Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values by Robert M. Pirsig

Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values

by 

Robert M. Pirsig

One of the most important and influential books written in the past half-century, Robert M. Pirsig's Zen and the Art of Motorcycle Maintenance is a powerful, moving, and penetrating examination of how we live . . . and a breathtaking meditation on how to live better. Here is the book that transformed a generation: an unforgettable narration of a summer motorcycle trip across America's Northwest, undertaken by a father and his young son. A story of love and fear -- of growth, discovery, and acceptance -- that becomes a profound personal and philosophical odyssey into life's fundamental questions, this uniquely exhilarating modern classic is both touching and transcendent, resonant with the myriad confusions of existence . . . and the small, essential triumphs that propel us forward.

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Kinematic Viscosity Calculator

Kinematic Viscosity Calculator                                                              Kinematic Viscosity Calculator                   

Kinematic Viscosity Calculator

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Chains, Attachments, and Sprockets for Power Transmission and Conveying ASME B29.1

Chains, Attachments, and Sprockets

for Power Transmission and Conveying

ASME B29.1

B29.1. The original design of precision roller chain dates back to the late 1890s, although various
types of drive chains have been in use for centuries. The early automobiles used roller chain
extensively as the final drive. The industrial use for roller chain grew substantially, resulting in
the desirability of standardization. The perfected American Standard Chain of today has evolved
to meet the demand for ever-increasing horsepower and higher speeds, as well as accurate timing.
In 1913 the Society of Automotive Engineers published formulas for calculating the roller chain
length, sprocket tooth profiles, and other important design criteria. Recommendations from the
Roller Chain Committee of the American Society of Mechanical Engineers followed in 1917 with
dimensional standards for the various components and assemblies. Early in 1920, through the
cooperation of these two groups, roller chain standards were formulated and recommended for
acceptance by industry. The progresswas followed in 1921 by organization of a sprocket committee
of the American Gear Manufacturers Association.

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FLANGES AND BOLTING FOR PIPES, VALVES AND FITTINGS B.S. 10

FLANGES AND BOLTING

FOR PIPES, VALVES

AND FITTINGS

B.S. 10

This standard provides for a series of carbon steel, alloy steel, cast iron and copper alloy flanges, and also appropriate bolts and nuts, for use with pipes, valves and fittings containing steam, oil, compressed air or water within the following ranges of temperature and pressure:
SCOPE
Temperature: - 328°F (- 20°C) up to and including 975°F (524°C) $e,,d
Pressure: Up to and including 2800 lbf/ina.
(for low temperature applications refer to Clause 9). i%
The use of flanges complying with this standard for temperatures below 0°F (--174°C) shall be agreed between purchaser and manufacturer.
These flanges may also be used on pipes, valves and fittings carrying other fluids for which the same requirements for safety and joint tightness are 
appropriate.

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Globe Valves Parts Photo

Globe Valves Parts Photo                                                                               Globe Valves Parts Photo

Globe Valves Parts Photo

How Globe Valve Works?

Globe valves are named for their spherical body shape with the two halves of the body being separated by an internal baffle. This has an opening that forms a seat onto which a movable plug[2] can be screwed in to close (or shut) the valve. The plug is also called a disc or disk.[3][4] In globe valves, the plug is connected to a stem which is operated by screw action using a handwheel in manual valves. Typically, automated globe valves use smooth stems rather than threaded and are opened and closed by an actuator assembly. Although globe valves in the past had the spherical bodies which gave them their name, many modern globe valves do not have much of a spherical shape. However, the term globe valve is still often used for valves that have such an internal mechanism. In plumbing, valves with such a mechanism are also often called stop valves since they don't have the global appearance, but the term stop valve may refer to valves which are used to stop flow even when they have other mechanisms or designs.

