Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
  • G01N3/02—Details
  • G01N3/04—Chucks
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
  • G01N2203/02—Details not specific for a particular testing method
  • G01N2203/025—Geometry of the test
  • G01N2203/0254—Biaxial, the forces being applied along two normal axes of the specimen
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
  • G01N2203/02—Details not specific for a particular testing method
  • G01N2203/026—Specifications of the specimen
  • G01N2203/0262—Shape of the specimen
  • G01N2203/0272—Cruciform specimens

Definitions

• Cross-shaped, flat sample especially made of sheet metal for a
• the invention relates to a cross-shaped, planar sample, in particular made of sheet metal, for a two-axis material test in the area of high elongation according to the preamble of patent claim 1 .
• FIG. 1 of the drawing A flat cross sample according to Shiratori / Ikegami (J. Meck. Phys. Solids, 1968, vol. 16 pp 373 to 394, Pergamon Press, Great Britain) and Kreissig (dissertation 2.7.1982) according to FIG. 1 of the drawing, which is used for Purpose of testing materials under two-axis stress in a known Kreissig test facility. Because of the static indeterminacy of this known cross sample 1 (continuum problem), the stresses cannot be determined from the forces introduced into the cross sample 1 via tension members 2. In the intended measurement area 3, the center of this cross-test, no homogeneous voltage and distortion states can be achieved.
• the invention is based on the object of designing a cruciform, flat sample, in particular of sheet metal, in accordance with the type mentioned at the beginning in such a way that homogeneous stress and distortion states are achieved in the measuring range when the sample is subjected to two axes, in order to obtain S-fcoff equations classifying the so-called simple substances.
• the formation of slots according to the invention in the sample arms forming the La introduction elements makes it possible to achieve a homogeneous stress state in the measurement area, since the arrangement of the slots in the load introduction elements prevents the tension trajectories in the central region of the sample from evading.
• the reinforcement of the sample arms according to the invention also makes it possible that large plastic deformations in the measuring range can be achieved even with cross-samples made from deep-drawing steels. Without additional measures to reinforce the sample arms, the sample arms would suffer large plastic strains in deep-drawing rooms with approximately the same tensile forces in both directions before the measuring area would plasticize.
• arms made of high-strength material can preferably be welded on to reinforce the sample arms, additional materials for geometrically reinforcing the sample arms can be applied to them, or the sample arms can be work-hardened by rolling to raise the yield point.
• FIG. 4 is a plan view of a slotted cross sample
• FIG. 5 shows a top view of the cross test according to FIG. 4, the course of the tension trajectories with uniaxial tensile load being shown parallel to the X-coordinate
• FIG. 5 shows a plan view of the slotted cross sample
• FIG. 6 is a plan view of a slotted cross sample with welded arms made of a higher strength material
• FIG. 7 is a plan view of a slotted cross sample with geometric reinforcement of the sample arms
• Fig. 8 is an end view of the embodiment of the cross test
• Fig. 9 is an end view of a cross sample with rolled sample arms.
• FIG. 4 shows the top view of the cross sample 1, the sample arms 5 of which form load-sharing elements with the length 1 and the width a.
• the load division elements 5 have slots 6 which extend to the measuring area 3 of the cross sample 1.
• the tension trajectories 4 in the slotted cross test 1 under uniaxial tensile force F run parallel to the X coordinate in the measuring range 3 of the cross test 1.
• FIG. 6 shows the top view of an embodiment of the cross sample 1, the sample arms 5 forming the load introduction elements, which are welded to the measuring area 3 of the cross sample 1, are made of a higher-strength material than the central region 3 of the cross sample 1, thereby stiffening the Sample arms 5 is given, and each have slots 6 running parallel to their longitudinal direction.
• the slots 6 extend from a part 7, which in the clamping jaw of a test direction can be clamped up to the measuring area 3 of the cross sample 1 and are thus shorter than the length of the sample arm 5.
• the slots 6 are arranged at the same distance from one another over the width (a) of each sample arm 5, with the to the longitudinal edges 8 slots 6 adjacent to the sample arm also have the distance c from the longitudinal edges 8.
• FIG. 7 and 8 show another embodiment of the cross sample 1, in which the sample arms 5 are reinforced by applied additional material.
• the additional material is applied in the form of webs 9 on both sides of the sample arms 5, the webs 9 running parallel to the slots 6 between them and between the longitudinal edges 8 of the sample arms -5 and the adjacent slots 7.
• the width of the webs 9 made of additional material is less than the distance c between the slots 7.
• homogeneous stress and strain states are also given in a biaxial material test.
• the sample arms 5 have been rolled to increase the yield point from the thickness d of the central region 3 of the cross sample 1 to the thickness d (d ⁇ Td) and have thus been strain-hardened for reinforcement.
• d ⁇ Td thickness of the cross sample 1
• homogeneous stress and distortion states can be achieved in the measurement area 3 under two-axis stress.

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• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
• Force Measurement Appropriate To Specific Purposes (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6380231

Family Applications (1)

Country Status (5)

Families Citing this family (25)

Family Cites Families (4)

• 1989
  • 1989-05-03 DE DE3914966A patent/DE3914966C2/de not_active Expired - Lifetime
• 1990
  • 1990-04-21 JP JP2505937A patent/JPH071213B2/ja not_active Expired - Lifetime
  • 1990-04-21 US US07/635,627 patent/US5144844A/en not_active Expired - Fee Related
  • 1990-04-21 EP EP90906121A patent/EP0423279A1/de not_active Withdrawn
  • 1990-04-21 WO PCT/DE1990/000298 patent/WO1990013804A1/de not_active Application Discontinuation

Non-Patent Citations (1)

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