Dear friends
I need this paper. please if anybody can download that and share it.
title: Analysis of the Action Blast-Induced Vibration Generates on Structure
by Zhi Xin Yan et al., 2011, Advanced Materials Research, 255-260, 1725
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Author: Bruce A. Suprenant | Size: 77 KB | Format:PDF | Quality:Unspecified | Publisher: Concrete Internantional | Year: JANUARY 2004 | pages: 4
The structure can be post-tensioned in one or two
directions. The amount of live load included in the
design load for post-tensioning affects the structure’s
initial and final deflection. When the live load hasn’t
been applied, the slab may have an initial upward
camber that assists the drainage. After the live load is
applied, however, the slab may still be cambered
upward, be flat, or sag. Thus, the behavior of posttensioned
slabs and their effect on balcony drainage
must be discussed with the structural engineer before
deciding whether drainage conditions are acceptable
or a repair is needed.
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Autodesk Simulation is part of Digital Prototyping Autodesk ®. This product contains a set of tools for engineering calculations and analysis is intended for use in mechanical engineering and industrial production. Autodesk Simulation allows design engineers to make informed decisions at the earliest stages of design. Support for various media-aided design and simulation tools developed using the finite element provide producers the opportunity to explore design intent and accurately predict the behavior of the products during the operation. With Autodesk Simulation can test and optimize products before the start of their production. This increases efficiency, reduces the need for physical prototypes, allows to achieve cost savings and reduce the number of errors.
• Support for multi-CAD - Direct associative data exchange with most popular CAD systems.
• Modeling and application of the net - Use of tools and wizards to improve the efficiency and accuracy of finite element analysis.
• Static tension and linear dynamics - Analysis of static and dynamic strength of the products.
• Combined Strength and kinematic analysis - Simulation of multimass systems to support large-scale movement and deformation of strong contact with body parts.
• Analysis of the methods of computational fluid dynamics - The study of thermal characteristics of products, execution of a detailed analysis of fluid flow.
• Complex physical processes - Research multiple physical factors by comparing results of different types of analysis.
Autodesk Simulation software, part of the Autodesk solution for Digital Prototyping, provides a range of mechanical simulation tools to help designers and engineers make decisions earlier in the engineering design process. Support for multi-CAD environments and extensive finite element modeling tools help manufacturers study initial design intent and accurately predict product performance. Companies worldwide use Autodesk ® Simulation Mechanical and Autodesk ® Simulation Multiphysics software to validate and optimize designs before manufacturing-increasing efficiency, minimizing reliance on physical prototypes, reducing costs, and decreasing errors.
Features:
• CAD support-Direct, associative data exchange with most CAD software.
• Modeling and meshing-Create finite element models and meshes using tools and wizards designed to improve productivity and simulation accuracy.
• Video: Static stress and linear dynamics-Study structural response of designs.
• Video: Mechanical event simulation-Enhance design decisions by using multibody dynamics with support for large-scale motion, large deformation, and large strain with body-to-body contact.
• Video: Computational fluid dynamics (CFD) simulation-Study thermal characteristics of designs and perform accurate, detailed fluid flow analysis.
• Video: Multiphysics-Study multiple physical factors acting simultaneously by combining results from different analysis types.
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I found there is not much crack for the new Midas software since Midas release its 2010 version, from Midas Civil 2010 to 2012, Midas Gen, Midas building, etc.
How to design reinforced concrete flat slabs using Finite Element Analysis
Author: Brooker BEng, CEng, MICE, MIStructE | Size: 353 KB | Format:PDF | Quality:Unspecified | Publisher: The Concrete Centre, Riverside House, 4 Meadows Business Park, Station Approach, Blackwater, Camberley, Surrey GU17 9AB | Year: May 2006 | pages: 16 | ISBN: 1-904818-37-4
The relative cost of computer hardware and software has reduced significantly over recent years and many engineers now have access to powerful software such as finite element (FE) analysis packages. However, there is no single source of clear advice on how to correctly analyse and design using this type of software. This guide seeks to introduce FE methods, explain how concrete can
be successfully modelled and how to interpret the results. It will also highlight the benefits, some of the common pitfalls and give guidance on best practice.
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Alot of Engineering Drawings in folder (Very goo Detail)
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A large triaxial investigation of the stress-path-dependent behavior of compacted rockfill
Ming Xu, Erxiang Song and Jinfeng Chen
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Preface
Engineering is not an exact science and, of the many disciplines within engineering,
welding is probably one of the most inexact – rather more of an
art than a science. Much of the decision-making is based on experience and
a ‘gut feel’ for what is or is not acceptable. When the difficulties of shop
floor or site control are taken into account and the occasional vagaries of
the welder and the sometimes inadequate knowledge of supervisory staff
are added, the problems of the practising shop floor engineer can appear
overwhelming. I hope that some of this uncertainty can be dispelled in this
book, which is aimed at those engineers with little or no knowledge of
metallurgy and perhaps only the briefest acquaintance with the welding
processes. It does not purport to be a metallurgical or processes textbook
and I make no apology for this. Having lectured fairly extensively on
welding technology, I have come to realise that most engineers think of
metals as being composed of a large number of small billiard balls held
together by some form of glue. I have attempted to describe the metallurgical
aspects of the aluminium alloys in these terms. I have therefore kept
the contents descriptive and qualitative and have avoided the use of
mathematical expressions to describe the effects of welding.
