ISO_TC_44___N_1757

8/13/2019 ISO_TC_44___N_1757

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Mechanical joining — Tensile shear testing of single joint specimens — Specimendimensions and test procedure

Assemblage mécanique — Essais quasi statiques de traction-cisaillement des échantillons à jonction unique —…

(de: Mechanisches Fügen — Scherzugprüfung von Einpunktproben — Probenmaße und Prüfung )

Parts of the draft shaded in ellow need further consideration.

Dokument-Typ: NormDokument-Untertyp:Dokumentstufe: EntwurfDokumentsprache: D

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Contents Page

Foreword

Foreword .........................................................................................................................................................3

1 Scope..................................................................................................................................................4

2 Normative references........................................................................................................................4

3 Terms and definitions .......................................................................................................................4

4 Test specimens and types of tests..................................................................................................6

5 Test equipment and test procedure ................................................................................................7

6 Failure mode ......................................................................................................................................9

7 Test report ..........................................................................................................................................9 A.1 General .............................................................................................................................................10 A.2 Typical failure modes of semi-tubular self piercing rivet joints under shear load...................10

A.3 Typical failure modes of solid self piercing rivet joints ..............................................................11

A.4 Typical failure modes of clinch joints ...........................................................................................12 A.5 Typical failure modes of screwed joints .......................................................................................13 A.6 Typical failure modes of joints made with self clinching or self piercing nuts ........................14 A.7 Typical failure modes of joints made with self clinching or self piercing bolts .......................15 A.8 Typical failure modes of blind rivet joints ....................................................................................16 A.9 Typical failure modes of lock bolt joints.......................................................................................17 A.10 Slippage in a mechanical joint .......................................................................................................18

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1 Scope

This standard specifies the geometry of the test specimens and the procedure for the tensile shear testing ofsingle mechanical joints on single and multi-layer specimens up to a single sheet thickness of 4,5 mm.

The term sheet, as used in this standard, includes extrusions and cast materials.

The purpose of the tensile shear test is to determine the mechanical characteristics and failure types of the joints made with the different methods.

2 Normative references

The following referenced documents are indispensable for the application of this document. For datedreferences, only the edition cited applies. For undated references, the latest edition of the referenceddocument (including any amendments) applies.

ISO 2768-1, General tolerances — Tolerances for linear and angular dimensions without individual tolerance

indications

ISO 7500-1 Metallic materials — Verification of static uniaxial testing machines — Part 1:Tension/compression testing machines — Verification and calibration of the force-measuring system

3 Terms and definitions

For the purpose of this document, the following terms and definitions apply.

3.1tensile shear load

F max.

maximum load, recorded in the test

Note If required, further characteristic data, e.g. F p0,2 (see 3.2), stiffness of the specimen c (see 3.6) or slope of the

force curve γ, energy dissipation W (see 3.7), can be determined according to the shear diagram given in Figure 4.

3.2elastic load limitF p0,2

maximum load before plastic or permanent deformation of 0,2 % occurs

3.3displacement

s

increase in the length of the specimen during the tensile shear test

3.4

displacement at the maximum load F max

sFmax

amount of displacement measured at maximum load F max

3.5displacement at 0,3F max

s0,3Fmax

amount of displacement measured at 0,3F max

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3.6stiffness in elastic range

c

ratio of increase of load to the increase of elongation in the elastic range (c = Δ F /Δ s)

3.7dissipated energy

W

work or area under the load curve

3.8dissipated energy up to F max W Fmax

area under the force curve up to the point of maximum tensile shear load F max

∫=

⋅=max

max

0

F

F

s

s

ds F W

3.9dissipated energy up to 0,3F max W 0,3Fmax area under the load curve up to the point where the tensile shear force drops to 30% of F max

∫=

⋅=

max3,0

max3,0

0

F

F

s

s

ds F W

3.10dissipated energy up to fracture

W fracture total area under the force curve

∫=

⋅= fracture s

s

fracture ds F W 0

3.11

displacement at maximum load F max sFmax

displacement at which the maximum load F max is recorded

3.12displacement at 0,3F max s0,3Fmax

displacement at which 0,3 F max is recorded

3.13form fit…(Dr. Singh)

3.14force fit…(Dr. Singh)

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4 Test specimens and types of tests

Tolerances according to ISO 2768-1 are applicable to the dimensions of the specimens given in Table 1.

((Missing reference to Figures 1 and 2))

Keya overlapb coupon widthl c length of clamped areal s total length of specimen

l g specimen length between clampsl t coupon lengtht 1 , t 2 sheet thickness

1 shim plates

Figure 1 —Single-lap tensile shear test specimens

((2nd

specimen with indication of visual and blind side and reverse))

Key

1 shim plates

Figure 2 — Examples of different sheet testing arrangements for tensile shear test specimens

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Stacking order of the sheets, the joining directions, the visible and blind side, etc. shall be agreed uponbetween the contracting parties.

Table 1 — Specimen dimensions

Thickness ofsheet

t 1; t 2

Overlap

a

Specimenwidth

b

Length ofclamped area

l c

Specimen lengthbetween clamps

l g

mm mm mm

≤ 4,5 5 × d 7 × d ≥ 45 95

NOTE Total specimen length: l s = l g + 2 l c, where the length of the clamped area is to be selected

in accordance with the testing machine being used.

d Shank diameter of blind rivets and self-locking collar bolts as well as nominal diameter of thread at

screws.

