Online English Summarizer tool, free and accurate!
1.Scope
1.1 This test method covers the determination of fracture toughness (KIc) of metallic materials under predominantly linear-elastic, plane-strain conditions using fatigue precracked specimens having a thickness of 1.6 mm (0.063 in.) or greater2 subjected to slowly, or in special (elective) cases rapidly, increasing crack-displacement force.The stress intensity factor, KIc, is measured using the operational procedure (and satisfying all of the validity requirements) specified in Test Method E399, that provides for the measurement of crack-extension resistance at the onset (2% or less) of crack extension and provides operational definitions of crack-tip sharpness, onset of crack extension, and crack-tip plane strain.Significance and Use
5.1 The property KIc determined by this test method characterizes the resistance of a material to fracture in a neutral environment in the presence of a sharp crack under essentially
linear-elastic stress and severe tensile constraint, such that (1) the state of stress near the crack front approaches tritensile plane strain, and (2) the crack-tip plastic zone is small
compared to the crack size, specimen thickness, and ligament ahead of the crack.Terminology
3.1 Definitions:Terminology E1823 is applicable to this test method:
3.1.1 stress-intensity factor, K, KI, KII, KIII [FL-3/2]-- magnitude of the ideal-crack-tip stress field (a stress-field singularity), for a particular mode of crack displacement, in a homogeneous, linear-elastic body.7.1.3 Alternatively, the ratio of yield strength to elastic modulus may be used for selecting a specimen size that will be
adequate for all but the toughest materials When it has been established that 2.5(KIc/?YS)2 is substantially less than the minimum recommended ligament size given
in the preceding table, then a correspondingly smaller specimen can be used.5.1.2 Lower values of KIc can be obtained for materials that
fail by cleavage fracture; for example, ferritic steels in the ductile-to-brittle transition region or below, where the crack front length affects the measurement in a stochastic manner independent of crack front constraint.5.2 This test method can serve the following purposes:
5.2.1 In research and development, to establish in quantitative terms significant to service performance, the effects of metallurgical variables such as composition or heat treatment, or of fabricating operations such as welding or forming, on the fracture toughness of new or existing materials.NOTE 6--For plane-sided specimens the value of BN is equal to the
thickness B.
8.2.2 Specimen width, W, shall be measured, in conformance with the procedure of the annex appropriate to the
specimen configuration, to the nearest 0.03 mm (0.001 in.) or
0.1 %, whichever is larger, at not less than three positions near
the notch location, and the average value recorded.The specification of
K Ic values in relation to a particular application should signify that a fracture control study has been conducted for the component in relation to the expected loading and environment, and in relation to the sensitivity and reliability of the crack detection procedures that are to be applied prior to service and subsequently during the anticipated life.6.4.3 It is not the intent of this test method to exclude the use of other types of gages or gage-fixing devices provided the gage used meets the requirements listed above and provided the gage length does not exceed those limits given in the Annex appropriate to the specimen being tested.Measurements essential to the calculation of K
Ic are specimen thickness, B (and in the case of side-grooved alternative
specimens, BN), crack size, a, and width, W.
