Burrow extension by crack propagation

Dorgan, Kelly M.; Jumars, Peter A.; Johnson, Bruce D.; Boudreau, Bernard P.; Landis, Eric N.

doi:10.1038/433475a

Cited by 153 publications

(131 citation statements)

References 7 publications

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“…Muddy marine sediments are elastic solids in which bubbles grow [3] and worms extend burrows by fracture [5]. The burrow around the polychaete, Nereis virens, is a tongue-depressor-shaped crack that extends laterally away from the worm and compresses the worm dorsoventrally (Fig.…”

Section: Burrowing In Mudmentioning

confidence: 99%

“…Perhaps more importantly, the mechanical responses of muds and sands to forces are less well understood than those of fluids, which are governed by the Navier-Stokes equations [2]. Recent advances in understanding of the mechanics of muds [3] and sands [4] and their application to burrowing [5,6] suggest that not only are the mechanics of crawling and burrowing very different, but mechanisms of burrowing in sands and muds reflect the differences in mechanical properties of the two media [7].…”

Section: Introductionmentioning

confidence: 99%

“…The high cost of gastropod locomotion largely results from the cost of mucus production, although inefficiencies in crawling with a hydrostatic skeleton are also a factor [13]. The cost of transport for abalone crawling underwater, however, is much lower than that of slugs [17], and studies of burrowing in marine muds [18,19] likely overestimated the cost of transport because the mechanics of burrowing were not understood [5,7]. The cost of maintaining body posture against gravitational forces in air may be an important factor distinguishing terrestrial from aquatic hydrostatic locomotion, although direct comparisons are lacking.…”

Section: Introductionmentioning

confidence: 99%

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Environmental Constraints on the Mechanics of Crawling and Burrowing Using Hydrostatic Skeletons

Dorgan

2010

Exp Mech

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Mechanics, kinematics, and energetics of crawling and burrowing by limbless organisms using hydrostatic skeletons depend on the medium and mode in which the organism is moving. Whether the animal is moving over or through a solid has long been considered important enough to distinguish crawling and burrowing as different terms, and in fact the mechanics are very different. Crawlers use mechanisms to increase friction to generate thrust while reducing resistive friction. Burrowers in elastic muds extend their burrows by fracture, whereas sands are fluidized by burrowers much larger than grain sizes and smaller burrowers displace individual grains. Gravitational forces depend on how closely the density of the organism matches that of its fluid surroundings, therefore frictional forces depend on whether the organism is moving through air or water and fluidization on whether sands are saturated or unsaturated.

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Section: Burrowing In Mudmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Environmental Constraints on the Mechanics of Crawling and Burrowing Using Hydrostatic Skeletons

Dorgan

2010

Exp Mech

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“…The study of climbing has led to undiscovered templates (11) that define physical interactions through frictional van der Waals adhesion (12,13) and interlocking with claws (14) and spines (5). Burrowing (15,16), sand swimming (17), and locomotion in tunnels (18) have yielded new findings determining the interaction of bodies, appendages, and substrata.…”

mentioning

confidence: 99%

Cockroaches traverse crevices, crawl rapidly in confined spaces, and inspire a soft, legged robot

Jayaram

Full

2016

Proc. Natl. Acad. Sci. U.S.A.

