A survey of fracture mechanics applications in the united states

E&wmkg

Fmctun

Mechmics,

1977. Vol. 9. pp. 34I-360.

Pergamon Press.

Printed in Gnat

Britain

A SURVEY OF FRACTURE MECHANICS APPLICATIONS IN THE UNITED STATES T. P. RICH and P. G. TRACY Mechanics Research Laboratory, Army Materials and Mechanics Research Center, Watertown, MA 02172 U.S.A. and D. J. CARTWRIGHT Department of Mechanical Engineering, The University of Southampton, England Abstract-Results are presented in graphical form based upon data collected in a survey of fracture mechanics applications in the United States, which was conducted during the first half of 1975. The participants numbered 235designers, engineers and scientists from industry, govemment and university. The survey considered the field of fracture mechanics in its broadest sense, including all areas of design which involve the various aspects of fracture in solids. The questionnaire used in the survey is given in an Appendix. Continuing input is sought to the established data base on fracture in design, and completed questionnaires should be sent to T. P. Rich.

INTRODUCTION THE SCOPEof the field, fracture mechanics, has rapidly broadened over the past twenty years. What was once thought to be a field narrowly concerned with the mathematical model of linear elastic fracture mechanics is becoming more and more accepted as a field which encompasses all aspects of the mechanisms of fracture in solids. Both research in, and applications of fracture mechanics run the entire spectrum: theoretical to experimental, structures to materials, predicting critical crack sizes to finding flaws of critical dimensions, elastic to plastic, crack initiation to catastrophic fast fracture, etc. Based upon this broad definition, a survey was undertaken during the first half of 1975 to measure both the extent and manner that fracture mechanics concepts and material data developed in research centers and testing laboratories (government, industrial, and university) are currently being employed in engineering design. The results of this survey have been analyzed and are presented in this publication. This information can now be used in the continuing efforts to (a) stimulate the increased interchange of fracture mechanics information between researchers and designers by identifying areas of mutual interest and need; (b) determine areas and direction for future fracture mechanics research by identifying important fracture design problems; and (c) identify educational needs in fracture mechanics for the revision and extension of short course offerings in applied fracture mechanics for design engineers. Because of the broad nature of the survey, this summary of results provides an overall picture of the state of the field which may be of value to both experienced individuals in particular fracture mechanics areas as well as the growing number of newcomers to the field. As a point of background to this project, the survey arose as a result of the authors’ interest in the mechanisms of transfer of fracture mechanics knowledge from research to design applications. An original draft questionnaire was prepared by the authors based upon their research background. It was subsequently revised as a result of a series of interviews which the authors conducted in England with designers from some major industries: pressure vessels, rotating machinery, aircraft structures, engines and rail transportation. After incorporating some further revisions as suggested by various members of the Mechanics Research Laboratory of AMMRC, the questionnaire took its final form and was distributed in early 1975. The questionnaires were distributed to approximately 700 designers, engineers, and scientists across the United States who could be identified as potentially involved with some aspect of the design application of fracture mechanics. Of those, 235 questionnaires were returned and analyzed 341

342

T. P. RICH et al. Table t. (A and B) A.

TYPE OF GROUP FOR WHICH PARTlCiPA~TS RESPONDED

Other 226 9

Subtotal No Replies TOTAL

8.

NUMBER OF PARTiCIP~TS

I

235

INDICATING INVOLVEMENT IN F. FI. APPLICATIVE ROLES (SEE FIG. 1. 5.) INDY.

user

73

Recommender Approver Implementer Researcher

84 60 78 50

GOVT. ::

UNIY. :"4

ii3

:;

47

57

ALL

/ / i

118 151 106 149 154

representing a total of 32% of all people and 46% of all places initially contacted. Specifically, the breakdown of both distribution and rate of return is as follows:

Government University Industry

PEOPLE T, = total contacted Dist~bution Return Rate D, = %T, %D, 21 36 22 30 57 35

PLACES T2 = total contacted ~st~bution Return Rate LJz= %T, %Dz 14 55 25 50 61 42

A development of the profile of the survey participants, along with guidelines utilized in the format of the graphical presentation of results, are given in the next section to assist in interpretation. P~SENTATION

