. The approach has further been extended for detection and evaluation of multiple impact damage zones at arbitrary locations as well as for stiffness identification of the damage in orthotropic laminates. The accuracy of both extensions is presented and discussed. Finally, possible future applications of the approach are considered

Real-time text translation with using mobile devices

Cílem této práce je návrh a implementace mobilní aplikace pro operační systém Android, která bude sloužit jako real-time překladač textu v obrazu z jednoho jazyka do druhého, přičemž musí podporovat několik světových jazyků a češtinu. Text přečtený z obrazu je přeložen a následně nahradí původní takovým způsobem, aby mu byl po vizuální stránce co nejblíže. Čtenář postupně získává povědomí o oblastech získávání textu z obrazových dat, překladu takto získaných dat, jejich zobrazení na mobilním zařízení a implementace v Android OS. V závěru práce se nachází popis experimentů s různými typy obrazových dat a porovnání s konkurenčními aplikacemi.The aim of this thesis is design and implementation of Android application which will serve as real-time translator from one language to another, including several world languages and Czech. The text obtained from image is translated and replaces the original one with keeping its visual look as much as possible. The reader gradually gets familiar with getting text from images, text translation, displaying text on mobile device and Android OS implementation. In conclusion, the experiments with multiple input images and comparison of existings applications have been done.

Strategy Proposal and Implementation for a Selected Company

Cílem diplomové práce je navrhnout strategii a postup implementace této strategie do vybraného podniku. Teoretická část je věnována vymezení pojmů a metod používaných v praktické části. Praktická část je věnována analýze prostředí podniku za pomocí PEST analýzy, modelu Canvas a SWOT analýzy. Následně je navržena odpovídající strategie a postup její implementace.The goal of this diploma thesis is to propose a strategy and procedury for implementing this strategy into a selected company. The theoretical part is devoted to the definition of terms and methods used in the practival part. The practical part is devoted to analyze the company environment using PEST analysis, Canvas model and SWOT analysis. Subsequently, the appropriate strategy and procedure for its implementation is proposed.115 - Katedra managementuvýborn

Principles of Creation and Set of Demo Applications Running over AndroidOS

Cílem práce je popsat základní principy tvorby aplikací pro operační systém Android. Čtenář se postupně seznamuje se základními stavebními prvky aplikací, včetně vytváření grafického uživatelského rozhraní. Velký důraz je věnován popisu rozhraní pro práci se senzory, na které navazuje kapitola popisující implementaci několika aplikací. Ty právě senzory využívají ke své činnosti. Po přečtení má čtenář základní povědomí o vývoji aplikací pro Android OS.The aim of this thesis is to describe the basic principles of creating applications for Android operating system. The reader gradually gets familiar with the basic building elements of applications, including the creation of a graphical user interface. A great emphasis is placed on the description of sensors interface, which precedes chapter describing implementation of several applications. These applications use sensors for their activity. This thesis gives a basic understanding of developing applications for Android OS.

The Economic Analysis of Tort Law

The Economic Analysis of Tort Law Abstract In the presented thesis I discuss the economic analysis of tort law. The economic analysis of law can be described as the application of economic theory - primarily microeconomics and the basic concepts of welfare economics - to examine the formation, structure, processes, and economic impact of law and legal institutions. The economic analysis of tort law can help understand the impact of tort liability on individuals' behavior, why some areas of human activity are governed by negligence or strict liability, or why, in some cases, the amout of damages is limited. First two chapters describe the economic approach to law as such, they serve as an introduction into this field of study and present the most important methodological approaches. In the first chapter, I also discuss the basic tendencies that have shaped the economic analysis of law throughout its development. Second chapter then discusses some of the fundamental concepts of the economic analysis of law, namely the assumption of rational action, the concept of transaction costs, the efficiency criterion, the importance of the Coase theorem, and the distinction between property rules and liability rules. Following the examination of the concept of economic efficiency, an alternative approach based on the...Ekonomická analýza deliktního práva Abstrakt V předkládané práci se zabývám ekonomickou analýzou deliktního práva. Ekonomickou analýzu práva lze vymezit jako aplikaci ekonomické teorie - primárně mikroekonomie a základních konceptů ekonomie blahobytu - ke studiu vzniku, struktury, procesů a ekonomického dopadu práva a právních institutů. Ekonomická analýza deliktního práva z tohoto pohledu může přispět k porozumění vlivu pravidel deliktní odpovědnosti na chování jednotlivců, proč jsou některé oblasti lidské činnosti podrobeny režimu subjektivní odpovědnosti nebo objektivní odpovědnosti nebo proč v určitých případech je náhrada škody omezená. První dvě kapitoly přibližují ekonomický přístup k právu jako takový, jejich obsahem je uvedení čtenáře do problematiky a představení nejdůležitějších metodologických přístupů. V první kapitole se rovněž zabývám vývojovými tendencemi, které měly vliv na dnešní podobu ekonomické analýzy práva. Předmětem druhé kapitoly je pak diskuze o základních konceptech, se kterými ekonomická analýza pracuje. Podrobněji tedy analyzuji předpoklad racionálního jednání, koncept transakčních nákladů, kritérium efektivnosti a konečně význam Coasova teorému, resp. dichotomie vlastnických a odpovědnostních pravidel. V souvislosti s vymezením kritéria efektivnosti je také představeno...Katedra teorie práva a právních učeníDepartment of Legal Theory and Legal DoctrinesFaculty of LawPrávnická fakult