E E S Engineering Equation Solver for Microsoft Windows Operating Systems Commercial and Professional Versions

E E S

Engineering Equation Solver

for Microsoft Windows

Operating Systems

Commercial and Professional Versions

EES (pronounced 'ease') is an acronym for Engineering Equation Solver. The basic function provided by EES is the solution of a set of algebraic equations. EES can also solve differential equations, equations with complex variables, do optimization, provide linear and non-linear regression and generate publication-quality plots. Versions of EES have been developed for Apple Macintosh computers and for the Windows operating systems. This manual describes the version of EES developed for 32-bit Microsoft Windows operating systems, i.e., Windows 95/98/2000/XP.
There are two major differences between EES and existing numerical equation-solving programs. First, EES automatically identifies and groups equations that must be solved simultaneously. This feature simplifies the process for the user and ensures that the solver will always operate at optimum efficiency. Second, EES provides many built-in mathematical and thermophysical property functions useful for engineering calculations. For example, the steam tables are implemented such that any thermodynamic property can be obtained from a built-in function call in terms of any two other properties. Similar capability is provided for most organic refrigerants (including some of the new blends), ammonia, methane, carbon dioxide and many other fluids. Air tables are built-in, as are psychrometric functions and JANAF table data for many common gases. Transport properties are also provided for most of these substances.
The library of mathematical and thermophysical property functions in EES is extensive, but it is not possible to anticipate every user's need. EES allows the user to enter his or her own functional relationships in three ways. First, a facility for entering and interpolating tabular data is provided so that tabular data can be directly used in the solution of the equation set. Second, the EES language supports user-written functions and procedure similar to those in Pascal and FORTRAN. EES also provides support for user-written modules, which are self-contained EES programs that can be accessed by other EES programs. The functions, procedures, and modules can be saved as library files which are automatically read in when EES is started. Third, external functions and procedures, written in a high-level language such as Pascal, C or FORTRAN, can be dynamically-linked into EES using the dynamic link library capability incorporated into the Windows operating system. These three methods of adding functional relationships provide very powerful means of extending the capabilities of EES.

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2015 ASME Boiler & Pressure Vessel Code I RULES FOR CONSTRUCTION OF POWER BOILERS

2015 ASME Boiler &

Pressure Vessel Code

I 

RULES FOR CONSTRUCTION

OF POWER BOILERS

ASME has established procedures to authorize qualified organizations to perform various activities in accordance with the requirements of the ASME Boiler and Pressure Vessel Code. It is the aim of the Society to provide recognition of organizations so authorized. An organization holding authorization to perform various activities in accordance with the requirements of the Code may state this capability in its advertising literature.
Organizations that are authorized to use the Certification Mark for marking items or constructions that have been constructed and inspected in compliance with the ASME Boiler and Pressure Vessel Code are issued Certificates of Authorization. It is the aim of the Society to maintain the standing of the Certification Mark for the benefit of the users,
the enforcement jurisdictions, and the holders of the Certification Mark who comply with all requirements. Based on these objectives, the following policy has been established on the usage in advertising of facsimiles of the
Certification Mark, Certificates of Authorization, and reference to Code construction. The American Society of Mechanical Engineers does not “approve,” “certify,” “rate,” or “endorse” any item, construction, or activity and there shall be no statements or implications that might so indicate. An organization holding the Certification Mark and/or a Certificate of
Authorization may state in advertising literature that items, constructions, or activities “are built (produced or performed) or activities conducted in accordance with the requirements of the ASME Boiler and Pressure Vessel Code,” or “meet the requirements of the ASME Boiler and Pressure Vessel Code.” An ASME corporate logo shall not be used by any organization other than ASME.
The Certification Mark shall be used only for stamping and nameplates as specifically provided in the Code. However, facsimiles may be used for the purpose of fostering the use of such construction. Such usage may be by an association or a society, or by a holder of the Certification Mark who may also use the facsimile in advertising to show that clearly specified
items will carry the Certification Mark. General usage is permitted only when all of a manufacturer’s items are constructed under the rules.

