9 November 2012 Update

This week the HES met to:

  • review the results of the stress testing of oak and douglas fir wood samples,
  • evaluate the latest design of the release mechanism,
  • discuss fundraising priorities, and
  • determine the timing of ordering building materials.

Images from the stress testing of the wood samples:

Laser cutting wood samples

Wood sample ready for stress testing.

Wood sample under stress testing

The results of from our stress testing of actual wood samples are as follows:

Specimen and orientation AKI’s Researched Values Material Tests Done by Ben
Pine Parallel to grain in Tension 107.6 MPa(114.5,16.89 63.5 MPa(67.57,9.96)
Pine Parallel to grain in Shear Tension 7.8 MPa(43.8,1.22) 21.5 MPa(120.7,3.36)
Pine Perpendicular to grain Tension 1.92 MPa
Pine Parallel to grain compression 49.9 MPa (42.3,7.38) 41.25 MPa(34.9,6.1)
Pine Perpendicular to grain compression 7.29 MPa
Pine Parallel to grain shear compression 24.41MPa
Pine Perpendicular to grain shear compression 5.67 MPa
Oak Parallel Tension 77.9 MPa(82.8,12.23) 43.6 MPa(46.43,6.84)
Oak Perpendicular Tension 6.35 MPa
Oak Shear Parallel 12.5 MPa(70.2,1.96) 37.39 MPa(209.98,5.86)
Oak Parallel Compression 41.8 MPa(35.4,6.56) 55.03 MPa(46.6,8.63)
Oak Perpendicular Compression 16.22 MPa

Safety Factor ≈ (Static, Dynamic)