OF RRSULTS

Several questions in the survey were aimed at es~blishing a profile of the participants and their ass~iation with design applications of fracture mechanics. For example, Table 1A shows the dist~bution of group types for which the participants were responding. Table 1B illustrates the number of participants who indicated some involvement in the various roles of design application of fracture mechanics. Specifically, this table presents the responses made by checking a scale graduated from zero (for none) to five (for high), to the following key question (2G) in the survey (Refer to Appendix 2): In your current individual role, indicate your level of involvement in the following aspects of design application of fracture mechanics. (a) Usage of fracture mechanics in engineering design problems through company manuals, data sheets, etc. (b) Recommendation of incorporation of fracture mechanics concepts and parameters into company design procedures. (c) Approval of incorporation of fracture mechanics concepts and parameters into company design procedures. (d) Implementation of new fracture mechanics concepts and parameters into company design procedures. The role of researcher in fracture mechanics was later established to identify those participants whose responses should be evaluated from that viewpoint. Because the survey’s purpose was in fracture mechanics applications, the participant’s response to part (a) of the question was closely scrutinized. In addition, as you will later observe, most of the survey results are based upon a zero to five scale, which corresponds directly to the

A survey of fracture mechanics applications in the United States

343

response scale for each question. These results were then analyzed from two points of reference. First, each result entry is presented as the simple average of all 235 responses to the given question (denoted by ALL). R = (i$ ri)/N

N =235

This serves as a reference base for each entry as a typical “average” viewpoint by someone working in any area of fracture mechanics. Second, each result entry is presented as an average weighted response, where the weighting of each participant’s response is based upon his own indicated involvement in applications usage (denoted by USERS).

(2) where 0 5 wi I 5 from question 2G, part (a). This entry was intended to be more representative of those who actually apply fracture mechanics to design. It is interesting to note that in the following presentation of results, trends shown by the simple average responses agree quite well with those of the weighted averaged USERS. In addition to the functional roles of the participants in design applications, information was gathered as to the “end item” types of design most closely identified with their work. The results of this profile of the survey participants are provided in Table 2. Finally, a completion of the Table 2.

NOTE:

The above totals are not meant to be interpreted as representing total effort in the field; they are intended to give a breakdown of the employment areas of the survey participants.

participant’s profile is given in Fig. 1. Note that in this figure as in the remaining ones, the results are represented graphically with the abscissa corresponding to either the number of participants providing a given response or the normalized average response from a given grouping to a particular question. Other than the two groupings (ALL and USER) already described, Table 3 shows the other participant sortings and weightings performed on certain questions to provide interesting perspectives on selected areas of fracture mechanics applications. Figures l-9 present the results of our analysis of the survey data. The data from each questionnaire were digitized on cards for input into a computer file, sorted, and analyzed on a digital computer and displayed on a graphics tube device. The figures are organized into the following areas of fracture mechanics applications. 1. 2. 3. 4. 5. 6.

Profile of Participants and Their Fracture Activity Area Growth of Fracture Mechanics in Design Use and Selection of Materials General Design Aspects of Fracture Mechanics Slow Cyclic Crack Growth Fast Fracture

344

T. P. RICH ef a(.

Researcher

I

-

-

(Fracture/FlawsConsidered)

Yes

Recommender

No Approver Comparative Importance to ) Other Design Factors

implementer

Much

More -

-

Universf~

Same

~~ernment

User Much

Less -

Industry All

-

%i--k++

0

1

None

2

3

4

Involvement

Participants

a. Design consideration of fracture

b. Participants role in fracture

relatedto the presence of flaws

mechanics

-

applications

impact

Others

Damage Static Strength -

Engine& -

Infinite

Company Specialist -

Life

Consultation

company Data Pages Design Manual

egh None

1

23 None Employment

c. Pa~ici~nt's mechanics

means

Effort d. Participant'sareas of fracture

of fracture

mechanics

applications

applications

Fig. 1. Profile of participants and their fracture activity areas. Table 3.

