Case study - Morphology of a Beetle

Although male Priacma Serrata are easily collected, available data on internal morphology and biology are restricted to very few representatives. The use of X-ray microtomography (XMT) presented itself as a valuable technique for the investigation of insect structures. An important advantage of XMT over other methods is the possibility of a non-destructive investigation of internal structures.

Characteristics:

Using micro CT to non-destructively investigate insect morphology
Create an accurate FE mesh to analyse why the mandible has evolved to that shape
Ability to scale up STL mesh for rapid prototyping

Thanks to

J. Bond, University of Exeter
T. Hörnschemeyer, University of Göttingen, Germany

I Image Acquisition

The specimens for the X-ray tomography were transferred to 100% ethanol and dried in a Balzer CPD 030 Critical Point Dryer. The dry specimens were mounted with soft wax to the sample stage of the X-ray machine. All measurements and reconstructions were made with a Skyscan 1072 high-resolution Micro-CT system.

II Mesh and Model Generation

Slices from the XMT data were imported into ScanIP and a simple FloodFill algorithm applied to segment the head structure. The segmented beetle head is about 5 mm long and the mandible measures 1.2 x 2.8 mm. The segmented structure was then meshed within +ScanFE and exported to Abaqus for further analysis. In addition, a scaled up surface mesh (.stl) was exported to produce an RP model of the head and mandible.

III Simulation

A mesh of the head and mandible consisting of 70,000 nodes and 250,000 elements (the mandible on its own has 30,000 nodes and 106,000 elements) was imported into Abaqus were material properties and loads were applied. The results show that the mandible is curved to distribute stress, and it acts as a scoop mechanism.

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