8.2.1 Specimen thickness, B (and in the case of sidegrooved alternative specimens, BN), shall be measured before
testing to the nearest 0.03 mm (0.001 in.) or to 0.1 %,
whichever is larger.The second part consists of Annexes that give specific information on displacement gage and loading fixture design, special requirements for individual specimen configurations, and detailed procedures for fatigue precracking.NOTE 3--Alternative W/B ratios different from the recommended ratio
in 7.2.1.1 but still meeting the requirements in 7.2.1 are sometimes useful,
especially for quality control or lot releases purposes, because they allow
a continuous range of product thicknesses to be tested using a discrete
number of specimen widths while still maintaining specimens of full
product thickness.Calculation and Interpretation of Results
9.1 Interpretation of Test Record and Calculation of KIc--In
order to substantiate the validity of a KIc determination, it is
first necessary to calculate a conditional result, KQ, which
involves a construction on the test record, and then to determine whether this result is consistent with the size and yield
strength of the specimen according to 7.1.Therefore it is advisable to
minimize this nonlinearity by preliminarily loading the specimen to a
maximum force corresponding to a stress-intensity factor level not
exceeding that used in the final stage of fatigue cracking, then unloading.3.1.2 plane-strain fracture toughness, KIc [FL-3/2]--the crack-extension resistance under conditions of crack-tip plane strain in Mode I for slow rates of loading under predominantly linear-elastic conditions and negligible plastic-zone adjustment.L = axial direction
R = radial direction
C = circumferential or tangential direction
3.1.4.6 In the case of complex structural shapes, where the grain flow is not uniform, specimen location and crack plane orientation shall reference host product form geometry and be noted on component drawings.Summary of Test Method
4.1 This test method covers the determination of the planestrain fracture toughness (KIc) of metallic materials by increasing-force tests of fatigue precracked specimens.However, because specimen width influences the
amount of crack extension corresponding to the 95 % slope, KIc obtained
with alternative W/B ratios may not agree with those obtained using the
recommended W/B ratio, particularly in products exhibiting a Type I
force-CMOD record (5).The
value of K
Ic from a side-grooved specimen may better represent the
fracture toughness of the material in structural situations where plasticity
is more highly constrained by the crack front geometry such as may be the
case for a surface or corner crack, or by structural details such as keyways,
radii, notches, etc.Side-grooving increases the likelihood of meeting the Pmax/PQ
requirement, enabling a valid KIc to be obtained in products for which it
would not be possible using the recommended specimen.3.1.4.5 For cylindrical sections, where grain flow can be in the longitudinal, radial or circumferential direction, specimen location and crack plane orientation shall reference original cylindrical section geometry such that the L direction is always the axial direction for the L-R-C system, as indicated in Fig.Guide B909 includes additional guidelines for recognizing when residual stresses may be significantly biasing test results, methods for minimizing the effects of residual stress during testing, and guidelines for correction and interpretation of data.Specimen Size, Configurations, and Preparation
7.1 Specimen Size:
7.1.1 In order for a result to be considered valid according to this test method (see also 3.1.2.1), the specimen ligament size (W - a) must be not less than 2.5(KIc/?YS)2, where ?YS is the 0.2 % offset yield strength of the material in the environment and orientation, and at the temperature and loading rate of the test (1, 3, 4).8.3 Loading Rate--For conventional (quasi-static) tests, the
specimen shall be loaded such that the rate of increase of
stress-intensity factor is between 0.55 and 2.75 MPa?m/s (30
and 150 ksi?in./min) during the initial elastic displacement.The force at a 5 % secant offset from the initial slope (corresponding to about 2.0 % apparent crack extension) is established by a specified deviation from the linear portion of the record (1).The validity of the KIc value determined by this test method depends upon the establishment of a sharp-crack condition at
the tip of the fatigue crack in a specimen having a size adequate to ensure predominantly linear-elastic, plane-strain conditions.Indications of residual stress include distortion during specimen machining, results that are specimen configuration dependent, and irregular fatigue precrack growth (either excessive crack front curvature or out-of-plane growth).6.4 Displacement Gage--The displacement gage electrical output represents relative displacement (V) of two precisely located gage positions spanning the crack starter notch mouth.Also, because a shorter
ligament length may hinder resistance curve development, an alternative
specimen with W/B < 2 (allowed only for bend specimens) may pass the
P
max/PQ requirement, while a specimen with the recommended W/B ratio
would fail.The value of KIc from the recommended specimen may
better represent the fracture toughness of the material in structural