1

PARTICIPANT TOTALS IN PRIMARY SURVEY SORTING GROUPS GROUP

OESIGN TYPES INCLUDED*

WEIGHTING

ALL

all

None

235

USER

all

On usage

118

INDUSTRY

all

NOI%

111

GOVERNM&NT

all

ffone

66

UNIVERSITY

all

NOM

58

~T~RIAL DEVElOFERS

19

WOW

61

INDUSTRIAL AREAS: ENGlNES

3, 6, 17, 18, 36

On usage

PRESSURE VESSELS

24, 28, 30, 31, 32, 33 36, 44

on usage

AERO

1, 2. 3, 4, 12. 16, 23, 26, 36, 39

on usage

SHIPS STRS

35, 40

on usage

'As identified in Table 2

High

34s

A survey of fracture mechanics applications in the United States Group

Projected 1980 1970-75 196069

1950-59

.,.*.,._. *. f-,-.‘.*. 5v.v.

.**..

2. Users Ail

1.2. Before 2: 1950

E3

~

1

2

3

4

High

0

10

Activity a. Trend in the application of fracture mechanics in design

-

20

30

40

Participants b. Group size of individuals having a major responsibility in fracture mechanics design

Des= Standa*

Su~ic~ent -

Experience

Insufficient -

-

I

Present State

Increase Unchanged -

Associatipn University/ Governma Company Specialist DesF Manual Tert B&S -

Decrease -

Future Trends 20

40

60 Bo 100 120 Participants

c. Size of groups involved with fracture mechanics in design

None

1

2 usage

3

4

High

d. Relative use of information sources on fracture mechanics in design

Fig. 2. Growth of fracture mechanics in design.

7. Nondest~ctive Testing 8. NDT Detection Data 9. Future Considerations for Fracture Mechanics Application To achieve a balanced perspective for interpretation of results, it is as useful to have some insight regarding those whose viewpoints may not be included, as well as those whose viewpoints are. Independent of our good rate of return, some points can be identified which limited the representative nature of our sample. In order to establish a wide spectrum of engineering design people, the distribution list was compiled from various sources: authors of related articles in technical journals from the past twenty years; attendance lists from conferences in related fields such as pressure vessel design, reliability analysis, etc.; data bank of project supervisors and

T. P. RICH et al.

346

None

1

2

3

4

tougher

materials

Activity b. Activity

Fiber

Nonmetals

ConcrS PolymeX CompositZ ClasS CeramE -F

Fiber

In developing

Nonmetals

Concrete Polymers Composites Glass

g

&@.& ~nferrous

Materials Developers Onlv

Alli

Aluminum Alloys

i ‘i

Steels

i None a.

1

2 Usage

3

4

None

High

i

j

h

High

Activity

Relative use of materials engineering design

in

c. Relative

activity

in material

developments

Fracture

Stress

Fracture

Stress -

- Jc COD o!wr CAT R Curve Charpy

V 7 -

-i None

1

2

3

4

High

I None

Usage d.

I

I

I

I

1

I

2

3

4

High

Usage

Relative usage of toughness the selection of materials

tests

in

e. Relative usage of toughness the selection of materials

tests

in

Fig. 3. Use and selection of materials.

principal investigators in related Department of Defense sponsored research and development; referrals from a question in the survey questionna~e which ~rmitted recommenda~on of other approp~ate potenti~ participants. dour this process it was felt that a well-balanced response was obtained from the major companies and government laboratories in the principal design areas of Table 2. However, for smaller companies or for industrial firms which make highly specialized engineering products, or for non-university independent design consultants who would supply technical guidance in the fracture area to smaller companies, our distribution procedure was inadequate. We continue to seek such input to our data base. Finally, one impression which we have developed over the course of our survey, and which directly affects the representative nature of our sample and possibly those of future surveys, is that people are reluctant to provide input to a general fracture mechanics survey when their design situation involves severe operating environments, uncertain material behavior, and critical crack sizes

347

A surveyof fracturemechanicsapplicationsin the UnitedStates

5f users All

Not

at Allr”7

I

0

1

20

’

a0

1

60

’

al

’ ’ loo 120

Participants a. Use of fracture mechanics as a backup technique In design -

0

I xl

I I I 40 60 80 Participants

I I 100 120

Fatigue cl04 Cycles Fatigue ==I04 Cycles Static Strength Combined Cases Miner’s Rule None

b. Use of fracture mechanics as a primary technique in the design prediction of component service life