The book provides a basic understanding of the metallurgical principles
involved in how alloys achieve their strength and how welding can affect
these properties. I have included sections on parent metal storage and preparation
prior to welding and have also described the more frequently encountered
processes. There are recommendations on welding parameters that
may be used as a starting point for the development of a viable welding procedure.
Also included are what I hope will be useful hints and tips to avoid
some of the pitfalls of welding these sometimes problematic materials.
I would like to thank my colleagues at TWI, particularly Bob Spiller,
Derek Patten and Mike Gittos, for their help and encouragement during
the writing of this book – encouragement that mostly took the form of
‘Haven’t you finished it yet?’.Well, here it is. Any errors, inaccuracies or
omissions are mine and mine alone.
-----------------------------------
Contents:
1 Introduction to the welding of aluminium 1
1.1 Introduction 1
1.2 Characteristics of aluminium 4
1.3 Product forms 6
1.4 Welding: a few definitions 6
2 Welding metallurgy 10
2.1 Introduction 10
2.2 Strengthening mechanisms 10
2.3 Aluminium weldability problems 18
2.4 Strength loss due to welding 31
3 Material standards, designations and alloys 35
3.1 Designation criteria 35
3.2 Alloying elements 35
3.3 CEN designation system 36
3.4 Specific alloy metallurgy 40
3.5 Filler metal selection 46
4 Preparation for welding 51
4.1 Introduction 51
4.2 Storage and handling 51
4.3 Plasma-arc cutting 52
4.4 Laser beam cutting 58
4.5 Water jet cutting 63
4.6 Mechanical cutting 64
4.7 Cleaning and degreasing 66
v5 Welding design 69
5.1 Introduction 69
5.2 Access for welding 70
5.3 Welding speed 71
5.4 Welding position 72
5.5 Edge preparation and joint design 72
5.6 Distortion 84
5.7 Rectification of distortion 88
5.8 Fatigue strength of welded joints 89
6 TIG welding 97
6.1 Introduction 97
6.2 Process principles 97
6.3 Mechanised/automatic welding 114
6.4 TIG spot and plug welding 115
7 MIG welding 116
7.1 Introduction 116
7.2 Process principles 116
7.3 Welding consumables 130
7.4 Welding procedures and techniques 135
7.5 Mechanised and robotic welding 141
7.6 Mechanised electro-gas welding 143
7.7 MIG spot welding 144
8 Other welding processes 147
8.1 Introduction 147
8.2 Plasma-arc welding 147
8.3 Laser welding 150
8.4 Electron beam welding 155
8.5 Friction welding 160
9 Resistance welding processes 166
9.1 Introduction 166
9.2 Power sources 167
9.3 Surface condition and preparation 169
9.4 Spot welding 171
9.5 Seam welding 175
9.6 Flash butt welding 176
10 Welding procedure and welder approval 181
10.1 Introduction 181
10.2 Welding procedures 181
10.3 Welder approval 191
11 Weld defects and quality control 199
11.1 Introduction 199
11.2 Defects in arc welding 199
11.3 Non-destructive testing methods 205
Appendix A British and ISO standards related to
welding and aluminium 216
Appendix B Physical, mechanical and chemical
properties at 20°C 226
Appendix C Principal alloy designations: cast products 227
Appendix D Alloy designations: wrought products 228
Bibliography 230
Index 235
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Welding Robots - Technology, System Issues and Applications
Author: J. Norberto Pires, Altino Loureiro and Gunnar Bölmsjo | Size: 2.44 MB | Format:PDF | Quality:Original preprint | Publisher: Springer-Verlag | Year: 2006 | pages: 192 | ISBN: 1-85233-953-5/978-1-85233-953-1
Industrial robots are essential components of today’s factory and even more of the factory of the future. The demand for the use of robots stems from the potential for flexible, intelligent machines that can perform tasks in a repetitive manner at acceptable cost and quality levels. The most active industry in the application of robots is the automobile industry and there is great interest in applying robots to weld and assembly operations, and material handling.
For the sake of competitiveness in modern industries, manual welding must be limited to shorter periods of time because of the required setup time, operator discomfort, safety considerations and cost. Thus, robotic welding is critical to welding automation in many industries. It is estimated as much as 25% of all industrial robots are being used for welding tasks.
Robotic welding is being initiated to satisfy a perceived need for high-quality welds in shorter cycle times. The first generation of robotic welding system was a two-pass weld system, where the first pass is dedicated to learning the seam geometry followed by the actual tracking and welding in the second pass. The second generation of welding systems, on the other hand, track the seam in realtime, performing simultaneously the learning and the seam tracking phases. The third generation of welding systems not only operates in real-time but also learns the rapid changing in seam geometries while operating within unstructured environments. Flexibility was achieved with this third generation of welding systems but at the expenses of a considerable amount of programming work of high skilled people in system’s integration directed to specific applications.
