Blood rheology in shear and uniaxial elongation

Kolbasov, Alexander; Comiskey, P. M.; Sahu, Rakesh P.; Sinha-Ray, Suman; Yarin, Alexander L.; Sikarwar, Basant Singh; Kim, Sun-Gu; Jubery, Talukder Z.; Attinger, Daniel

doi:10.1007/s00397-016-0964-1

Cited by 35 publications

(36 citation statements)

References 45 publications

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“…(note that the latter expressions involve two physical parameters of blood: its density ρ = 1.06 g/cm 3 , and its surface tension σ = 60.45 g/s 2 [36]). The subscript i in Eqs.…”

Section: Resultsmentioning

confidence: 99%

Hydrodynamics of back spatter by blunt bullet gunshot with a link to bloodstain pattern analysis

2017

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A theoretical model describing the blood spatter pattern resulting from a blunt bullet gunshot is proposed. The predictions are compared to experimental data acquired in the present work. This hydrodynamic problem belongs to the class of the impact hydrodynamics with the pressure impulse generating the blood flow. At the free surface, the latter is directed outwards and accelerated toward the surrounding air. As a result, the Rayleigh-Taylor instability of the flow of blood occurs, which is responsible for the formation of blood drops of different sizes and initial velocities. Thus, the initial diameter, velocity, and acceleration of the atomized blood drops can be determined. Then, the equations of motion are solved, describing drop trajectories in air accounting for gravity, and air drag. Also considered are the drop-drop interactions through air, which diminish air drag on the subsequent drops. Accordingly, deposition of two-phase (blood-drop and air) jets on a vertical cardstock sheet located between the shooter and the target (and perforated by the bullet) is predicted and compared with experimental data. The experimental data were acquired with a porous polyurethane foam sheet target impregnated with swine blood, and the blood drops were collected on a vertical cardstock sheet which was perforated by the blunt bullet. The highly porous target possesses a low hydraulic resistance and therefore resembles a pool of blood shot by a blunt bullet normally to its free surface. The back spatter pattern was predicted numerically and compared to the experimental data for the number of drops, their area, the total stain area, and the final impact angle as functions of radial location from the bullet hole in the cardstock sheet (the collection screen). Comparisons of the predicted results with the experimental data revealed satisfactory agreement. The predictions also allow one to find the impact Weber number on the collection screen, which is necessary to predict stain shapes and sizes. A theoretical model describing the blood spatter pattern resulting from a blunt bullet gunshot is proposed. The predictions are compared to experimental data acquired in the present work. This hydrodynamic problem belongs to the class of the impact hydrodynamics with the pressure impulse generating the blood flow. At the free surface, the latter is directed outwards and accelerated toward the surrounding air. As a result, the Rayleigh-Taylor instability of the flow of blood occurs, which is responsible for the formation of blood drops of different sizes and initial velocities. Thus, the initial diameter, velocity, and acceleration of the atomized blood drops can be determined. Then, the equations of motion are solved, describing drop trajectories in air accounting for gravity, and air drag. Also considered are the drop-drop interactions through air, which diminish air drag on the subsequent drops. Accordingly, deposition of two-phase (blood-drop and air) jets on a vertical cardstock sheet located between the shooter and the t...

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“…(note that the latter expressions involve two physical parameters of blood: its density ρ = 1.06 g/cm 3 , and its surface tension σ = 60.45 g/s 2 [36]). The subscript i in Eqs.…”

Section: Resultsmentioning

confidence: 99%

Hydrodynamics of back spatter by blunt bullet gunshot with a link to bloodstain pattern analysis

2017

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“…After atomization, the drops move through air and experience gravity and air drag forces, with the latter being diminished for the inner drops in the cloud due to collective effects associated with the aerodynamic drop-drop interaction [13][14][15]25,26]. At rates of strain as high as those characteristic of forward spatter, the viscoelasticity of blood [27] can significantly reduce drop ejection velocities, and thus should be accounted for.…”

Section: Theoreticalmentioning

confidence: 99%

“…where ρ is the density of the liquid target, 1060 kg/m 3 , γ is the surface tension of blood, 60.45 mN/m [27], andε is the local rate of strain. The rate of strain in the target is of the order oḟ…”

Section: A Chaotic Disintegration Of a Liquidmentioning

confidence: 99%

Theoretical and experimental investigation of forward spatter of blood from a gunshot

2018

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A theoretical model predicting forward blood spatter patterns resulting from a round nose bullet gunshot wound is proposed. The chaotic disintegration of a blood layer located ahead and aside of the bullet is considered in the framework of percolation theory. The size distribution of blood drops is determined, which allows for the prediction of a blood spatter cloud being ejected from the rear side of the target where the bullet exits. Then, droplet trajectories are numerically predicted accounting for gravity and air drag, which is affected by the collective aerodynamic interaction of drops through air. The model predicts the number and area of individual stains, as well as the stain distribution as a function of distance from the region of origin. The theoretical predictions are compared with experimental data acquired in this work from 9 mm Luger copper full metal jacket bullets fired from a handgun. The agreement between the predicted and experimentally measured parameters is found to be good. Disciplines

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“…There is also difficulty in converting from frequency to a nominal strain rate and assuming the storage modulus at that frequency to be equivalent to the Young's modulus at that strain rate [16]. This can be interpreted as attempting to find an analogy to the empirical Cox-Merz rule from rheology, which works well for complex fluids including blood [4,17]. However, the relaxation process in fluid flow is not the same as in deformation of a solid; therefore, a different approach is used in the present work.…”

Section: Introductionmentioning

confidence: 99%

Strain rate sensitivity of polycarbonate and vinyl ester from dynamic mechanical analysis experiments

Koomson

Zeltmann

Gupta

2018

Adv Compos Hybrid Mater

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Measuring the strain rate sensitivity of materials is desired to improve the design of polymeric parts in automotive and aerospace structures. In this work, we present a technique for determining the mechanical response of polymers at different temperatures and strain rates by converting frequency-domain dynamic mechanical analysis (DMA) data to the time domain. Two polymers of practical interest, vinyl ester and polycarbonate, are examined. The modulus of elasticity in the linear region is measured as a function of the applied strain rate and compared to predictions from the DMA transformation technique. Close agreement between the results obtained from the two techniques is observed over the studied range of strain rates. The transformation technique only relies on the assumptions of the linear theory of viscoelasticity and is expected to be applicable to a wide range of polymers and can also be extended to polymer-matrix composites.

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Blood rheology in shear and uniaxial elongation

Cited by 35 publications

References 45 publications

Hydrodynamics of back spatter by blunt bullet gunshot with a link to bloodstain pattern analysis

Hydrodynamics of back spatter by blunt bullet gunshot with a link to bloodstain pattern analysis

Theoretical and experimental investigation of forward spatter of blood from a gunshot

Strain rate sensitivity of polycarbonate and vinyl ester from dynamic mechanical analysis experiments

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