Prediction of ductile fracture in anisotropic steels for pipeline applications

Large diameter steel pipelines for gas transportation may experience extreme overloads due to external actions such as soil sliding, faults movements, third part interactions. In these scenarios the material undergoes severe plastic strains which locally may reach the fracture limits. Due to the manufacturing process, the steels used in such applications have an anisotropic behavior both for plasticity and fracture. In this paper two steel grades have been characterized in view of anisotropic plastic fracture. Fracture tests have been planned to characterize the fracture behavior under different stress states and in different directions to define the anisotropic sensitivity. Finite element modelling, incorporating an anisotropic plasticity formulation, has been used to calculate the local fracture parameters in the specimens and to define the complete ductile fracture locus. An uncoupled damage evolution law has been finally used to evaluate the fracture limits on real pipelines failed in full scale laboratory tests. The strain to fracture prediction has been verified by local strain measurements on the fractured pipes. The model robustness has been also verified on global parameter predictions, such us the burst pressur

Longitudinal RNA-Seq analysis of acute and chronic neurogenic skeletal muscle atrophy.

Skeletal muscle is a highly adaptable tissue capable of changes in size, contractility, and metabolism according to functional demands. Atrophy is a decline in mass and strength caused by pathologic loss of myofibrillar proteins, and can result from disuse, aging, or denervation caused by injury or peripheral nerve disorders. We provide a high-quality longitudinal RNA-Seq dataset of skeletal muscle from a cohort of adult C57BL/6J male mice subjected to tibial nerve denervation for 0 (baseline), 1, 3, 7, 14, 30, or 90 days. Using an unbiased genomics approach to identify gene expression changes across the entire longitudinal course of muscle atrophy affords the opportunity to (1) establish acute responses to denervation, (2) detect pathways that mediate rapid loss of muscle mass within the first week after denervation, and (3) capture the molecular phenotype of chronically atrophied muscle at a stage when it is largely resistant to recovery

Point-free Ultrametric Spaces and the Category of Fuzzy Subsets

Some attempts to establish a link between point-free geometry and the categorical approach to fuzzy set theory is exposed. In fact, it is possible to find functors between the category of fuzzy sets as defined by Höhle in [4] and a category whose objects are the pointless ultrametric spaces

Flight dynamics and optimal design of a tethered satellite with wings in free molecular flow

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77372/1/AIAA-1993-96-412.pd

Didattica del ragionamento: un esempio di deduzione logica in ambiente Mathematica

Si mostra come, in un ambiente adeguato per il calcolo simbolico, si possano introdurre elementi di programmazione logica, “traducendo” una teoria in un insieme di definizioni di funzioni. Dal punto di vista didattico, tale riduzione della programmazione logica a programmazione funzionale risulta utile per l’ampliamento dell’uso di strumenti informatici all’ambito della logica matematica. Inoltre, un ulteriore obiettivo è quello di facilitare, attraverso tali strumenti, lo sviluppo di competenze non solo nell’ambito del calcolo numerico-algebrico ma anche in quello dell’ informazione di tipo assertivo-logico. Il nostro punto di vista è che nella sperimentazione didattica sia possibile riferirsi alla logica non solo per quanto riguarda il calcolo proposizionale ma anche al suo aspetto deduttivo. E’ necessario evidenziare come il metodo assiomatico sia presente nella vita di tutti i giorni. Nozioni come quelle di “sistema di assiomi” e di “teorema” devono essere interpretate in termini di informazione disponibile, (in generale non completa) circa situazioni della vita reale, e di conseguenze che si possono ricavare a partire da tale informazione

The Michigan aero instructional software project - TODOR meets the world-wide web

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76121/1/AIAA-1998-2790-621.pd

Implementation of a lode angle sensitive yield criterion for numerical modelling of ductile materials in the large strain range

Ductile metallic materials are usually mechanically characterized in the large strain range by means of conventional laboratory tests, namely tensile and torsion test. The identification of the elastic-plastic equivalent stress-strain relation is made by using the widely accepted J2 hypothesis and isotropic behaviour, but results of dedicated tensile and torsion tests on different steel grades showed that it does not seem possible to identify a unique stress-strain curve, as expected on theoretical ground. Curves obtained from dissimilar tests, even though perfectly matching at small plastic strains, start differing significantly from medium strains. Starting from the experimental observations, a general yield surface has been developed based on a well established framework, including beside the J2 invariant also the J3 one. The new yield function has been coded inside a general purpose finite element code by means of dedicated user routines. Implications on the parameters identification and examples of the new yield surface application are discussed in the paper

Application of HTFC powered by LNG on a cruise ship: a case study

The 8th European Fuel Cell Technology & Applications Piero Lunghi Conference - EFC19, aims to bring together academia, research world, industry, public sector to exchange and share their experiences and research results on all aspects of Hydrogen and Fuel Cells technologies and clean energy. It also provides a premier interdisciplinary platform for researchers, practitioners and educators to present and discuss the most recent innovations, trends, and concerns as well as practical challenges encountered and solutions adopted in the fields of Hydrogen and Fuel Cells technologies and clean energy. EFC19 promotes the exchange of ideas on several topics, covering different areas, such as Transport, Infrastructures, Energy Storage, Energy Generation and Cross-cutting& Overarching. In particular, EFC19 covers research activities and studies on material development, manufacturing processes, modelling, diagnostics and process control, system engineering, market and deployment, demonstration and real-world experience. The Proceedings of the Conference collect 220 abstracts of papers presented during the Conference

A BENCHMARK PROBLEM FOR NONLINEAR CONTROL DESIGN

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57785/1/BenchmarkIJRNCproblemIJRNC1998.pd

EXPERIMENTAL IMPLEMENTATION OF INTEGRATOR BACKSTEPPING AND PASSIVE NONLINEAR CONTROLLERS ON THE RTAC TESTBED

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57811/1/BenchmarkIJRNCBuppIJRNC1998.pd