scholarly journals Ballistic impact of single particles into gelatin : experiments and modeling with application to transdermal pharmaceutical delivery

2021 ◽  
Author(s):  
Rachel Ann Guha
Keyword(s):  
Material Properties ◽  
High Speed ◽  
Scaling Laws ◽  
Impact Behavior ◽  
Powder Injection ◽  
Fe Model ◽  
Calibration System ◽  
Human Dermis ◽  
Steel Balls ◽  
Impact Experiments

The high speed penetration of particles into the human dermis is of interest for targeted drug delivery by transdermal powder injection. However, performing well-controlled single impact experiments with micron scale particles on dermal tissues is difficult. Therefore, the suitability of the use of a dimensionally scaled up 'model' system utilizing steel balls impacting a gelatin to simulate the perforation of micron sized gold particles into human skin was investigated. A finite element (FE) model of a 'calibration' system consisting of a 2 μm gold sphere impacting the human dermis at 651 m/s was used to extract the combinations of possible epidermal material properties which allowed an FE predicted penetration able to match measured data from an existing study in the literature. Novel scaling laws were developed to link the 'model' and 'calibration' systems, and impact experiments were performed on gelatins of various formulations to determine the formulation that produced a penetration which, when scaled, matched that of the calibration system. The resulting material properties of the gelatin were appropriately scaled and used to choose the best combination of skin material properties. In this manner, a quasi static elastic modulus of 2.25 MPa was found for skin, in good agreement with reported values from the literature. Further experiments were performed with steel, polymethyl-methacrylate, titanium, and tungsten carbide balls impacting the gelatin, in order to determine the effects of particle size and density on penetration depth. FE simulations of both the model and calibration systems confirmed the scaling relationships and impact behavior found in these experiments. Both the FE model and the steel-gelatin experiments were able to predict the penetration trends found by other investigators in the examination of typical particles used for vaccine delivery. It can therefore be concluded that scaled up systems utilizing ballistic gelatins can be used to investigate the performance of transdermal powder injection technology.

scholarly journals Ballistic Impact of Single Particles into Gelatin : Experiments and Modeling with Application to Transdermal Pharmaceutical Delivery

2021 ◽  
Author(s):  
Rachel Ann Guha
Keyword(s):  
Material Properties ◽  
High Speed ◽  
Scaling Laws ◽  
Impact Behavior ◽  
Powder Injection ◽  
Fe Model ◽  
Calibration System ◽  
Human Dermis ◽  
Steel Balls ◽  
Impact Experiments

The high speed penetration of particles into the human dermis is of interest for targeted drug delivery by transdermal powder injection. However, performing well-controlled single impact experiments with micron scale particles on dermal tissues is difficult. Therefore, the suitability of the use of a dimensionally scaled up 'model' system utilizing steel balls impacting a gelatin to simulate the perforation of micron sized gold particles into human skin was investigated. A finite element (FE) model of a 'calibration' system consisting of a 2 μm gold sphere impacting the human dermis at 651 m/s was used to extract the combinations of possible epidermal material properties which allowed an FE predicted penetration able to match measured data from an existing study in the literature. Novel scaling laws were developed to link the 'model' and 'calibration' systems, and impact experiments were performed on gelatins of various formulations to determine the formulation that produced a penetration which, when scaled, matched that of the calibration system. The resulting material properties of the gelatin were appropriately scaled and used to choose the best combination of skin material properties. In this manner, a quasi static elastic modulus of 2.25 MPa was found for skin, in good agreement with reported values from the literature. Further experiments were performed with steel, polymethyl-methacrylate, titanium, and tungsten carbide balls impacting the gelatin, in order to determine the effects of particle size and density on penetration depth. FE simulations of both the model and calibration systems confirmed the scaling relationships and impact behavior found in these experiments. Both the FE model and the steel-gelatin experiments were able to predict the penetration trends found by other investigators in the examination of typical particles used for vaccine delivery. It can therefore be concluded that scaled up systems utilizing ballistic gelatins can be used to investigate the performance of transdermal powder injection technology.

scholarly journals Ballistic impact of single particles into gelatin : experiments and modeling with application to transdermal pharmaceutical delivery

2021 ◽  
Author(s):  
Rachel Ann Guha
Keyword(s):  
Material Properties ◽  
High Speed ◽  
Scaling Laws ◽  
Impact Behavior ◽  
Powder Injection ◽  
Fe Model ◽  
Calibration System ◽  
Human Dermis ◽  
Steel Balls ◽  
Impact Experiments