1

2 3 Involvement

4

High

c. Potential fracture problem areas in design

Tt

-. El

Users All

Ensines Aero Structures

Arrest Fast Fracture

Fast Fracture -

Cycl fc Growth -

Cyclic Growth

Non!* involvement d. Significance of crack growth stages in design

High

None 1234

Involvement

High

e. Significance of crack growlh stages in design

Fig. 4. Generaldesignaspects of fracturemechanics.

which approach the limits of detection capability. Coupled with the human safety aspects of many e~ee~ structures, legal ~pIi~tions from such fracture formation may account for their reluctance to participate. This is u~o~~ate since some of the more interesting problems and aspects of the design application of fracture mechanics lie in these areas. GENERAL DISCUSSION The results of each figure are fairly evident. No generalities will be made, as the authors saw their main role as one of objective data collection, analysis, and presentation. Interpretation of results is largely a function of the viewpoint of the interpreter. It is hoped that the data presented here will be a provoking source of thought and discussion, which will lead to the goals set forth in the introduction.

348

T. P. RICH et al.

Users 5’ All

El

:= El

Users

Test Data

All

.,...................... .55.........f.*.*..,f .......‘..I.........‘. ..,....f.... .*.....*...* *.‘.‘.=‘...‘.**‘.*...5 ..

AK

..I .

.

.

.

.

.

.

.

.

.

.

.

. . ...*

.

Power Law

~ I

None

I

I

I

I

1

2

3

4

1

I High

None

/

I

I

I

1

2

3

4

Usage

I

High

b. Basis for estimating crack growth rates in high cycle fatigue 1b104 CycleSI

a. Basis for estimating crack growth rates in low cycle fatigue (
Full-Scale Test Data

Users .:.

All

El

Fu 11-Seal e

Laboratory Test Data

Test Data Laboratory lest Data

-

AK

Power law

A

Power Law

None

1

2 3 Usage

4

c, Basis for estimating crack growth rates in thermal fatigue

P

~ZZ‘i~.~*~.‘*‘*~.* *.~f*~.~*~~**‘.*‘~.~ ..*....**.. *~,‘.‘*‘.~.‘.~.~,~.*.

f(

-l--J, I

I

I

t

I

None

1

2 3 Usage

4

Hiqh d.

I

,

*

J

High

Basis for estimating crack growth rates under stress corrosion wnditians

Fig. 5. Slow cyclic crack growth.

However, a few specific points are worth noting. We were very pleased with and appreciative of the response received from the survey participants. With this response we have estabhshed an initial data base on the nature of application of fracture mechanics. This base will remain active and any additional input from university, government or industry will be most useful. The questionna~e given in the appendix may be used for this purpose; any completed replies may be forwarded to T. P. Rich at the Army Materials and Mechanics Research Center. In the event of a subsequent survey in future years, the resdts presented in this publication will provide an initial reference point for comparison and identification of changing emphasis in the field. The current data analysis routine has the capability to sort any combination of design types and weight the response to any question of the survey. However, for a more detailed examination of specific areas of the survey in this manner, a larger data base is required. Several questions provided an opportunity for participants to give written information regarding ideas, approaches, and problems not specifically identified in the questionnaire. From these replies, lists were made in three areas of interest as provided in Appendix 1: A. Other considerations and parameters used in the selection of material.

349

A survey of fracturemechanicsapplicationsin the United States

X Users All

El

None

1

2 Usage

3

4

High

b. Statistical methods for estimating. static strength in design for impact damage

K CalculaG Stress Calculat& K ,r Measu remLEFM With Plasticity Correclibn

i

, 1

1

None

-

I

I

2 3 Activity

4

c. influence of consideration in design

I

High

of o~hotropy

LEFM None

1

2 Usage

3

4

High

a. Relative usage of current methods for determining critical crack size

Scatter I :25--

fl :*

22 -

Users All

i

None

;

Significance

d. Significance toughness

;

;

H$h

of scatter on fracture

Scatter k i25-22 -

19 -

19 -

16 -

16 -

13-

13 -

10 -

10 -

7-

7-

4l-

10

I

0

0

Participants

’

10

’ XI

t t M 40 Participants

I 50

t 6x3

f. Future level of acceptable scatter in fracture toughness

e. Present level of acceptable scatter in fracture toughness

Fig. 6. Fastfracture.