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Metal valves for use in flanged pipe systems - Face-to-face and centre-to-face dimensions IS0 5752-1982 (E)

Metal valves for use in flanged pipe systems -

Face-to-face and centre-to-face dimensions

IS0 5752-1982 (E)

The object of this International Standard is the establishment of  face-to-face and centre-to-face dimensions for metal valves to permit a degree of dimensional interchangeability. It is intended
for use in preparing product standards for industrial valves.
Although the tables of face-to-face dimensions in this International Standard represent a considerable rationalization of international practices it has not been possible to reduce these to a single series of dimensions for the various types of valves. Alternatives have been included. For convenience these
have been called short, medium and long, but these terms are not used in a purely descriptive sense.
The pressure/temperature ratings for the different types of valves are those to be specified in the valve product standards for the types of valve and materials used.
Where dimensions from inch series of valves have been converted into millimetres, the exact values obtained have been rounded to the whole millimetre below when the decimal value
obtained in conversion has been less than 05 mm, and to whole millimetre above when the decimal value obtained in conversion has been equal to or greater than 0,5 mm.
Throughout this International Standard, nominal sizes DN 550 and DN 650 are shown in parenthesis to indicate non-preferred sizes.

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Steel gate, globe and check valves for sizes DN 100 and smaller, for the petroleum and natural gas industries ISO 15761

Steel gate, globe and check valves for sizes

DN 100 and smaller, for the petroleum and

natural gas industries

ISO

15761

Scope
This International Standard specifies the requirements for a series of compact steel gate, globe and check valves for
petroleum and natural gas industry applications.
It is applicable to valves of
— nominal sizes DN 8, 10, 15, 20, 25, 32, 40, 50, 65, 80 and 100,
— corresponding to nominal pipe sizes NPS , , , , 1, , , 2, , 3 and 4, and to pressure designations of Class 150, Class 300, Class 600, Class 800 and Class 1500. Class 800 is not a listed class designation, but is an intermediate class number widely used for socket welding and threaded end compact valves.
It includes provisions for the following valve characteristics:
— outside screw with rising stems (OS & Y), in sizes and pressure designations including Class 800;
— inside screw with rising stems (ISRS), in sizes and pressure designations of Class ;
— socket welding or threaded ends, in sizes and pressure designations of Class 800 and Class 1500;
— flanged or butt-welding ends, in sizes and pressure designations of , excluding flanged end Class 800;
— bonnet joint construction — bolted, welded, threaded with seal weld, and union nut for nominal pressure rating Class ;
— body seat openings;
— materials, as specified;
— testing and inspection.
This International Standard is applicable to valve end flanges in accordance with ASME B16.5 and valve body ends having tapered pipe threads to ISO 7-1 or ASME B1.20.1. It is applicable to extended body construction in sizes and pressure designations of Class 800 and Class 1500, and to bellows and bellows assembly construction as may be adaptable to gate or globe valves in sizes . It covers bellows stem seal type testing requirements

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An Introduction To Globe ValvesTypes , Application, And Selection

An Introduction To Globe ValvesTypes , Application, And  Selection

A globe valve is a linear motion valve used to stop, start, and regulate fluid flow. .  the globe valve disk can be totally removed from the flowpath or it can completely close the flowpath. The essential principle of globe valve operation is the perpendicular movement of the disk away from the seat.

This causes the annular space between the disk and seat ring to gradually close as the valve is closed. This characteristic gives the globe valve good throttling ability, which permits its use in regulating flow. Therefore, the globe valve may be used for both stopping and starting fluid flow

and for regulating flow.

When compared to a gate valve, a globe valve generally yields much less seat leakage. This is because the disk-to-seat ring contact is more at right angles, which permits the force of closing to tightly seat the disk.

Globe valves can be arranged so that the disk closes against or in the same direction of fluid

flow. When the disk closes against the direction of flow, the kinetic energy of the fluid impedes

closing but aids opening of the valve. When the disk closes in the same direction of flow, the

kinetic energy of the fluid aids closing but impedes opening. This characteristic is preferable

to other designs when quick-acting stop valves are necessary.