situations where surface plasticity and shear lip development is not
constrained such as a through crack in a region of uniform thickness.Side grooving
after precracking beneficially removes a portion of the non-linear crack
front at the ends of the crack front, thus increasing the likelihood of
meeting crack front straightness requirements.For the chevron notch starter configuration,
the fatigue crack shall emerge from the chevron on both
surfaces; furthermore, neither surface crack size measurement
shall differ from the average crack size by more than 15 %, and
their difference shall not exceed 10 % of the average crack size.10.2.4 Fatigue precracking conditions, specifically the
maximum stress-intensity factor, Kmax, stress-intensity factor
range, ?KI, and number of cycles for the final 2.5 % of the
overall crack size, a (size of notch plus fatigue crack extension).A hyphenated code defined in Terminology E1823 is used wherein the letter(s) preceding the hyphen represents the direction normal to the crack plane and the letter(s) following the hyphen represents the anticipated direction of crack extension (see Fig.In most cases the L direction corresponds to the direction of maximum grain flow, but some products such as pancake, disk, or ring forgings can have the R or C directions correspond to the direction of maximum grain flow, depending on the manufacturing method.To establish the suitable crack-tip condition, the stressintensity factor level at which specimen fatigue precracking is
conducted is limited to a relatively low value.Guide B909 provides supplementary guidelines for plane strain fracture toughness testing of aluminum alloy products for which complete stress relief is not practicable.5.2.3 For specifications of acceptance and manufacturing quality control, but only when there is a sound basis for specifying minimum KIc values, and then only if the dimensions of the product are sufficient to provide specimens of the size required for valid KIc determination.The test machine shall have provisions for autographic recording of the force applied to the specimen; or, alternatively, a computer data acquisition system that may be used to record force and CMOD for subsequent analysis. For the straight-through notch
starter configuration, no part of the crack front shall be closer
to the machined starter notch than 0.025W or 1.3 mm (0.050
in.), whichever is larger; furthermore, neither surface crack size
measurement shall differ from the average crack size by more
than 15 % and their difference shall not exceed 10 % of the
average crack size.Hence, the magnitude of their influence on KQ and KIc in
the test specimen may be quite different from that in the original or finish
machined product (see also 5.1.6.)
9.1.2 When a computer data acquisition system is used, the
data reduction program shall determine the same forces (PQ
and P
max) as above.NOTE 1--Plane-strain fracture toughness tests of thinner materials that are sufficiently brittle (see 7.1) can be made using other types of specimens (1).3 There is no standard test method for such thin materials.3.1.4.1 Wrought Products--the fracture toughness of wrought material depends on, among other factors, the orientation and propagation direction of the crack in relation to the material's anisotropy, which depends, in turn, on the principal directions of mechanical working and grain flow.3.1.4.8 Discussion--when products are to be compared on the basis of fracture toughness, it is essential that specimen location and orientation with respect to product characteristic
directions be comparable and that the results not be generalized beyond these limits.The value of K Ic is calculated from this force using equations that have been established by elastic stress analysis of the specimen configurations specified in this test method.Likewise this test method does not apply to high toughness or high tearing-resistance materials whose failure is accompanied by appreciable amounts of plasticity.The effect can be especially significant for specimens removed from as-heat treated or otherwise nonstress relieved stock, from weldments, from complex wrought parts, or from parts with intentionally induced residual stresses.However, for material that
cannot be machined in the final condition, the final treatment
may be carried out after machining provided that the required
dimensions and tolerances on specimen size, shape, and overall
finish are met (see specimen drawings of Figs.To facilitate
fatigue precracking at low stress intensity levels, the suggested
root radius for a straight-through slot terminating in a V-notch
is 0.08 mm (0.003 in.) or less.7.3.2.2 The size of the fatigue crack on each face of the
specimen shall not be less than the larger of 0.025W or 1.3 mm
(0.050 in.) for the straight-through crack starter configuration,
not less than the larger of 0.5D or 1.3 mm (0.050 in.) for the
slot ending in a hole (of diameter D < W/10), and need only
emerge from the chevron starter configuration. 8.2.4 The plane of the fatigue precrack and subsequent 2 %
crack extension (in the central flat fracture area; that is,
excluding surface shear lips) shall be parallel to the plane of the
starter notch to 610?.Thus, in calculating the secant line OP5, the
rotation point of the slope adjustment should be at the
intersection of the line OA with the displacement-axis.7, Types II and III), then
this maximum force is P
Q.