B. Areas of insufficient knowledge which has limited the application of fracture mechanics in design. C. Suggested potential topics of interest for a biblio~aphical referencing document which would be continually updated with the growing open literature. Ac~nff~~~gemenfs-~e authorsare gratefulto all of these who made su~estions duringthe preparationof the survey as well as those who took the time to provide thoughtfulresponses. We would like to recognize the efforts of Mr. Frank DeAngelis and the ProgramMaintenanceand Data Entry Branch, AMMRC,duringthe digitizingof survey results and computerizationof the mailingaddresses. The suggestionsand supportof both Mr. R. Shea, Chief, MechanicsResearch Laberatory,AMMRCand Prof. R. Bell, Head, EngineeringMaterialsLaboratories,U~ve~ity of ~ut~pton are highly valued. (Received30 April 1976)

350

T. P. RICH et 01.

Sharp

.‘. E

Inclusions

Engines Pressure Vessels Aero Structure Ship Structure

Sharp Inclusions -

Users All

smooth Inclusions

Smooth Inclusions Surface Pits -

Surface Pits Surface Cracks -

Surface Cracks -

ThruCracks

ThruCracks -

Sharp Voids Smooth Voids -

Sharp Voids 5 mooth Voids -

I None

I

1

I

2 Interest

a. Types of flaws currently

1

I

I

3

4

High

being detected

(IN SERVICE)

1

I

None

1

I

,

3

2 Interest

b. Types of flaws currently

I Hioh ,

4

being detected

-

1

-___-___

-_

(1975)

(PRE-SERVICE)

(Projected

1 None c. Current

I

I

I

I

3 4 2 Involvement employment of NDT techniques 1

J

--

1985)

I 1

Hiah d. Adequacy

I

1

50

loo

I

150

Participants of current NDT capability

Fig. 7. Nondestructive testing.

I

200

I

for flaw detection

351

A survey of fracture mechanics applications in the United States

Confidence Level f%k) a. NDT Detection Capability (in ~BORATORY) (1975)

Confidence Level (46) b. NDT Detection Capability fin SERVICE) (1975)

1.0 NOT TECHNIQUES: fa and b only) x Acoustic emission o Oyes and magnetic analysis I Eddy currents l

Eyeball

D High power optical 7 low power optic& II

ffadi~raphy

+ Scanning electron

microscope

a Ultrasonics l

O.DcOl*

1

I

I

.

l

NOTE: Each data point in a. b. and c represents an individual response.

I

80 90 100 Confidence Level (%I c. Projected requirements in NOT for design engineering purposes (1985)

a

70

Fig. 8. NDT detection data.

352

T. P. RICH et al.

Short for

Lack Adequate Fracture Mechanics Data Others

I None

I

I

I

I

I

1

2 3 Degree

4

Hiqh

a. Limiting factors to the application of fracture mechanics in design

None

Extremely

A Little

A Little

Not at All

Not at All

25

c. Difficulty toughness security

50 Participants

75

2 Interest

3

4

High

b. Areas for future work in the application of fracture mechanics

Extremely

-I

1

loo

in exhanging fracture data because of commercial

-l d. Difficulty fracture security

25

50 Participants

75

in exchanging design applications mechanics because of commercial

Fig. 9. Future considerations for fracture mechanics applications.