However, availability and agility are additional key issues in modern manufacturing industries, demanding new welding systems incorporating these features as well, revealing in this way the flexibility of the system to the normal operator without the need of extra skills from him.
This book covers up-to-date and relevant work in the area of third generation of robotic welding systems with availability and agility features. The principalwelding processes are reviewed from the point of view of their automation. A distributed system’s approach is followed for the integration of the different components and software of the welding cell and its integration within the global production system. Particular emphasis is given to the availability and agility to the end user. Application examples demonstrating step-by-step the system’s integration design clarify the relevant aspects to the interested reader.
The authors have made a strong-minded effort to set their work in the context of international robotic arc welding research. The mix of specific research issues and the review of broader research approaches make this a particularly welcome contribution.
This book is directed towards readers who are interested in developing robotic welding applications, and in particular to perform system integration. Although this work is presented in the context of arc welding, the issues related to system integration are general in nature and apply to other robotic applications as well.
This book constitutes a valuable source of the kind of information on robotic welding that result of years of experience, making it suitable as well for the decision maker, the application engineer, the researcher, the technician, and the student.
----------------------
Preface
Modern manufacturing faces two main challenges: more quality at lower prices and the need to improve productivity. Those are the requirements to keep manufacturing plants in developed countries, facing competition from the low salary regions of the world. Other very important characteristics of the manufacturing systems are flexibility and agility of the manufacturing process,
since companies need to respond to a very dynamic market with products exhibiting very short life-cycles due to fashion tendencies and worldwide competition. Consequently, manufacturing companies need to respond to market requirements efficiently, keeping their products competitive. This requires a very efficient and controlled manufacturing process, where focus is on automation, computers and software. The final objective is to achieve semi-autonomous systems, i.e., highly automated systems that work requiring only minor operator intervention.
Robotic welding is one of the most successful applications of industrial robot manipulators. In fact, a huge number of products require welding operations in their assembly processes. Despite all the interest, industrial robotic welding evolved only slightly and is far from being a solved technological process, at least in a general way. The welding process is complex, difficult to parameterize and to monitor and control effectively. In fact, most of the welding techniques are not fully understood, namely the effects on the welding joints, and are used based on empirical models obtained by experience under specific conditions. The effects of the welding process on the welded surfaces are currently not fully known. Welding can in most cases impose extremely high temperatures concentrated in small zones.
Physically, that makes the material experience extremely high and localized thermal expansion and contraction cycles, which introduce changes in the materials that may affect its mechanical behavior along with plastic deformation. Those changes must be well understood in order to minimize the effects. The majority of industrial welding applications benefit from the introduction of
robot manipulators, since most of the deficiencies attributed to the human factor is removed with advantages when robots are introduced. This should lead to cheaper products since productivity and quality can be increased, and production costs and manpower can be decreased. Nevertheless, when a robot is added to a welding setup the problems increase in number and in complexity. Robots are still difficult to use and program by regular operators, have limited remote facilities and programming environments, and are controlled using closed systems and limited
software interfaces.
The present book gives a detailed overview of Robotic Welding at the beginning of the twenty-first century. The evolution of robotic welding is presented, showing to the reader what were the biggest steps and developments observed in the last few years. This is presented with the objective of establishing the current state-of-theart in terms of technologies, welding systems, software and sensors. The remaining issues, i.e., the issues that remain open are stated clearly, as a way to motivate the readers to follow the rest of the book which will make contributions to clarify most
of them and help to solve a few.
To do that, a good chapter on “Welding Technology” is presented, describing the most important welding techniques and their potential and requirements for automation using robot manipulators. This chapter includes recent results on robotic welding processes, which can constitute a good source of information and practical examples for readers.
A good revision with current research results on “Sensors for Welding Robots” used on robotic welding is also presented. This includes sensors for seam tracking, quality control and supervision. This chapter includes all system requirements necessary to use those sensors and sensing techniques with actual robot control systems. Hardware and software interfaces are also covered in detail.
A good revision on available welding systems, including hardware and software, clarifying their advantages, and drawbacks is also necessary to give to the reader a clear picture of the area. The book includes a chapter on “Welding Robots: System Issues”, which covers recent state-of-the-art of industrial robotic welding systems currently available in industry and university laboratories.
Finally, a few industrial applications using the presented techniques and systems is presented. The present book includes a chapter on “Robotic Welding: Application Examples”, where a few selected applications are described in detail including aspects related to software, hardware, system integration and industrial exploitation. This chapter uses actual robots, but it is presented in a general way so that the interested reader can easily explore his interests.
Conclusions stating what was presented and what are the next challenges, guiding the reader to what are the next required developments, is presented at the end of the book. A good collection of references is also presented, to enable the reader to explore further from the literature.
J. Norberto Pires, Coimbra, 2005
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