NOTE 7--Slight initial nonlinearity of the test record is frequently
observed, and is to be ignored.The applied loading is superimposed on the residual stresses,
resulting in a total crack tip stress-intensity different from that based solely
on the externally applied forces.If P
max/PQ does exceed 1.10, then the test is not a valid
K
Ic test and the user is referred to Test Method E1820 on
elastic-plastic fracture toughness.Notwithstanding these variations, however, KIc is believed to represent a lower limiting value of fracture toughness (for 2 % apparent crack extension) in the environment and at the speed and temperature of the test.5.1.4 Cyclic forces can cause crack extension at KI values less than K Ic. Crack extension under cyclic or sustained forces (as by stress corrosion cracking or creep crack growth) can be influenced by temperature and environment.5.2.2 In service evaluation, to establish the suitability of a material for a specific application for which the stress conditions are prescribed and for which maximum flaw sizes can be established with confidence.6.2 Fatigue Precracking Machine--When possible, the calibration of the fatigue machine and force-indicating device shall be verified statically in accordance with Practices E4.6.4.1 The specimen shall be provided with a pair of accurately machined knife edges to support the gage arms and serve as displacement reference points.The required linearity shall correspond to a maximum deviation of 0.003 mm (0.0001 in.) of the individual displacement readings from a least-squares-best-fit straight line through the data.If the form of the material available is such that it is not possible to obtain a test specimen with ligament size equal to or greater than 2.5(KIc/?YS)2, then it is not possible to make a valid KIc measurement according to this test method.7.2.2.1 Alternative Side-Grooved Specimens--For the compact C(T) and the bend SE(B) specimen configurations sidegrooving is allowed as an alternative to plain-sided specimens.As a result, the KIc value from a side-grooved specimen is expected
to be lower than the K
Ic obtained from the recommended specimen,
particularly for thin products or products exhibiting Type I behavior.The increased constraint also can lead to
increased likelihood of material delamination, for instance, in the plane of
the specimen, which could lead to test results different from those
obtained from plane-sided specimens.However, the results of several studies (6) indicate that KIc
from side-grooved specimens is zero to 10 % less than that of plain-sided
specimens, the difference increasing with increasing material toughness.8.2.3 Specimen crack size, a, shall be measured after
fracture to the nearest 0.5 % at mid-thickness and the two
quarter-thickness points (based on B for plain-sided specimens
and B
N for side-grooved specimens).If this ratio does not exceed 1.10, proceed to calculate KQ
as described in the Annex appropriate to the specimen configuration.10.2 The following information shall be additionally reported for each specimen tested:
10.2.1 Characterization of the material (alloy code or chemistry and metallurgical condition) and product form (sheet,
plate, bar, forging, casting, and so forth) tested.3.1.3 crack mouth opening displacement (CMOD), Vm [L]-- crack opening displacement resulting from the total deformation (elastic plus plastic), measured under force at the location on a crack surface that has the largest displacement per unit force.1(a), the T-L specimen fracture plane normal is in the width direction of a plate and the expected direction of crack propagation is coincident with the direction of maximum grain flow (or longitudinal) direction of the plate.The designation L-TS, for example, indicates the crack plane to be perpendicular to the principal deformation (L) direction, and the expected fracture direction to be intermediate between T and S. The designation TS-L means that the crack plane is perpendicular to a direction intermediate between T and S, and the expected fracture direction is in the L direction.5.1.3 The value of K Ic obtained by this test method may be used to estimate the relation between failure stress and crack size for a material in service wherein the conditions of high constraint described above would be expected.6.3 Loading Fixtures--Fixtures suitable for loading the specified specimen configurations are shown in the Annexes.The verification procedure shall be performed three times, removing and reinstalling the gage in the calibration fixture after each run.The gage shall be verified during the time the gage is in use at time intervals defined by established quality assurance practices.The specimen must also be of sufficient thickness, B, to satisfy the specimen proportions in 7.2.1 or 7.2.1.1 and meet the P max/PQ requirement in 9.1.3.7.1.2 The initial selection of specimen size for a valid KIc measurement is often based on an estimated value of K Ic for the material.7.2.1 Specimen Proportions--Crack size, a, is nominally