100 of

A survey of fracture mechanics applications in the United States

APPENDIX 1. A. Other considemfions

and pammeters

used in materials selection

Analysis of crack paths (composites) Crack branching/arrest Crack growth rate daldn and da/dr Dynamic fracture toughness Krr Equivalent energy Fracture energy of adhesives/interfaces Fracture under combined stresses Hydrogen embrittlement NAG parameter Probabilistic aspects of fracture Prototype testing of flawed structures Slow crack growth Specification of failure criterion parameter in composites Stress corrosion cracking K,== Stress rupture curves B. Areas of insujicient knowledge which has limited the application of I. Crack Growth and Fracture Criteria Ceramics behavior Crack growth through varying thickness Crack initiation Ductile fracture Fatigue integration rule Fracture due to blunt defects Residual stresses Retardation and spectrum loading Stable crack growth Thermal effects Viscoelastic effects in composites 2. Materials Data Ceramics properties Effects of fabrication Nonuniformity of mechanical properties 3. Mechanical Analysis Dynamic effects Laminate effects in the theory of composite fracture Longitudinal cracks in pressure vessels Stress intensity factor solutions for complex geometries Surface cracks Threedimensional elastic and elastic-plastic stress analyses 4. Others Appropriate design methodology Flaw geometry Loads in joints C. Suggested topics for bibliogmphies Adhesives Aero applications Analytical methods Brittle materials Case studies in design Castings Composites and ductile fibers Crack opening displacement (COD) Creep crack growth Creep fracture Critical flaw sizes Cyclic crack growth rates Damage tolerance and life prediction Dynamic toughness Elastic-plastic analyses Elastomer fracture Engines Environmental effects Equivalent energy Finite elements Fractography Fracture origins Fragmentation EFM Vol. 9. No. Z-H

fmcture

mechanics in design

353

354

T. P. RICH ef al.

High loading rate applications High temperature appli~tions Hydrogen embrittlement Inspection methods/NDT J integral and J,,, Joints Limit analysis Microstructural aspects Pipelines and pressure vessles Porous granular media Probabilistic models of fracture Production testing of mill products Quality control R-curves Residual stress Residual strength of full-scale structures Scaling tests on structures Ship structures Strain energy density Stress corrosion cracking Stress intensity factor solutions mixed mode, K,. K,, orthotropic thermal three-dimensional Surface finish effects Sustained load crack growth rates Testing methods Thermal shock Three-Dimensions analyses Transition temperat~es Weldments

APPENDIX 2.(QUESTIONNAIRE) A SURVEY OF FRACTURE MECHANICS APPLICATIONSIN U.S.GOVERNMENT AND INDUSTRY As part of its role as the U.S. Army Material Command lead laboratory in solid mechanics, the Mechanics Research Laboratory of the Army Materials and Mechanics Research Center, Watertown, Massachusetts is conducting a survey on fracture mechanics applications. The purpose of the survey is to measure both the extent and manner that fracture mechanics concepts and material data developed in research centers and testing laboratories (governmen~l, industrial, and university) are currently being employed in engineering design situations (survey p~cipan~). The analysis of the survey rest& wiIl be ~~orrn~ by T. P. Rich of the Mechanics Research Laboratory at AMMRC. The information gathered wiIl be used to prepare a state of the art publication which could serve as a basis for (i) Es~blishment of guide lines and format for increased interchange of applied fracture techniques and data between researchers and design engineers and corresponding development of improved specifications. (ii) Determination of diction and funding for future research in applied fracture mechanics. (iii) Revision and extension of short course offerings in applied fracture mechanics to design engineers. Some of the questions are designed to identify the individual, his organization and his role in design within that organization in order to cast his response to the fracture mechanics questions in a proper perspective However, it is recognized that regardless of their importance to this survey, some questions may seek information which is considered proprietary within some organizations. If any question or part of a question falls within this category to your design operations, please skip to the next one and mark a letter P over the excluded question. In any event, no information gathered from this questionnaire will be directly used and identified with a participant, even if permission is offered. If you wish to take part in the survey, would you please complete the following questionnaire, fold and seal it, and return to the address as printed and franked on th back page. The broad support of American engineers and scientists who are actively engaged in the design u~i~tion of fracture mechanics is needed to make this survey meaningful. The results will be made directly available to all pa~icipants.

355

A survey of fracture mechanicsapplicationsin the United States A SURVEY

OF FRACTURE

MECHANICS

APPLICATIONS

Pleaa comment briefly or check box as appropriate

Name and Address:

Telephone General A.

Areas of Activity

What

are your

pressure

B.

