Taylor, David
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Taylor, David
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Item-typ:Veröffentlichung, Damage, repair and regeneration in insect cuticle: The story so far, and possibilities for the futureThe exoskeleton of an insect can contain countless specializations across an individual, across developmental stages, and across the class Insecta. Hence, the exoskeleton's building material cuticle must perform a vast variety of functions. Cuticle displays a wide range of material properties which are determined by several known factors: the amount and orientation of the chitin fibres, the constituents and degree of cross-linking and hydration of the protein matrix, the relative amounts of exo- and endocuticle, and the shape of the structures themselves. In comparison to other natural materials such as wood and mammal bone, relatively few investigations into the mechanical properties of insect cuticle have been carried out. Of these, very few have focussed on the need for repair and its effectiveness at restoring mechanical stability to the cuticle. Insect body parts are often subject to prolonged repeated cyclic loads when running and flying, as well as more extreme "emergency" behaviours necessary for survival such as jumping, wedging (squeezing through small holes) and righting (when overturned). What effects have these actions on the cuticle itself? How close to the limits of failure does an insect push its body parts? Can an insect recover from minor or major damage to its exoskeleton "bones"? No current research has answered these questions conclusively.Wissenschaftlicher ArtikelBand:46Heft:1151 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, A systematic study of biological SE systems from complexity and design perspectivesPrevious research has presented the concept of self-engineering (SE) systems that aim to identify and preserve system functions autonomously. Examples of self-engineering responses include self-healing, self-repair, self-adapting and self-reconfiguration. Biology already utilises many of these responses to repair and survive, greater understanding of complexity in these biological systems could improve future bioinspired designs. This paper provides a novel systematic evaluation of the complexity of SE biological systems. Eight biological self-engineering systems identified are evaluated using Axiomatic design and complexity. The key functional requirements and design parameters for each biological system are identified. Design matrices were used to highlight different types of complexity. A further evaluation of eight SE biological systems is performed using the SE complexity theory; nine experts and 23 students used the complexity theory to complete a ranking exercise. The results of the ranking were analysed and compared, with a final normalised mean plotted for each factor and biological system. From the analysis of both studies, proposed design rules are presented to help designers handle complexity while creating new self-engineering systems inspired by biology.Wissenschaftlicher ArtikelBand:34Heft:1183 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, An investigation of crack propagation in an insect wing using the theory of critical distancesMaterials often have toughening mechanisms at different length scales. An interesting example is the insect wing, which consists of a membrane and veins. Previously we showed that cracks tend to arrest at the veins, which confer an increased toughness compared to that of the membrane. The Theory of Critical Distances (TCD) is an approach used to predict crack propagation based on the concept of a material-dependant length scale. In the present work, we monitored cracks propagating through wing samples and used finite element analysis (FEA) to model the interaction between cracks and veins. We found that the TCD could accurately predict the passage of a crack through a vein based on an estimate of the average stress over a material-dependant distance ahead of the crack tip. A picture emerges of the wing as a material with toughening mechanisms on two length scales: membrane level (critical distance 0.17 mm) and vein level (critical distance 0.58 mm). This work provides insights into how natural materials achieve enhanced toughness and could have applications as a concept in engineering design.Wissenschaftlicher ArtikelBand:232187 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Bridging the gap: wound healing in insects restores mechanical strength by targeted cuticle depositionIf an insect is injured, can it repair its skeleton in a manner which is mechanically strong and viable? Previous work has described the biological processes that occur during repair of insect cuticle, but until now, there has been no biomechanical assessment of the repaired area. We analysed the biomechanics of the injury repair process in the desert locust (Schistocerca gregaria). We show that after an incision, a healing process occurred which almost doubled the mechanical strength of locust tibial cuticle, restoring it to 66% of the original, intact strength. This repair process occurred by targeted cuticle deposition, stimulated by the presence of the injury. The cut surfaces remained unrepaired, but a patch of endocuticle was deposited, reinforcing the area and thus increasing the effective fracture toughness. The deposition rate of endocuticle inside the tibia increased fourfold compared with uninjured controls, but only on the dorsal side, where the incision was placed. The limb is highly loaded during jumping, so this partial restoration of strength will have a profound effect on the fitness of the insect. A finite-element model provided insights into the mechanics of the repair, predicting that the patch material reaches its ultimate strength before the fracture toughness of the existing cuticle is exceeded.Wissenschaftlicher ArtikelBand:13Heft:117136