Bending Test

 

Bending properties of composite materials are commonly tested according to DIN EN ISO 14125, DIN EN ISO 178 and DIN 53293, using a three point or four point flexural bending test device. The flexural tests provide values for the modulus of elasticity in bending, flexural stress, flexural strain  and the flexural stress-strain response of the material.

The test method involves a specified test fixture on a universal testing machine. The sample is placed on two supporting pins a set distance apart and a third (three point) or fourth (four point) loading pin is lowered from above at a constant rate until a given deformation or until sample failure.

The major difference between the two methods being that the addition of a 4th bearing brings a much larger portion of the beam to the maximum stress, providing a constant distribution of strain and deformation, as opposed to only the material right under the central bearing. Between the test fictures and the loading pins a shear stress is applied. It is mandatory to keep the shear stress lower than the tested material’s shear strength. Within the test area there is no shear stress at all.

Besides the static flexural test we also offer dynamic flexural testing, using our innovative dynamic flexural testing device. We are happy to give advice on characteristics of flexural testings.

Bending Test of flat specimen using DIN EN ISO 14125:1998-06, ASTM D 790-10

  • Standard test method for determination of bending properties of fiber reinforced composite materials
  • Laminates made of a thermosetting or thermoplastic matrix with unidirecional fibers
  • Fiber orientation: 0°, 90°, 0°/90°
  • Geometrie of specimen: 80…100mm x 10…15mm x 2…4mm
  • Doublers: not necessary
  • Strain gauges: 1 (for 3-Point) or 2 (for 4-Point) pc per specimen in longitudinal direction

3-Point Bending Test of flat specimen using DIN EN ISO 178:2003-06

  • Standard test method for determination of bending properties of fiber reinforced composite materials
  • Laminates made of short fiber reinforced thermosetting or thermoplastic
  • Fiber orientation: 0°, 90°, 0°/90°
  • Geometrie of specimen: 80mm x 10mm x 4mm
  • Doublers: not necessary
  • Strain gauges: 1 pc per specimen in longitudinal direction

3-Point Bending Test of flat specimen using DIN EN 2562:1997-05

  • Standard test method for determination of bending properties of fiber reinforced carbon materials for aerospace
  • Laminates made of a thermosetting or thermoplastic with unidirectional fibers
  • Fiber orientation: 0°
  • Geometrie of specimen: 100mm x 10mm x 2mm
  • Doublers: not necessary
  • Strain gauges: not necessary, device for monitoring the deflection available

3-Point Bending Test of flat specimen using DIN EN 2746:1998-10

  • Standard test method for determination of bending properties of fiber reinforced glass materials for aerospace
  • Laminates made of a thermosetting or thermoplastic with unidirectional fibers
  • Fiber orientation: 0°, 0°/90°
  • Geometrie of specimen: 60mm x 15mm x 3mm
  • Doublers: not necessary
  • Strain gauges: not necessary, device for monitoring the deflection available

Bending Test of flat specimen using ASTM D 7264-07

  • Standard test method for determination of bending properties of fiber reinforced composite materials
  • Laminates made of a thermosetting or thermoplastic matrix with unidirecional fibers
  • Routine for 3-Point or 4-Point Bending Test
  • Fiber orientation: 0°, 90°, 0°/90°
  • Geometrie of specimen: 160mm x 13mm x 4mm
  • Doublers: not necessary
  • Strain gauges: 1 pc per specimen in longitudinal direction