No.

general

ldentifv

the group

survey

areas of engineering

vessel design,

will

ship structures,

or organizational

design

(i.e.. general

structural

element

of your

company

or establishment

Name

I

I

Entire

Companv

I

I

Maior

Division

I

I

I

1

I

1

Individual

I

1

Independent

Fracture

Independent

Designer

1

Is fracture

would

engineering

D.

Are you

E.

Complete activity

testing,

or more

specific

upon

which

your

answers

to this

or Designation

I I

I I

Plant or Laboratorv

I

I

Specialist

I

I

I I

I

Other

Team Specialist Consultant

I

I

fPlease state1

due to the presence

considerations

How

materials

apply.

Group

C.

design,

etc.)

or development

of flaws

or cracks

during

component

?

life a factor

Yes I

you

rate designing

design

familiar

of flaws

the field

the following group

table

in relation

to other

of Fracture

Mechanics

by checking

in the application

as applied

No0

important

to engineering

the scale 0 to 5 appropriately of aspects of fracture

design

factors

in vow

design ?

to indicate

mechanics

to your

the trend

and relative

engineering

design

Prior

to

1950.

above applications

If on the other mechanics,

hand

check

activity

2

3

4

1950

1969 . Now

Projected If your

1

1959

1960. 1970

None 0

Period

- 1980

level has been nil. check

the following

box and skip to section

questions. you

have Indicated

the following

past and/or

box and complete

current

actwitv

the questionnaire.

m the appltcation

of fracture

level of

problems.

Level Time

6 for some concluding

design

Much more cl important

applications?

with

of vow

for the presence

in vow

High 5

T. P. RICH et al.

356 F.

What is your relative methods,

level of employment

and materials

of the following

data to the engineering

means of applicatmn

design problems

NOflf? 0 Derisn

G.

In your current of fracture

H.

indiwdual

If your role is primarily

1

2

4

3

Indicate

role, indicate

mvalved with

the approval

and/or

what

materials

your level of involvement

I” the following

the design usage aspect of fracture impiementat~on

you mainly

r letals

“kg”

1

aspects of design application

of new fracture

application,

who in your organization

design guidelines

?

Materials A.

mechanics concepts,

mechanics.

IS involved with

3.

Manuals

of fracture

of your organization?

%?.ls

Fiber Comporlte Polymeric

Materials

Concrete Others

(Please state)

use. noting

the relative

order of importance

of each.

A survey of fracturemechanics applicationsin the United States B.

What is your relative

level of involvement

with

each of the following? None 1

3

2

High 5

4

I

C.

What is your relative

level of involvement

in detecting

D.

What is your

level of involvement

with

E.

relative

What minimum

each of the following

characteristic

N.D.T.

types of flaws?

techniques?

size of flaws can you detect7

Conditions I”

Is this satisfactory Yes II

Size

Confidence

(in.1

Level (%)

Method

Laboratory

I

In Service

At present

the following

for your purpose? No 0

For the future

(10 years)

Yeso

No 0

T. P. RICH et al. What do you

F.

the next

estimate

as a realistic

requirement

for engineermg

purposes

I” nondestructwe

Size Im.1

4.

A.

Applications Have your

of Fracture applications

to predict

(1)

Confldence

of fracture

service life

to ‘back-up’

using

mechanics materials

in engineering

design

data and fracture

predlctmnr

based upon

How

would

fracture

you

problems

rate your

(%) J

been

mechanics

theory?

relatwe

not at all 1-1

other

mainly

l3.

Level

Mechanics

mainly

(2)

at the end of

I

I

Design

testing

ten years ?

techniques.

such ar full-scale

I]

a lIttIe

level of mvolvement

testing

or service fanlure

r---l

mformatmn?

not at all IJ

m each of the following

types

of design

applicatmn

?

Combined

Cases (Please state)

I Others

C.

What

is your

relative

(Please state)

level of activity

in each of the following

methods

of determining

critical

crack

Hi h 8

None 1 Linear

Elastic

LEFM

with

Crack J

rG?rs

What cases?

Mechanics

(LEFM)

Correction

Factor

Opening

4

3

Displacement

Integral

Strain

D.

Fracture

a Plasticitv

2

SlZeS?