between 0.45 and 0.55 times the width, W. Bend specimens can
have a width to thickness, W/B, ratio of 1 <= W/B <= 4.Conversely, an alternative specimen with W/B >2 (allowed in
both tension and bend specimens) may fail the Pmax/PQ requirement,
while a specimen with the recommended W/B would pass.Precracking prior to the sidegrooving operation is recommended to produce nearly straight
fatigue precrack fronts.For side-grooved specimens, the plane
of the fatigue precrack and subsequent 2% crack extension
shall be within the root of the side-groove.Loading rates corresponding to these stress-intensity factor
rates are given in the Annex appropriate to the specimen being
tested.The procedure is as
follows:
9.1.1 When an autographic recorder is used, the conditional
value P
Q is determined by drawing the secant line OP5, (see
Fig.9.1.3 The ratio P
max/PQ, where Pmax is the maximum force
the specimen was able to sustain (see 8.4.1), shall be calculated.Expressions for calculating KQ are given in the
Annexes for each specified specimen configuration.For cylindrical
sections, where grain flow can be in the longitudinal, radial or
circumferential direction, the direction of maximum grain flow
shall be reported when the direction is known (see 3.1.4).10.2.3 Specimen width (depth), W.
10.2.3.1 Loading hole offset, X, for the arc-shaped tension
specimen.10.2.5 Crack size measurements, after fracture, at midthickness and the two quarter-thickness positions on the crack
front, as well as at the intersection of the crack front with the
specimen surface.Additional annexes are provided that give specific procedures for beryllium and rapid-force testing.3.1.2.1 See also definitions of crack-extension resistance, crack-tip plane strain, and mode in Terminology E1823.In addition, product form shall be identified (for example, straight-rolled plate, cross-rolled plate, pancake forging, and so forth) along with material condition (for example, annealed, solution treated plus aged, and so forth).Force versus crack-mouth opening displacement (CMOD) is recorded either autographically or digitally.4.2 The specimen size required for test validity increases as the square of the material's toughness-to-yield strength ratio.Background information concerning the basis for development of this test method in terms of linear elastic fracture mechanics may be found in Refs (1) and (2).5.1.5 Plane-strain fracture toughness testing is unusual in that there can be no advance assurance that a valid K Ic will be determined in a particular test.Therefore, compliance with the specified validity criteria of this test method is essential.Careful alignment of the specimen and fixturing is necessary to encourage straight fatigue cracks.A recommended design for a self-supporting, releasable displacement gage is shown in Fig.6.4.2 Each gage shall be verified for linearity using an extensometer calibrator or other suitable device.Readings shall be taken at ten equally spaced intervals over the working range of the gage (see Annex A1).7.2.1.1 Recommended Proportions--It is recommended that
the thickness, B, is nominally one-half the specimen width, W
(that is, W/B = 2).7.3 Specimen Preparation--All specimens shall be tested in
the finally heat-treated, mechanically-worked, and
environmentally-conditioned state.A7.1), and that full account is taken of the effects of
specimen size on metallurgical condition induced by certain
heat treatment procedures; for example, water quenching of
steels.Fatigue cycling is continued until
a crack is produced that satisfies the requirements of 7.3.2.1
and 7.3.2.2 that follow.8.2 Specimen Measurement--Specimen dimensions shall
conform to the drawings of Figs.For side-grooved specimens, BN
shall be measured at the root of the notch and B adjacent the
notch.8.4 Test Record--A record shall be made of the output of the
force-sensing transducer versus the output of the displacement
gage.If an
autographic recorder is used, it shall be adjusted such that the
slope of the initial portion of the force-CMOD record is
between 0.7 and 1.5.Alternatively, if a computer data acquisition system is used, it shall be programmed to capture enough
data to permit the calculations of Section 9.7) through the origin (point O) of the test record with slope
(P/V)5 equal to 0.95(P/V)o, where (P/V)o is the slope of the
tangent OA to the initial linear portion of the record (Note 7).The point O
lies on the best fit line through the initial linear portion of the
record and at the intersection of the best fit line with the
displacement-axis.NOTE 8--Residual stresses can adversely affect the indicated KQ and KIc
values.In addition, residual stresses will likely
redistribute during machining when the specimen is extracted from the
host material.9.1.4 The value 2.5(KQ/?YS)2, where ?YS is the 0.2 % offset
yield strength in tension (see Test Methods E8/E8M), shall be
calculated.9.1.5 If the test result fails to meet the requirements of 9.1.3
or 9.1.4, or both, it will be necessary to use a larger specimen
to determine K
Ic.
