PhD. Transactions of Machine Elements Division. Lund 1973

The following papers are included in this dissertation:

• Stresses in External Involute Spur Gears. Me 53, Acta Polytechnica Scandinavica. Stockholm 1970.
• Tension of a Strip with Two Semi-circular Notches. Transactions of Machine Elements Division. Lund 1973.

Abstract:

The problem of uniaxial tension of a strip with two semi-circular notches is solved numerically. The results show good agreement with theoretical results by other authors except in the case of small notch depth compared to the width of the strip.

This work shows that stress concentration problem in the plane theory of elasticity can be solved with rather simple numerical methods by means of a modern digital computer even in symmetric problems, where the numerical method used is more slowly convergent than in antisymmetric problems.

In case with notches of complicated geometry where theoretical calculations will be very difficult to carry out the present numerical method of a similar one will be useful, I hope.

• On the Optimum Design of external Involute Gears. Transactions of Machine Elements Division. Lund 1973.

Abstract:

 Gear geometry based on the gear centre distance is studied. both standard and modified spur and helical gears are treated. This geometry is used to derive new non-dimensional gear contact pressure, based on equal centre distance, equal torque on the pinion and equal gear ratio.

The optimum analysis shows the advantage of using modified gear ratio.

Still better would be a choice of a pressure angle ≥ 25°.

Modern gear materials can after hardening stand much higher contact pressures. The risks of gear bending fatigue will then increase. This requires more calculations on accurate gear bending stresses, before greater pressure angles can be standardised.