Dr. Max Langer

Dr. Max Langer

Research Area C

Plant Biomechanics Group Freiburg, Botanic Garden Freiburg


Transition zones between rod-shaped and planar plant structures

Project description
In this project, which is funded by the Ministry of Science, Research and the Arts Baden-Württemberg as a sub-project of BioElast, I focus on the transition zone between rod-shaped and planar structures. Various foliage leaves serve as biological role models, since they generally consist of a rod-shaped leaf stalk and a planar leaf blade, which are connected by a smooth transition zone. Within a biomimetic bottom-up approach, I first want to gain a better understanding of the morphology, anatomy and biomechanics of these stalk-blade transition zones. My project partners from various scientific disciplines will then transfer this knowledge into technical applications.

Project outcomes
The goal of my PhD thesis was to explore bio-inspired and biomimetic approaches to overcome technical challenges in the field of architecture. According to conventional construction methods, rod-shaped and planar components are often joined together using a wide variety of individual elements. Because of the high stresses and strains that occur between these elements the systems are more susceptible to failure and maintenance.
One aim of the project was therefore to develop bio-inspired systems which connect these very different structures via damage-resistant and resilient transition zones. Ideally, these systems are adaptive in terms of their large, planar structures and can also easily withstand dynamic loads such as wind. Foliage leaves meet these requirements, but the transition zone between the rod-shaped petiole and the planar leaf blade is barely studied.
My work demonstrated that different gradients represent a key functional principle of the examined petioles and transition zones. These gradients are overlapping over the course of the petiole and the transition zone and are partially integrated over different hierarchical levels. This involves gradients of size, shape and rigidity. The interaction of these different gradients reduces stress peaks resulting from mechanical loads in and between the individual leaf components. Another important factor was the fiber-matrix structure common to plant tissue and subsequent the arrangement of the tissues within the leaf components. Finally, I could show that there is a separation of mechanical functions between the petiole and the transition zone. The petiole compensates for bending loads, while the petiole and the transition zone share torsional loads. All these principles together lead to the resilient transition zones that we know from leaves rustling in the wind.
Transferring these functional principles to the field of construction could make a major contribution to more resilient and less damage-prone technical transitions between rod-shaped and planar structures.

Dr. Olga Speck

Max Langer completed his dissertation in March 2022.

Current position
Software developer at Testo bioAnalytics GmbH with the focus on image processing, computer vision and machine learning.

Publications in livMatS