10.As an example, a test result obtained using the compact
specimen (see Annex A4) might be designated as follows:
C(T)(S-T).3.1.1.1 K is a function of applied force and test specimen size, geometry, and crack size, and has the dimensions of force times length-3/2.The user shall be referred to product specifications for detailed processing information.3.1.4.2 For rectangular sections, the reference directions are identified as in Fig.L = direction of principal deformation (maximum grain flow)
T = direction of least deformation
S = third orthogonal direction
3.1.4.3 Using the two-letter code, the first letter designates the direction normal to the crack plane, and the second letter the expected direction of crack propagation.3.1.4.4 For specimens tilted in respect to two of the reference axes as in Fig.3.1.4.7 Non-Wrought Products--for non-wrought products, specimen location and crack plane orientation shall be defined on the part drawing.The result of a fracture toughness test from a non-wrought product shall not carry an orientation designation.5.1.1 Variation in the value of KIc can be expected within the allowable range of specimen proportions, a/W and W/B.Therefore, when K Ic is applied to the design of service components, differences between laboratory test and field conditions shall be considered.5.1.6 Residual stresses can adversely affect the indicated
K Q and KIc values.Apparatus
6.1 Testing Machine and Force Measurement--The calibration of the testing machine shall be verified in accordance with Practices E4.The fixturing shall be such that the stress distribution is uniform across the specimen thickness and symmetrical about the plane of the prospective crack.The fixtures are designed to minimize friction contributions to the measured force.The knife edges may be machined integral with the specimen as shown in Figs.For testing at rates other than quasi-static see Annex A10, Rapid Force Testing.Meeting the ligament size and Pmax/PQ requirements cannot be assured in advance.Thus, specimen dimensions shall be conservatively selected for the first test in a series.As an example, a specimen with the recommended proportion W/B = 2 would tend to yield a lower KIc than a
specimen with an alternative proportion W/B = 4.These alternative specimens shall have the same crack
length-to-specimen width ratio as the standard specimen.The total thickness reduction shall not exceed 0.25 B. A total
reduction of 0.20 B has been found to work well (6) for many
materials and is recommended (10% per side).BN is the minimum thickness measured
at the roots of the side grooves.The increased constraint promotes a more
uniform stress state along the crack front and inhibits shear lip development.NOTE 5--No interlaboratory 'round robin' test program has yet been
conducted to compare the performance of plain-sided and side-grooved
specimens.7.2.2.2 For lot acceptance testing, side-grooved specimens
shall not be used unless specifically allowed by the product
specification or by agreement between producer and user.7.3.1 Fatigue Crack Starter Notch--Three fatigue crack
starter notch configurations are shown in Fig.Care shall be taken to ensure
that this stress raiser is so located that the crack plane
orientation requirements of 8.2.4 can be met.7.3.2 Fatigue Precracking--Fatigue precracking procedures
are described in Annex A8.For plain-sided specimens, B shall be
measured adjacent the notch.For rapid-force tests, loading rates are to be as specified
in Annex A10. 7, Type
I), then P5 is PQ; if, however, there is a maximum force
preceding P5 which exceeds it (Fig.If this quantity is less than the specimen ligament
size, W-a then KQ is equal to KIc.10.2.3.2 Outer and inner radii, r2 and r1, for arc-shaped
specimens.10.2.9 Force-versus-crack mouth opening displacement