145

112

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Jointed exoskeletons permit rapid appendage-driven locomotion but retain the soft-bodied, shape-changing ability to explore confined environments. We challenged cockroaches with horizontal crevices smaller than a quarter of their standing body height. Cockroaches rapidly traversed crevices in 300-800 ms by compressing their body 40-60%. High-speed videography revealed crevice negotiation to be a complex, discontinuous maneuver. After traversing horizontal crevices to enter a vertically confined space, cockroaches crawled at velocities approaching 60 cm·s −1 , despite body compression and postural changes. Running velocity, stride length, and stride period only decreased at the smallest crevice height (4 mm), whereas slipping and the probability of zigzag paths increased. To explain confined-space running performance limits, we altered ceiling and ground friction. Increased ceiling friction decreased velocity by decreasing stride length and increasing slipping. Increased ground friction resulted in velocity and stride length attaining a maximum at intermediate friction levels. These data support a model of an unexplored mode of locomotion-"body-friction legged crawling" with body drag, friction-dominated leg thrust, but no media flow as in air, water, or sand. To define the limits of body compression in confined spaces, we conducted dynamic compressive cycle tests on living animals. Exoskeletal strength allowed cockroaches to withstand forces 300 times body weight when traversing the smallest crevices and up to nearly 900 times body weight without injury. Cockroach exoskeletons provided biological inspiration for the manufacture of an origami-style, soft, legged robot that can locomote rapidly in both open and confined spaces.T he emergence of terradynamics (1) has advanced the study of terrestrial locomotion by further focusing attention on the quantification of complex and diverse animal-environment interactions (2). Studies of locomotion over rough terrain (3), compliant surfaces (4), mesh-like networks (5), and sand (6-8), and through cluttered, 3D terrain (9) have resulted in the discovery of new behaviors and novel theory characterizing environments (10). The study of climbing has led to undiscovered templates (11) that define physical interactions through frictional van der Waals adhesion (12, 13) and interlocking with claws (14) and spines (5). Burrowing (15, 16), sand swimming (17), and locomotion in tunnels (18) have yielded new findings determining the interaction of bodies, appendages, and substrata.Locomotion in confined environments offers several challenges for animals (18) that include limitations due to body shape changes (19,20), restricted limb mobility (21), increased body drag, and reduced thrust development (22). Examining the motion repertoire of soft-bodied animals (23), such as annelids (19), insect larvae (24), and molluscs (25), has offered insight into a range of strategies used to move in confined spaces. Inspiration from softbodied animals has fueled the explosive growth in soft robo...

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“…A photoelastic resin is a birefringent material designed to interact with polarized light (where all waves are oriented in the same plane) to illuminate strain patterns within the resin as a series of interference colours. Photoelastic materials have been used in biological studies to measure forces produced by insect walking [38,39], strains in the substrate during earthworm burrowing [40] and internal strains of materials during cutting experiments [14]. The interference colours in a photoelastic material are a function of both the magnitude of the strain present in the material as well as the thickness of the piece of material.…”

Section: Photoelastic Testsmentioning

confidence: 99%

Virtual experiments, physical validation: dental morphology at the intersection of experiment and theory

Anderson

Rayfield

2012

J. R. Soc. Interface.

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Computational models such as finite-element analysis offer biologists a means of exploring the structural mechanics of biological systems that cannot be directly observed. Validated against experimental data, a model can be manipulated to perform virtual experiments, testing variables that are hard to control in physical experiments. The relationship between tooth form and the ability to break down prey is key to understanding the evolution of dentition. Recent experimental work has quantified how tooth shape promotes fracture in biological materials. We present a validated finite-element model derived from physical compression experiments. The model shows close agreement with strain patterns observed in photoelastic test materials and reaction forces measured during these experiments. We use the model to measure strain energy within the test material when different tooth shapes are used. Results show that notched blades deform materials for less strain energy cost than straight blades, giving insights into the energetic relationship between tooth form and prey materials. We identify a hypothetical 'optimal' blade angle that minimizes strain energy costs and test alternative prey materials via virtual experiments. Using experimental data and computational models offers an integrative approach to understand the mechanics of tooth morphology.

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Burrow extension by crack propagation

Cited by 153 publications

References 7 publications

Environmental Constraints on the Mechanics of Crawling and Burrowing Using Hydrostatic Skeletons

Environmental Constraints on the Mechanics of Crawling and Burrowing Using Hydrostatic Skeletons

Cockroaches traverse crevices, crawl rapidly in confined spaces, and inspire a soft, legged robot

Virtual experiments, physical validation: dental morphology at the intersection of experiment and theory

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