Teacher tree: The evolution of notch shape optimization from complex to simple

Shape optimization of engineering components following the design rules of nature was started in the late eighties in the Karlsruhe Research Centre. The key idea was the natural observation that trees care by load-adaptive growth to maintain a uniform stress distribution at their surface. This means also that high stress peaks (notch stresses) are avoided as potential failure points. The computer simulation of this adaptive growth has been called Computer Aided Optimization (CAO). CAO is based on the use of the Finite-Element-Method (FEM).The present paper shows how 15 years after the CAO-method drastic simplifications are available. So notch shape optimization in many cases can be done without the FEM-codes, with a pocket calculator or even simpler with a graphic method.