(CMOD) record and associated calculations.Details of test apparatus, specimen configuration, and experimental procedure are given in the Annexes.3.1.4 crack plane orientation--identification of the plane and direction of crack extension in relation to the characteristic directions of the product.Details of the test specimens and experimental procedures are given in the Annexes.The present test method does not apply to such materials and the user is referred to Test Method E1921 and E1820.If the machine cannot be calibrated and verified statically, the applied force shall otherwise be known to 62.5 %.Exact and positive positioning of the gage on the specimen is essential, yet the gage must be released without damage when he specimen breaks.Displacement gage and knife-edge designs shall provide for free rotation of the points of contact between the gage and the specimen.The effective gage length is established by the points of contact between the screw and the hole threads.A No. 2 screw will permit the use of attachable knife edges for specimens having W > 25 mm (1.0 in.).The resolution of the calibrator at each displacement interval shall be within 0.00051 mm (0.000020 in.).The absolute accuracy, as such, is not important in this application, since the test method is concerned with relative changes in displacement rather than absolute values (see 9.1).Verification of gage calibration shall be performed at the temperature of test 65.6?C (10?F).Commercial gages are typically verified annually.7.2 Specimen Configurations--Recommended specimen
configurations are shown in Figs.7.2.2 Alternative Specimens--In certain cases it may be
necessary or desirable to use specimens having W/B ratios
other than that specified in 7.2.1.Alternative W/B ratios and side-grooved specimens are allowed as specified in 7.2.1.1 and
7.2.2.1.The root of the side groove
shall be located along the specimen centerline.NOTE 4-- Side-grooves increase the level of constraint with respect to
the recommended specimen.This is
often true for cast parts and those for which thermo-mechanical working
is part of the heat treating cycle.The within-laboratory repeatability was determined according to the
conditions in Terminology E456 and the results are presented in 11.3.8.4.1 The test shall be continued until the specimen can
sustain no further increase in applied force.The maximum
force (Pmax) shall be noted and recorded.In practice the origin (point O) is not necessarily at the
intersection of the displacement- and force-axes.The
force P
Q is then defined as follows: if the force at every point
on the record which precedes P5 is lower than P5 (Fig.Report
10.1 The specimen configuration code shown on the specimen drawing (in the appropriate Annex) shall be reported.The first letter (C) indicates the specimen to be a
compact configuration.10.2.2 Specimen thickness, B, for plain-sided configurations.The first part gives general recommendations and requirements for KIc testing.1.3 General information and requirements common to all specimen configurations
3.The same system is used for sheet, extrusions, and forgings with nonsymmetrical grain flow.NOTE 2--The same system is useful for extruded or forged parts having circular cross section.3.2 Definitions of Terms Specific to This Standard:
3.2.1 stress-intensity factor rate, K?(FL-3/2 t-1)--change in stress-intensity factor, K, per unit time.Therefore a range of proportional specimens is provided.KIc may also be expected to rise with increasing ligament size.Guidance on testing elastic-plastic materials is given in Test Method E1820.The gage's strain gage
bridge arrangement is also shown in Fig.A suggested design for attachable knife edges is shown in Fig.For the design shown, the major diameter of the screw is used in setting this gage length.Likewise, the crack size, a, should be
nominally equal to one-half the width, W (that is a/W = 1/2).6 is a
schematic showing an example cross section of an alternative
side grooved specimen.For the chevron form of notch,
the suggested root radius is 0.25 mm (0.010 in.) or less.For the
slot ending in a drilled hole, it is necessary to provide a sharp
stress raiser at the end of the hole.However, it is important to establish the
initial slope of the record with high precision. This
code shall be followed with the loading code (T for tension, B
for bending) and the code for crack plane orientation (see