Enerav

Densitv

(Please state)

is your

relative

level of involvement

I

in the determination

I

I

of crack

growth

I

I

I

I

rates for each of the following

A survey of fracture mechanics applications in the United States E.

What is your relative

level of involvement

in the determination

of fatigue 1

0

F.

What relative

importance

do you attach to each of the following

Crack

life using Miners 2

359

Rule? 4

3

aspects of crack growth

5

in your design problems, -

Initiation

Crack Propagation

(Slow)

Crack Propagation

(Fast)

Crack Arrest G.

What importance

do you attach to having low scatter in fracture

toughness data (due to material

0

Ii.

What level of scatter would

you find acceptable

in fracture

2

1

4

3

In the future

What is your current methods

applied

and future

to impact

level of involvement

5

toughness data in your design applications? f

%

r-l f

%

At present

I.

variations)?

in the prediction

(10 years)

of residual static strength

using statistical

damage during operation?

At present In future J.

What is your

relative

effort

each of the following

(10 vears)

to incorporate

d

the orthotropic

nature of materials

None 0 Directional

5.

Influence

on Fracture

of Stress States in Component

Computation

of Stress Intensity

A.

1

2

3

High 5

4

Design

Factors

Aspects of Design Applications What is the relative

level of your fracture

mechanics

effort

in each of the following

N”o” Quality

Service Failure

Analysis

Determination

of Safe Inspection

Design for Impact

3

4

Hgigh

Periods

Static

I

Strenath

I

degree have the following

Lack of a Material’s

Fracture

Mathematics

Lack of Adequate

I

I

I

I

I

Damage during Service factors limited

the application N ne 8

IComplex

2

Life

1 Design for Safe Residual

To what

1

areas?

Control

Desiqn for Infinite

6.

within

Toughness

Computation

Other

in your destign applications

three contexts?

1

mechanics

2

to vow

3

design problems? High 5

4

Data

of Some Fracture

Stress Distribution

Necessary for use with

of fracture

Theorv

I

I

I

I

I

I

I

I

I

I

I

and Stress Historv

a Quantitative

Fracture

Criterion. A Restrictive Fracture

Others

Physical Theorv.

Idealization

in Some Aspect of

Please Identify:

(Please state)

I

I

I

T. P. RICH c.

What is the relative

level of importance

et

at.

of each of the following

sources of informatIon

on fracture

mechanics as

it relates to your design activitv?

Journals

(e.g., Engineering

Reports

(e.g., NLR,

Text

Fracture

CEGB.

Mechanics)

NASA)

Books

Company

Data Sheets/Design

Companv

Specialists

Members

1

of Universities

Research Associations Own

Manuals

and Government (e.g., Welding

,

I

I

I

I

I

,

,

I

Establirhmentsl

Institution!

Past Experience

General

Design Standards

(Please state)

I (1)

D.

How

many

members of your group are involved with

responsibilities

fracture

in design?

1 112131

0

I (21

Is this number

(3)

In the future

Future A.

do you expect

Work in Fracture

About

the number

4

I right

I5

I

I>5

I lnsufficlent

i

I

to Remam

I

same

Decrease

I

I

Mechanics

Indicate

the level of interest

fracture

mechantcs.

Bibliographies

I

Sufficient

Increase

6.

mechanics as a major part of their

of Fracture

or feasiblhtv

Literature

which

in Specific

you attach to each of the following

areas of future

work

Areas

of Interest Increased

Incorporation

of Fracture

Concepts,

Methods,

and Data into Design Standards

8.

How

difficult

would

aspects of commercial

11)

Design applicatiowin

(2)

Materials

fracture

security

be to the successful exchange of

mechanics

Extremely

A IntIe

I

toughness data Extremely

c.

In the event that you would mechanics would

D.

Is there anyone fracture

else wlthm

A little

find bibliographies

you require

of fracture

literature

Not at all

I

Not at all

I

of interest,

what

your organization

who is invoked

mechanics and whose response to this questionnaire

with tiuld

some aspects of design applications prove a useful supplement

Name

you for vour partlcipatton

areas of fracture

to be covered?

Address

Thank

rpecffx

I

m thus survey.

Please return

the completed

querr,onnagre,

of

to your replies?

in