Analysis of the Supporting Business Infrastructures in the Tritia Region

Cílem bakalářské práce je pomocí PEST analýzy porovnat a vyhodnotit vlivy působící na začínajícího podnikatele v rámci regionu TRITIA ležícím na pohraničí České republiky, Slovenska a Polska. Teoretická část je věnována popisu metod využívaných v praktické části a charakteristice regionu TRITIA. V praktické části jsou analyzovány politické, ekonomické, sociální a technologické vlivy působící na podnikatele v rámci tohoto regionu. Tyto vlivy jsou následně srovnávány a výstupem je zjištění, která země v rámci tohoto regionu má nejlepší podmínky k podnikání.The goal of this bachelor’s thesis is to compare and evaluate influences on entrepreneurs in region TRITIA, located on borders of Czech republic, Slovakia and Poland, by using PEST analysis. The teoretical part is dedicated to the description of methods used in practical part and to describe TRITIA region. The practical part is dedicated to analyse political, economic, social and technological influences affecting entrepreneurs within this region. These influences are compared and the outcome is identification of which country have the best business conditions within this region.115 - Katedra managementuvýborn

Low velocity impact modelling in laminate composite panels with discrete interface elements

A model enabling the detection of damages developing during a low velocity/low energy impact test on laminate composite panels has been elaborated. The ply model is composed of interface type elements to describe matrix cracks and volumic finite elements. This mesh device allows to respect the material orthotropy of the ply and accounts for the discontinuity experimentally observed. Afterwards delaminations are described with interfaces similar to the ones observed with matrix cracks and the coupling between these two damages are established. In the first step, simple stress criteria are used to drive these interface type elements in order to assess the relevance of model principle. Nevertheless, the well known problem of mesh sensitivity of these criteria prevents the use of this model for now as a predictive tool but rather as a qualitative tool. An experimental validation is carried out thanks to impact experimental tests performed by Aboissiere (2003) and a very good match has been found. However, this model could predictivelly be used and would allow to foresee an original method to detect delaminations during an experimental test. This modelling has been successfully tested experimentally and compared to a C-Scan ultrasonic investigation

Ex vivo determination of bone tissue strains for an in vivo mouse tibial loading model

AbstractPrevious studies introduced the digital image correlation (DIC) as a viable technique for measuring bone strain during loading. In this study, we investigated the sensitivity of a DIC system in determining surface strains in a mouse tibia while loaded in compression through the knee joint. Specifically, we examined the effect of speckle distribution, facet size and overlap, initial vertical alignment of the bone into the loading cups, rotation with respect to cameras, and ex vivo loading configurations on the strain contour maps measured with a DIC system.We loaded tibiae of C57BL/6 mice (12 and 18 weeks old male) up to 12N at 8N/min. Images of speckles on the bone surface were recorded at 1N intervals and DIC was used to compute strains. Results showed that speckles must have the correct size and density with respect to the facet size of choice for the strain distribution to be computed and reproducible. Initial alignment of the bone within the loading cups does not influence the strain distribution measured during peak loading, but bones must be placed in front of the camera with the same orientation in order for strains to be comparable. Finally, the ex vivo loading configurations with the tibia attached to the entire mouse, or to the femur and foot, or only to the foot, showed different strain contour maps.This work provides a better understanding of parameters affecting full field strain measurements from DIC in ex vivo murine tibial loading tests

Transient peak-strain matching partially recovers the age-impaired mechanoadaptive cortical bone response

Mechanoadaptation maintains bone mass and architecture; its failure underlies age-related decline in bone strength. It is unclear whether this is due to failure of osteocytes to sense strain, osteoblasts to form bone or insufficient mechanical stimulus. Mechanoadaptation can be restored to aged bone by surgical neurectomy, suggesting that changes in loading history can rescue mechanoadaptation. We use non-biased, whole-bone tibial analyses, along with characterisation of surface strains and ensuing mechanoadaptive responses in mice at a range of ages, to explore whether sufficient load magnitude can activate mechanoadaptation in aged bone. We find that younger mice adapt when imposed strains are lower than in mature and aged bone. Intriguingly, imposition of short-term, high magnitude loading effectively primes cortical but not trabecular bone of aged mice to respond. This response was regionally-matched to highest strains measured by digital image correlation and to osteocytic mechanoactivation. These data indicate that aged bone’s loading response can be partially recovered, non-invasively by transient, focal high strain regions. Our results indicate that old murine bone does respond to load when the loading is of sufficient magnitude, and bones’ age-related adaptation failure may be due to insufficient mechanical stimulus to trigger mechanoadaptation