5 Test equipment and test procedure

The test specimen is clamped in a tensile testing machine according to ISO 7500-1, in such a manner, thatthe clamps are at the required distance from one another. For sheet thicknesses > 1 mm or where the ratio ofthe thicknesses is >1,4, shim plates shall be used for clamping the test specimen in the grips of the tensiletesting machine to ensure load concentricity (see Figure 3 b) and c)). Shim plates can be joined by suitable

joining method, e.g. resistance spot welding, adhesive bonding.

Testing shall be carried out at room temperature.

The speed of testing is 10 mm/min.

NOTE If tests at higher speeds show that the higher testing speed has no influence on the test results, then the higher

testing speed may be used for the tensile shear tests.

The elongation shall be measured as the displacement of the crosshead or by using extension callipergauges, laser measuring equipment or other suitable extension sensors with a defined length directly on thespecimen. Measurements made using signals from the crosshead should, if necessary, be corrected by takingthe stiffness of the machine into consideration. The sensing method used and the defined length of thespecimen measured shall be recorded in the test report.

Tests results are comparable only when the tests are carried out under identical boundary conditions.

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a) Test arrangementwithout shim plates

b) Test arrangementwith shim plates (two

layers)

c) Test arrangement with shimplates (three layers)

Key

1 shim plates

Figure 3 — Set-up for tensile shear test specimens

Figure 4 illustrates a load elongation diagram for specimens with form and force fit joints. Correspondingdiagrams for force fit joints can exhibit slippage before the yield point. In addition different diagrams can be theresult of different combinations of joining methods, sheet materials and thicknesses, as well as specimengeometries.

F max

s Fmax

0,3Fmax

s 0,3 Fmax s Fracture

γ

F

F p 0,2

W

s

Key

F loads elongation

Figure 4— Characteristic values of a load-elongation diagram for the tensile shear test

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6 Failure mode

The failure mode after tensile shear testing shall be classified according to Annex A.

7 Test report

The test report shall contain the following information:

a) name of the operator and/or the examining body;

b) designation of this standard (ISO 12996);

c) date and signature of the operator or the examining body;

d) joining technology;

e) joining parameters and joining equipment, fastener used;

f) specimen material and material condition;

g) specimen dimensions;

h) testing machine, test speed;

i) defined length on specimen and gauge type used for displacement measurements single values, meanvalues and standard deviation of the characteristic values;

j) individual test results, standard deviation, Coefficient of variation for the forces and the elongation

k) failure mode;

l) any additional remarks if required.

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Annex A(normative)

Types of joint failure

A.1 General

Depending on the joining technology, different types of failure can occur. Some of these are specific to the joining technology employed and should be recorded in the test report. Typical failure modes for clinch, selfpiercing rivet and screwed joints are shown, by way of example, in Figures A.1 to A.8.

Criteria for a failure of a mechanical joint are to be agreed between contracting parties. Following figures givetypical failure modes at the end of the test.

A.2 Typical failure modes of semi-tubular self piercing rivet joints under shear load

a) Rivet pull out from bottom sheet

b) Pull out of rivet head

c) Failure of the specimen material

d) Rivet failure

Figure A.1 — Typical failure modes of semi-tubular self piercing rivet joints under shear load

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A.3 Typical failure modes of solid self piercing rivet joints

a) Rivet pull out from bottom sheet

b) Pull out of rivet head

c) Failure of the specimen material

d) Rivet failure

Figure A.2 — Typical failure modes of solid self piercing rivet joints under shear load

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A.4 Typical failure modes of clinch joints

a) Pull out

b) Neck fracture

c) Neck fracture with plastic deformation (mixed mode failure)

d) Pull out with neck fracture (mixed failure)

Figure A.3 — Typical failure modes of clinch joints

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A.5 Typical failure modes of screwed joints

a) Thread in specimen stripped

b) Upper (head side) component fails

Figure A.4 — Typical failure modes of screwed joints (self drilling and thread forming screws)

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A.6 Typical failure modes of joints made with self clinching or self piercing nuts

a) Impermissible specimen deformation or pull out of the nut

b) Specimen tear-out

c) Bolt failure

Figure A.5— Typical failure modes of joints made with self clinching or self piercing nuts

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A.7 Typical failure modes of joints made with self clinching or self piercing bolts

a) Impermissible specimen deformation or pull out of the bolt

b) Specimen tear-out

c) Bolt failure

Figure A.6 — Typical failure modes of joints made with self clinching or self piercing bolts

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A.8 Typical failure modes of blind rivet joints

a) Impermissible specimen deformation or rivet pull

b) Specimen tear out

c) Blind rivet failure

Figure A.7 — Typical failure modes of blind rivet joints

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A.9 Typical failure modes of lock bolt joints

a) Impermissible specimen deformation or pull out of the bolt

b) Specimen tear out

c) Lock bolt failure

Figure A.8 — Typical failure modes of lock bolt joints

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A.10 Slippage in a mechanical joint

Figure A.9 — Typical failure mode of slippage in a mechanical joint

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ISO_TC_44___N_1757