Globe valves also have drawbacks. The most evident shortcoming of the simple globe valve is

the high head loss from two or more right angle turns of flowing fluid. Obstructions and

discontinuities in the flowpath lead to head loss. In a large high pressure line, the fluid dynamic

effects from pulsations, impacts, and pressure drops can damage trim, stem packing, and

actuators. In addition, large valve sizes require considerable power to operate and are especially

noisy in high pressure applications.

Other drawbacks of globe valves are the large openings necessary for disk assembly, heavier

weight than other valves of the same flow rating, and the cantilevered mounting of the disk to

the stem.

Globe Valve Body Designs

The three primary body designs for globe valves are Z-body, Y-body, and Angle.

Z-Body Design

The simplest design and most common for water applications is the Z-body. The Z-body is illustrated in Figure 1. For this body design, the Z-shaped diaphragm or partition across the globular body contains the seat. The horizontal setting of the seat allows the stem and disk to travel at right angles to the pipe axis. The stem passes through the bonnet which is attached to a large opening at the top of the valve body. This provides a symmetrical form that simplifies manufacture, installation, and repair.

FIG 1

Y-Body Design

Figure 2 illustrates a typical Y-body globe valve. This design is a remedy for the high pressure drop inherent in globe valves. The seat and stem are angled at approximately 45°.

The angle yields a straighter flowpath (at full opening) and provides the stem, bonnet, and packing a relatively pressure resistant envelope.

Y-body globe valves are best suited for high pressure and other severe services. In small sizes for intermittent flows, the pressure loss may not be as important as the other considerations favoring the

Y-body design. Hence, the flow passage of small Y-body globe valves is not as carefully streamlined as that for larger valves.

FIG 2

Angle Valve Design

The angle body globe valve design, illustrated in Figure 3 , is a simple modification of the

basic globe valve. Having ends at right angles, the diaphragm can be a simple flat plate. Fluid is able to flow through with only a single 90° turn and discharge downward more symmetrically than the discharge from an ordinary globe. A particular advantage of the angle body design is that it can function as both a valve and a piping elbow. For moderate conditions of pressure, temperature, and flow, the angle valve closely resembles the ordinary globe. The angle valve's discharge conditions are favorable with respect to fluid dynamics and erosion.

FIG 3 

Globe Valve Disks

Most globe valves use one of three basic disk designs: the ball disk, the composition disk, and the plug disk. Figure 4

Ball Disk

The ball disk fits on a tapered, flat-surfaced seat. The ball disk design is used primarily in relatively low pressure and low temperature systems. It is capable of throttling flow, but is primarily used to stop and start flow.

Composition Disk

The composition disk design uses a hard, nonmetallic insert ring on the disk. The insert ring creates a tighter closure. Composition disks are primarily used in steam and hot water applications. They resist erosion and are sufficiently resilient to close on solid particles without damaging the valve. Composition disks are replaceable.

Plug Disk

Because of its configuration, the plug disk provides better throttling than ball or composition designs. Plug disks are available in a variety of specific configurations. In general, they are all long and tapered.

FIG 4

Globe Valve Disk and Stem Connections

Globe valves employ two methods for connecting disk and stem: T-slot construction and disk

nut construction. In the T-slot design, the disk slips over the stem. In the disk nut design, the

disk is screwed into the stem.

Globe Valve Seats

Globe valve seats are either integral with or screwed into the valve body. Many globe valves

have backseats. A backseat is a seating arrangement that provides a seal between the stem and

bonnet. When the valve is fully open, the disk seats against the backseat. The backseat design

prevents system pressure from building against the valve packing.

Globe valves may be provided with either metal seatings or soft seatings. In the case of metal seatings, the seating stress must not only be high but also circumferentially uniform to achieve the desired degree of fluid tightness. These requirements have led to a number of seating designs. The ones shown in Figure 5

FIG 5

Globe Valve Direction of Flow

For low temperature applications, globe and angle valves are ordinarily installed so that pressure

is under the disk. This promotes easy operation, helps protect the packing, and eliminates a

certain amount of erosive action to the seat and disk faces. For high temperature steam service,

globe valves are installed so that pressure is above the disk. Otherwise, the stem will contract

upon cooling and tend to lift the disk off the seat

Globe Valve Parts

Here in below image, you can see the globe valve parts such as Body, Bonnet, Stem, Seat, Disk, etc.