The high speed penetration of particles into the human dermis is of interest for targeted drug delivery by transdermal powder injection. However, performing well-controlled single impact experiments with micron scale particles on dermal tissues is difficult. Therefore, the suitability of the use of a dimensionally scaled up 'model' system utilizing steel balls impacting a gelatin to simulate the perforation of micron sized gold particles into human skin was investigated. A finite element (FE) model of a 'calibration' system consisting of a 2 μm gold sphere impacting the human dermis at 651 m/s was used to extract the combinations of possible epidermal material properties which allowed an FE predicted penetration able to match measured data from an existing study in the literature. Novel scaling laws were developed to link the 'model' and 'calibration' systems, and impact experiments were performed on gelatins of various formulations to determine the formulation that produced a penetration which, when scaled, matched that of the calibration system. The resulting material properties of the gelatin were appropriately scaled and used to choose the best combination of skin material properties. In this manner, a quasi static elastic modulus of 2.25 MPa was found for skin, in good agreement with reported values from the literature. Further experiments were performed with steel, polymethyl-methacrylate, titanium, and tungsten carbide balls impacting the gelatin, in order to determine the effects of particle size and density on penetration depth. FE simulations of both the model and calibration systems confirmed the scaling relationships and impact behavior found in these experiments. Both the FE model and the steel-gelatin experiments were able to predict the penetration trends found by other investigators in the examination of typical particles used for vaccine delivery. It can therefore be concluded that scaled up systems utilizing ballistic gelatins can be used to investigate the performance of transdermal powder injection technology.

scholarly journals Ballistic Impact of Single Particles into Gelatin : Experiments and Modeling with Application to Transdermal Pharmaceutical Delivery

2021 ◽  
Author(s):  
Rachel Ann Guha
Keyword(s):  
Material Properties ◽  
High Speed ◽  
Scaling Laws ◽  
Impact Behavior ◽  
Powder Injection ◽  
Fe Model ◽  
Calibration System ◽  
Human Dermis ◽  
Steel Balls ◽  
Impact Experiments

The high speed penetration of particles into the human dermis is of interest for targeted drug delivery by transdermal powder injection. However, performing well-controlled single impact experiments with micron scale particles on dermal tissues is difficult. Therefore, the suitability of the use of a dimensionally scaled up 'model' system utilizing steel balls impacting a gelatin to simulate the perforation of micron sized gold particles into human skin was investigated. A finite element (FE) model of a 'calibration' system consisting of a 2 μm gold sphere impacting the human dermis at 651 m/s was used to extract the combinations of possible epidermal material properties which allowed an FE predicted penetration able to match measured data from an existing study in the literature. Novel scaling laws were developed to link the 'model' and 'calibration' systems, and impact experiments were performed on gelatins of various formulations to determine the formulation that produced a penetration which, when scaled, matched that of the calibration system. The resulting material properties of the gelatin were appropriately scaled and used to choose the best combination of skin material properties. In this manner, a quasi static elastic modulus of 2.25 MPa was found for skin, in good agreement with reported values from the literature. Further experiments were performed with steel, polymethyl-methacrylate, titanium, and tungsten carbide balls impacting the gelatin, in order to determine the effects of particle size and density on penetration depth. FE simulations of both the model and calibration systems confirmed the scaling relationships and impact behavior found in these experiments. Both the FE model and the steel-gelatin experiments were able to predict the penetration trends found by other investigators in the examination of typical particles used for vaccine delivery. It can therefore be concluded that scaled up systems utilizing ballistic gelatins can be used to investigate the performance of transdermal powder injection technology.

Rate Dependent Material Model for Helmet Pads

2020 ◽  
Author(s):  
Timothy G. Zhang ◽  
A. H. Fulton ◽  
K. Ravi-Chandar ◽  
Sikhanda S. Satapathy
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
High Speed ◽  
Material Model ◽  
High Speed Camera ◽  
Low Velocity ◽  
Rate Dependent ◽  
Military Helmet ◽  
The Impact ◽  
Impact Experiments

Abstract Foam pads are commonly used in sports and military helmet for energy absorption, form-fitting and comfort. Both for low velocity and high velocity applications, their rate-dependent mechanical properties need to be characterized to understand their ability to effectively modulate the transmitted stress pulse. Impact experiments were conducted on bilayer helmet pads at a range of velocities covering low to medium rates up to ∼7000/s. Images from high-speed camera were used to construct x-T diagrams to measure the shock speeds from the impact experiments. Numerical simulations were carried out to validate a foam pad model and to understand experimental uncertainties. The scatter in the measured shock speeds was found to be related to the scatter in the material properties.

Experimental and Modeling Studies of Looping Process for Wire Bonding

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Fuliang Wang ◽  
Yun Chen
Keyword(s):  
Finite Element ◽  
Friction Force ◽  
Material Properties ◽  
High Speed ◽  
Gold Wire ◽  
Tension Force ◽  
Fe Model ◽  
High Speed Camera ◽  
Dynamic Finite Element ◽  
Key Technologies

Looping is one of the key technologies for modern thermosonic wire bonders, and it has been affected by many interacting factors. In this study, the wire looping process was observed with a high-speed camera, and the evolution of wire profiles during looping and the capillary trace were obtained through experiments. A dynamic finite element (FE) model was developed to learn the details of the looping process, where real capillary geometry dimensions, capillary trace, diameter of bonded ball and the gold wire material were used, and the friction force and air tension force were considered. The simulated profiles were compared with those of the experiment. Using the verified FE model, the effects of material properties, capillary parameters, and capillary traces on the looping process were studied, and the relationships between the final profiles and parameters were discussed.

