温度による木材強さの變化に就て  [in Japanese] The Effect of Temperature on the Strength of Wood  [in Japanese]

Impact bending tests were carried out on specimens of Spruce and Plywood between the range of temperatures from +60℃ to -60℃. The testing machine used was an Amsler's 4 ton universal machine for testing wood. When this machine is used for impact bending, it is possible to measure the maximum pressure on the supports besides the energy required to break the test pieces, so that the equivalent modulus of rupture can also be computed. Results show that both Spruce and Plywood change in their mechanical properties with variation of temperatures. Thus the absorbed energy shows a minimum between 0℃ and -10℃, and the equivalent modulus of rupture increases almost linearly with decrease in temperature. Moveover prolonged cooling produced no difference in the results as compared with those cooled for a short time. And it was observed that test pieces which were first cooled and then brought back to the normal temperature regained their initial properties.