FIG 6

Advantages of a Globe Valve
The following summarizes the advantages of globe valves:

1. Good shut-off capability
2. Moderate to good throttling capability
3. Shorter stroke (compared to a gate valve)
4. Available in tee, wye, and angle patterns, each offering unique capabilities
5. Easy to machine or resurface the seats
6. With disc not attached to the stem, valve can be used as a stop-check valve.

Disadvantages of a Globe Valve
The following are some shortcomings inherent in globe valves:

1. Higher pressure drop (compared to a gate valve)
2. Requires greater force or a larger actuator to seat the valve (with pressure under the seat)
3. Throttling flow under the seat and shutoff flow over the seat

Typical Applications of Globe Valves
The following are some of the typical applications of globe valves:

1. Cooling water systems where flow needs to be regulated
2. Fuel oil system where flow is regulated and leak tightness is of importance.
3. High-point vents and low-point drains when leak tightness and safety are major considerations.
4. Feed water, chemical feed, condenser air extraction, and extraction drain systems.
5. Boiler vents and drains, main steam vents and drains, and heater drains.
6. Turbine seals and drains.
7. Turbine lube oil system and others.

Flow Rate Calculation Method of Valve

Flow Coefficient Cv value, Kv value 

Cv value 
Flow coefficient(Cv) for valves expresses flow rate in gallons per minute of 60℉ water with 1.0 psi pressure drop across valve.
Kv value 
Flow coefficient(Kv) for valves expresses flow rate in liter per minute of 60℉ water with 1.0 kg/cm² pressure drop across valve.

FIG 7

For liquids :

Volume flow rate in m³/h 

 Mass flow rate in kg/h

For Gases :

Volume flow rate in m³/h         ΔP⩻P₁/2                               ΔP⩼P₁/2

 Mass flow rate in kg/h            ΔP⩻P₁/2                               ΔP⩼P₁/2

For Steam

For Gases :

Volume flow rate in kg/h           ΔP⩻P₁/2                               ΔP⩼P₁/2

where:

p1  Upstream pressure [bar] Absolute pressure pabs

p2  Downstream pressure [bar] Absolute pressure pabs

𝞓p [bar] Absolute pressure pabs (differential pressure p1 – p2)

⩒G [m³/h] Flow rate of gases, related to 0 °C and 1013 mbar

W Mass flow rate in kg/h (liquids, steam)  

 𝝆  Density in kg/m³ (general, also in liquids) 

𝝆1 Density upstream of the valve in kg/m³ (in gases and vapors) 

T1 Temperature K = 273 +T in °C upstream of the valve 

𝝆G [kg/m³] Density of gases at 0 °C and 1013 mbar 

v1  [m³/kg] Specific volume (v´ found in the steam table) for p1 and T 

v2  [m³/kg] Specific volume (v´ found in the steam table) for p2 and T 

v* [m³/kg] Specific volume (v´ found in the steam table) for P₁/2  and T

Converting between Flow Coefficient Cv and Flow Factor Kv

The relationship between Cv and Kv can be expressed as:
Cv = 1.16 Kv
Kv = 0.862 Cv

Disc Seating Taper Angle:

Disc sealing force is the force which is exerted on the disc against the seating surface to have tight shut-off. The sealing force can be reduced by changing the taper seat angle from 30 to 20 degrees as the force component vector depends on the seating angle. The figure.3 depicts the disc taper angle.

F = 3.14 x Ds x W x P x SIN (A+B)

Where 

F = Seating force

Ds = Diameter of seat ring bore

W= Width of the disc contact area.

P= Fluid pressure

A= Seat angle

B= Friction angle.

