Finite element modelling of rate-dependent ratcheting in granular materials

International audienceThe present paper introduces a comprehensive model that is capable of describing the behaviour, under cyclic loading, of the granular materials used in railway tracks and road pavement. Its main thrust is the introduction of the ''Chicago'' law in a continuum approach to account for the ratcheting effects. It also emphasizes rate-dependency as a dissipative mechanism that acts independently or jointly with the ratcheting effect as well as the non-associated plasticity. The numerical procedure is based on the return mapping algorithm, where Newton's method is used to calculate the nonlinear consistency parameter of the flow rule and to obtain a consistent tangent modulus. The model was applied to specific numerical examples including multi-axial and cyclic loading conditions

Experimental and numerical characterization of a mechanical expansion process for thin-walled tubes

Air heat exchangers are made with tubes joined to finned pack. The connection between tubes and fins can be obtained through a mechanical process where an ogive is pushed inside the tube with smaller internal diameter causing its expansion. Residual plastic deformation provides the assembly with the fins. Accurate connection over the whole contact area of the tubes and fins is essential for maximum heat exchange efficiency. The goal of this work is to study and develop a finite element model able to effectively simulate expansion forming, allowing process analysis and, eventually, process optimization. The paper is divided into a first experimental part, where the materials used for the heat exchangers are characterized, and a second numerical part where models have been developed on the basis of the experimental data. The developed models are used to identify the material properties with an inverse method, and then to study the technological process of tube expansion by using a simplified but sufficiently accurate description. The model has proved to be an effective design tool, as it can evaluate the influence of the main parameters on the process and so optimize production according to technological variations

Experimental Investigation and Failure Analysis of Fastened GRP under Bending Using Finite Element Method and Artificial Neural Networks

This paper presents a novel approach that predicts the strength and failure modes of jointed Glass Reinforced Polyester (GRP) samples under bending using Finite Element Method (FEM) and Artificial Neural Network (ANN). The mechanical behavior of fastened glass fiber reinforced plastics composites under bending have been experimentally investigated. Samples were obtained from Amiantit Oman, a manufacturing company operating in Russail Industrial Zone in the Sultanate of Oman. The experimental program involved the conduct of three point bending tests as well as bending tests of mechanically fastened joints under static loads. The experimental results showed that the dimensions of the specimen such as the bending span length, specimen width, and specimen pitch affect GRP strength and stiffness. FEM and ANN results predicted accurately the types of failure modes and their locations along the specimens and compared well with the experimental results

『都城制研究(14)』発刊にあたって

http://purl.org/coar/resource_type/c_184

『古代学』 第11号刊行によせて

departmental bulletin pape

西谷地晴美教授 研究業績目録

departmental bulletin pape

『古代学』第10号刊行に寄せて

http://purl.org/coar/resource_type/c_184

『都城制研究(12)』発刊にあたって

http://purl.org/coar/resource_type/c_184

A Study of Mark Twain\u27s : The Celebrated Jumping Frog of Calaveras County

The Celebrated Jumping Frog of Calaveras County (hereinafter referred as to as JF) is one of Mark Twain\u27s masterpieces. It is not simply his first great success as a writer; it also clearly showcases the author\u27s literary style, particularly his skillful management of the narrative framework. G. Bellamy points out that this framework is one of the reasons JF is considered a masterpiece. This work uses a first-person style in which "I" is used by the storyteller (Twain) to introduce the narrator of the story (Simon Wheeler). "I" has a number of roles in the work: first and foremost, it allows the narrator of the story to relate his tale and, second, it allows the storyteller to describe the appearance and characteristics of the narrator. Twain insisted that it was extremely difficult to tell a story in a humorous way and it required a very polished technique. Wheeler, in this story, is just the right character for this humorous role. In contrast to ordinary criticism which directly describes the subject in hand. Criticizing a fictional example intentionally causes people to associate the example with something real, and produces the same result as criticizing the actual thing itself. Thus, satire is euphemistic criticism. With JF, Twain creates a humorous fable that criticizes the society of the day. Twain has been described not only as a humor writer and satire writer,but also as a social critic and social philosopher

キョウト フカ ノ チホウ トシ カンコウ ニオケル ソーシャルメディア カツヨウ ノ ジレイ ケンキュウ

この研究では、日本の田舎での国外からの観光旅行を増やすことを目的として、京都府北部での観光振興の長所と弱点を見いだすためにパフォーマンス分析を使用した。そして、この解決策と「ジョブエイド」を提案した。本研究によって、日本の田舎観光では、旅行者に対して新しい技術による情報提供がなされていないことが分かった。本研究で提案した「ジョブエイド」は、海外旅行をする者が旅行を計画するための情報を手に入れるために、普及しはじめたソーシャルメディアを用いた新しいマーケティング戦略に焦点を当てている。Seeking to answer the challenge to increase international tourism in rural Japan,this study employs a performance analysis to find strengths and weaknesses of those promoting tourism in northern Kyoto prefecture and then offers solutions and job enhancement aids. The study finds little to no use of new information technologies that today\u27s travelers are using. The main focus of the job aid is on new marketing strategies in social media which is becoming prominent for international travel planning