3.1.4).The latter two codes shall appear in separate parentheses.The first of the two letters in the last bracket
(S) indicates the normal to the crack plane to be normal to the
direction of principal deformation.The second of these letters
(T) indicates the intended direction of crack extension to be
parallel with the direction of least deformation.For side-grooved specimens, B, BN and (B. BN)1/2.10.2.7 Relative humidity as determined by Test Method
E337.1.2 This test method is divided into two parts.Orientation of the crack plane shall be identified wherever possible.1(b), which give examples for rolled plate.1(b), crack plane orientation is identified by a three-letter code.1(c), regardless of the maximum grain flow.As such, the direction of maximum grain flow shall be reported when the direction is known.Force is applied either in tension or three-point bending.2 and described in Annex A1.2 and 3, or they may be separate pieces affixed to the specimen.This design features a knife edge spacing of 5 mm (0.2 in.).Tension
specimen configurations can be 2 <= W/B <= 4.However, side grooving
may also remove material that influences service performance.Specimens shall normally
be machined in this final state. 7.3.2.1 Crack size (total size of crack starter plus fatigue
crack) shall be between 0.45W and 0.55W.General Procedure
8.1 Number of Tests--It is recommended that triplicate tests,
minimum, be made for each material condition.The average of these three
measurements shall be taken as the crack size, a. The difference between any two of the three crack size measurements
shall not exceed 10 % of the average.8.2.5 There shall be no evidence of multiple cracking (that
is, more than one crack) (7).The algorithms for doing this are discretionary.Otherwise, the test is not a valid K
Ic test.The second letter (T) denotes the
loading as tension.I (change in stressintensity factor per unit time) (2).10.2.10 Yield strength as determined by Test Methods
E8/E8M.1(a) and Fig.For example, in Fig.Note that this is a geometry based system.A3.1-A6.1 and Fig.Any included
angle less than 90?The root radius shall be 0.5 6
0.2 mm (0.02 6 0.01 in.).Fig.A3.1-A6.1 and
Fig.A3.1-A6.1 and Fig.The crack size shall be
measured also at each surface.The data acquisition system shall be set such that not less
than 50 % of full range is used for the test record.10.2.8 Loading rate in terms of K? 1).4.5.6.2.4.7.A7.1.is allowed.5.8.A7.1.9.10.2.6 Test temperature.
Summarize English and Arabic text using the statistical algorithm and sorting sentences based on its importance
You can download the summary result with one of any available formats such as PDF,DOCX and TXT
ٌYou can share the summary link easily, we keep the summary on the website for future reference,except for private summaries.
We are working on adding new features to make summarization more easy and accurate
رجو من جميع متابعين والمشاهدين الاشتراك في القناة وتفعيل الجرس من اجل ان تعم الفائدة على الجميع. سات...
ً رد ماكس إيبرل، المدير الرياضي الجديد لبايرن ميونخ، على تصريحات نيك هوسيه، وكيل أعمال الظهير الأيسر...
Experimental investigations were conducted to examine the influence of surface enhancement on crysta...
مقدمة البحث: تأتى البيئات التفاعمية التعميمية كمف ضمنيا المنصات التعميمية اإللكتركنية في ن عمى تكظي...
تشير الموجة النسوية الأولى إلى نشاطات الحركة النسوية الممتدة خلال القرن الثامن عشر. والتي جاءت كاستج...
Digitalization affects international trade on many levels, by transforming the way in which goods a...
In telecommunications and computer networking, connection-oriented communication is a communication ...
١ - أَن هَذِه الْمذَاهب الْأَرْبَعَة الْمُدَوَّنَة قد اجْتمعت الْأمة أَو من يعْتد بِهِ مِنْهَا على ج...
The drug concentration of the second drug layer is higher than the first layer, and therefore ascend...
تدقيق الأداء تقليديا كان الأداء يستخدم لمراقبة الأداء المالي للمنظمة وفق مجموعة معينة من المعايير ال...
اما بالنسبة للترميم الكيميائي التي تحتاجها المخطوطات اذا كانت مصابة في نسيج الورق والتي يمكن ان تكون...
اما بالنسبة للترميم الكيميائي التي تحتاجها المخطوطات اذا كانت مصابة في نسيج الورق والتي يمكن ان تكون...