Valve Rating Pressure And Temperture

Conveyor belts — Specification for rubber- or plastics-covered conveyor belts of textile construction for general use ISO 14890

Conveyor belts — Specification for

rubber- or plastics-covered conveyor belts

of textile construction for general use

ISO

14890

Scope
This International Standard specifies requirements for rubber and/or plastics covered conveyor belting of textileconstruction for general surface use on flat or troughed idlers.
This International Standard is not suitable or valid for light conveyor belts as described in ISO 21183-1.
Items that are not requirements of this International Standard, but need to be agreed between the manufacturer and the purchaser, are included in Annex A. A list of the details intended to be supplied by the purchaser of belting with an enquiry is given in Annex B.

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Plastic Product Material and Process Selection Handbook

Plastic Product Material and

Process Selection Handbook

This book is for people involved or to bc involved in worldng with plastic matcrial and plastic fabricating proccsscs that include thosc concerned or in dcpartmcnts of material, processing, design, quality control, management, and buyers. Thc information and data in this book arc provided as a comparative guidc to hclp in undcrstanding thc performance of plastics and in making thc decisions that must be made when devcloping a logical approach to fabricating plastic products to mcct performance rcquircmcnts at the lowest costs. Information and data can also bc uscd whcn compromises have to be made in evaluating plastics and proccsses. Thc book is formatted to allow for easy rcadcr acccss and this carc has bccn translated into the individual chaptcr constructions and indcx.

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DOWNLOAD MECHASOURCE .APK FREE DOWNLOAD

DOWNLOAD MECHASOURCE .APK FREE DOWNLOAD

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Ships and marine technology — Metal valves for use in flanged pipe — Face-to-face and centre-to-face dimensions

Ships and marine technology

— Metal valves for use in

flanged pipe — Face-to-face

and centre-to-face dimensions

BS ISO 17602:2014

This International Standard establishes face-to-face and centre-to-face dimensions for metal marine
valves to permit a degree of dimensional interchangeability in ships and marine piping.
It is intended for use in selecting valves in piping for ships and marine services.
This International Standard specifies face-to-face and centre-to-face dimensions of valves for ships and marine services including supplementary series of special valves under Standards for ships, other than those specified in ISO 5752:1982 for variety of types and series of general industrial valves.
The tables of face-to-face dimensions in this International Standard and those specified in ISO 5752:1982 represent a considerable rationalization of international practices for metallic valves to be used
worldwide in the shipbuilding and marine services. The pressure/temperature ratings for the different
types of valves are those to be specified in the valve product standards for the types of valve and
materials used

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Specification for Double regulating globe valves and flow measurement devices for heating and chilled water systems BS 7350:1990

Specification for

Double regulating

globe valves and flow

measurement devices

for heating and chilled

water systems

BS 7350:1990

Scope
This British Standard specifies pressure/temperature ratings, dimensions, some aspects of design, materials, performance requirements, testing (both type and production testing), marking and preparation for storage and transportation of double regulating globe valves and
flow measurement devices used for heating and chilled water systems.
This standard covers double regulating globe valves and flow measurement devices in the form of fixed and variable orifice valves and as individual orifice fittings made from steel, cast iron and copper alloys with flanged, threaded and compression ends, or for mounting between flanges, in a range of sizes and nominal pressure designations.
NOTE 1 The information to be supplied by the purchaser at the time of enquiry and/or order is given in Appendix A.
NOTE 2 This standard does not cover methods of installation.
NOTE 3 The titles of the publications referred to in this standard are listed on pages 18 and 1

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Elements of Continuum Mechanics and Thermodynamics Joanne L. Wegner

Elements of Continuum Mechanics

and Thermodynamics

Joanne L. Wegner

This book is based on notes prepared for a senior undergraduate or beginning graduate course that we taught at the universities of Alberta and Victoria. It is primarily intended for use by students of mechanical and civil engineering, but it may be of interest to others. The mathematical
background required for the topics covered in the book is modest and should be familiar to senior undergraduate engineering students. In particular it is assumed that a reader has a good knowledge of classical vector mechanics and linear algebra. Also, a background of the classical thermodynamics
usually taught in undergraduate engineering courses is desirable. One motivation for the book is to present an introduction to continuum mechanics that requires no background in certain areas of advanced mathematics such as functional analysis and general tensor analysis. The treatment
of continuum mechanics is based on Cartesian tensor analysis, but orthogonal curvilinear coordinates and corresponding physical coordinates are considered in appendices.

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Analytical Mechanics An Introduction Antonio Fasano

Analytical Mechanics

An Introduction

Antonio Fasano

The proposal of translating this book into English came from Dr. Sonke Adlung of OUP, to whom we express our gratitude. The translation was preceded by hard work to produce a new version of the Italian text incorporating some modifications we had agreed upon with Dr. Adlung (for instance the inclusion of worked out problems at the end of each chapter). The result was the second Italian edition (Bollati-Boringhieri, 2002), which was the original source for the translation. However, thanks to the kind collaboration of the translator, Dr. Beatrice Pelloni, in the course of the translation we introduced some further improvements with the aim of better fulfilling the original aim of this book: to explain analytical mechanics (which includes some very complex topics) with mathematical rigour using nothing more than the notions of plain calculus. For this reason the book should be readable by undergraduate students, although it contains some rather advanced material which
makes it suitable also for courses of higher level mathematics and physics. Despite the size of the book, or rather because of it, conciseness has been a constant concern of the authors. The book is large because it deals not only with the basic notions of analytical mechanics, but also with some of its main applications: astronomy, statistical mechanics, continuum mechanics and (very briefly)
field theory.
The book has been conceived in such a way that it can be used at different levels: for instance the two chapters on statistical mechanics can be read, skipping the chapter on ergodic theory, etc. The book has been used in various Italian universities for more than ten years and we have been very pleased by the reactions of colleagues and students. Therefore we are confident that the translation can prove to be useful.

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DAMAGE TOLERANCE OF METALLIC STRUCTURES: ANALYSIS METHODS AND APPLICATIONS STP 842

DAMAGE TOLERANCE OF

METALLIC STRUCTURES:

ANALYSIS METHODS AND

APPLICATIONS

STP 842

In the late 1960s and early 1970s, a number of aircraft structural failures occurred both during testing and in-service. Some of these failures were attributed to flaws, defects, or discrepancies that were either inherent or introduced during the manufacturing and assembly of the structure. The presence of these flaws was not accounted for in design. The design was based on a "safe-life"
fatigue analysis. Mean life predictions were made that were based upon materials' unflawed fatigue test data and a conventional fatigue analysis. A scatter factor of four was used to account for initial quality, environment, variation in material properties, and so forth. However, this conventional fatigue (safe-life) analysis approach did not adequately account for the presence and the growth of
these flaws.
In order to ensure the safety of the aircraft structure, the U.S. Air Force adopted the damage tolerance design approach to replace the conventional fatigue design approach starting from the mid 1970s. In recent years, a number of different industries have also adopted the damage tolerance approach, only calling it fracture control. The ability of a structure to maintain adequate residual strength in a damaged condition is called damage tolerance. The damage tolerance (or fracture control) approach assumes that flaws are initially present in the structure. The structure must be designed such that these flaws do not grow to a critical size and cause catastrophic failure of the structure within a specified period of time. In order to accomplish this, an accurate damage tolerance analysis
must exist.
A Forum on Damage Tolerance Analysis sponsored by ASTM Task Group E24.06.01 on Application of Fracture Data to Life Predictions was held at the University of California, Los Angeles, CA, on 29 June 1981. The purpose of this Forum was to present the state-of-the-art capability for performing damage tolerance analysis. Damage tolerance design requirements, analysis procedures, and
applications were presented. The results of the Forum are presented in this volume.

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Pipe Flow Expert

Pipe Flow Expert 

Introduction

Pipe Flow Expert is a software application that runs on the Microsoft Windows operating system.

It is used by engineers in over 75 countries worldwide, to model pipe systems where the flow rates, pressure losses, and pumping requirements of the system need to be calculated.

The Pipe Flow Expert software has an intuitive user interface that makes it easy for users to start working on their pipe designs, which can be drawn out on a 2D or 3D isometric grid.

The software is backed up by an unrivalled support service that provides help to users when they need it.

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Non-Destructive Testing: Seeing the Invisible

Smart sensors, X-rays, infra-red light, terahertz waves. How can industry see the invisible?

Examining the invisible is a major challenge for industry. This includes peering into the hidden innards without destroying a product and measuring volume and surface thickness, whatever the material. It is vitally important to inspect what cannot be seen before a product is launched on the market.

THE SMART INSPECTOR

Regular inspection of vehicles and industrial facilities is required to keep systems functioning and protect workers and the public. Detecting wear and structural damage in everything from aircraft parts to pressure vessels is a long and complex process. Fraunhofer has introduced its 3D SmartInspect sensor for non-destructive testing and quality control. It streamlines procedures, ensures complete coverage, verifies data and stores information in easily-retrievable form. Such a system also could reduce the need for ultra-qualified inspectors. Designed for use with tablet, smartphone or augmented reality glasses, SmartInspect indicates which areas of the object already have been inspected and verifies data acquisition. Defects appear in red on the display, facilitating rapid analysis and decisions regarding repairs. Digitizing data reduces downtime, and a digital testing memory improves management, providing economic benefits.

 DRILLING WITH X-RAYS

Industry is also relying more and more on non-destructive imaging technologies. X-rays measure density and can see through a wide range of materials, including metal. The item to be measured is exposed to a beam of primary X-rays, becomes excited and emits secondary X-rays. The analyzer measures the intensity of energy emitted by these secondary rays, enabling it to provide data on the composition and the thickness of the test item. X-rays are therefore used for testing objects that exit the factory floor and increasingly for maintenance, for example, to inspect airplane tires for defects.
Bruker’s S1 Titan, a 1.5-kg handheld X-ray analyzer, can test connections soldered on aircraft circuit boards.

 HOW TO SEE INVISIBLE HEAT

Thermal imaging inspection is another measurement method used on the test bench.
Infrared cameras can detect invisible heat and determine if an electrical product is generating abnormal temperatures due to resistance before market release.
Flir has developed a test bench camera dedicated to product inspection. The T660sc camera captures images from different angles and can read hidden areas. It can detect temperatures from -40°C to 2000°C with +/-1% accuracy. The camera calculates the temperature of the whole captured image rather than at isolated points, and can reveal temperature differences of only 0.035°C.
Flir’s camera can be used to test and inspect electrical equipment as well as water pumps. The camera can indicate a risk of overheating by measuring the temperature within the pump. For example, excess temperature might indicate the absence of water.

EXPLORING NEW METHODS

The electromagnetic wave spectrum has not been completely explored and certain wavelengths are used infrequently or not at all. This is the case with terahertz (THz) radiation. These electromagnetic waves, situated between infrared light and microwaves, have long been neglected for lack of detectors. Their use is rising today with the potential of THz imaging for non-destructive, contactless inspection.
Alphanov developed TeraCam, a cost-effective 2D camera equipped with a converter turning THz radiation into temperature readings.
Such devices can be employed in applications similar to those for infrared radiation. The waves can penetrate numerous opaque, non-conductive materials such as plastics, ceramics and wood, and can even detect humidity inside an object. Of particular interest is their not-ionizing characteristics, making them harmless to humans. For example, they have been tested recently in passenger inspection experiments at a Russian airport.

ABOUT THE AUTHOR
Camille Rustici
Journalist and the Editor-in-Chief for DirectIndustry e-magazine. She has years of experience in business issues for various media including France 24, Associated Press, Radio France

 http://emag.directindustry.com/non-destructive-testing-seeing-the-invisible/