High Speed Fracture Phenomena in Dyneema Composite

2007 ◽  
Vol 353-358 ◽  
pp. 120-125 ◽  
Author(s):  
Beate D. Heru Utomo ◽  
B.J. van der Meer ◽  
L.J. Ernst ◽  
D.J. Rixen
Keyword(s):  
Material Properties ◽  
Cohesive Zone ◽  
High Speed ◽  
Material Model ◽  
Protection Level ◽  
Projectile Impact ◽  
New Material ◽  
Specific Material ◽  
Strength And Stiffness ◽  
Impact Experiments

Dyneema composite is used in lightweight armour applications, because of its high specific material properties such as strength and stiffness. In armour applications, Dyneema composite is used to protect people or vehicles from projectile impact. In order to be able to guarantee a certain protection level, an accurate prediction of fracture phenomena that are caused by projectile impact is required. Currently, fracture phenomena such as delamination and fibre fracture are not accurately described. This is because a good understanding of fracture phenomena in Dyneema composite lacks. Therefore, both Dyneema fibre and Dyneema composite are analysed by different (impact) experiments to gain more insight in both the fracture phenomena as well as in the material properties. Parallel to these experiments, a start is made with the development of a new material model in ABAQUS\Explicit using cohesive zone techniques that is able to predict the fracture phenomena due to projectile impact.

Ballistic Impact of Single Particles Into Gelatin: Experiments and Modeling With Application to Transdermal Pharmaceutical Delivery

2010 ◽  
Vol 132 (10) ◽  
Author(s):  
R. A. Guha ◽  
N. H. Shear ◽  
M. Papini
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
High Speed ◽  
Element Model ◽  
Powder Injection ◽  
Single Particles ◽  
Human Dermis ◽  
Injection Technology ◽  
Penetration Behavior ◽  
The Impact

The impact and penetration of high speed particles with the human skin is of interest for targeted drug delivery by transdermal powder injection. However, it is often difficult to perform penetration experiments on dermal tissue using micron scale particles. To address this, a finite element model of the impact and penetration of a 2 μm gold particle into the human dermis was developed and calibrated using experiments found in the literature. Using dimensional analysis, the model was linked to a larger scale steel ball-gelatin system in order to extract key material parameters for both systems and perform impact studies. In this manner, an elastic modulus of 2.25 MPa was found for skin, in good agreement with reported values from the literature. Further gelatin experiments were performed with steel, polymethyl methacrylate, titanium, and tungsten carbide balls in order to determine the effects of particle size and density on penetration depth. Both the finite element model and the steel-gelatin experiments were able to predict the penetration behavior that was found by other investigators in the study of the impact of typical particles used for vaccine delivery into the human dermis. It can therefore be concluded that scaled up systems utilizing ballistic gelatins can be used to investigate the performance of transdermal powder injection technology.

scholarly journals A 3-D Finite-Element Minipig Model to Assess Brain Biomechanical Responses to Blast Exposure

2021 ◽  
Vol 9 ◽  
Author(s):  
Aravind Sundaramurthy ◽  
Vivek Bhaskar Kote ◽  
Noah Pearson ◽  
Gregory M. Boiczyk ◽  
Elizabeth M. McNeil ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Material Properties ◽  
Laboratory Experiments ◽  
Scaling Laws ◽  
Brain Injuries ◽  
Blast Waves ◽  
High Fidelity ◽  
Fe Model ◽  
Cerebral Vasculature ◽  
Biomechanical Responses

Despite years of research, it is still unknown whether the interaction of explosion-induced blast waves with the head causes injury to the human brain. One way to fill this gap is to use animal models to establish “scaling laws” that project observed brain injuries in animals to humans. This requires laboratory experiments and high-fidelity mathematical models of the animal head to establish correlates between experimentally observed blast-induced brain injuries and model-predicted biomechanical responses. To this end, we performed laboratory experiments on Göttingen minipigs to develop and validate a three-dimensional (3-D) high-fidelity finite-element (FE) model of the minipig head. First, we performed laboratory experiments on Göttingen minipigs to obtain the geometry of the cerebral vasculature network and to characterize brain-tissue and vasculature material properties in response to high strain rates typical of blast exposures. Next, we used the detailed cerebral vasculature information and species-specific brain tissue and vasculature material properties to develop the 3-D high-fidelity FE model of the minipig head. Then, to validate the model predictions, we performed laboratory shock-tube experiments, where we exposed Göttingen minipigs to a blast overpressure of 210 kPa in a laboratory shock tube and compared brain pressures at two locations. We observed a good agreement between the model-predicted pressures and the experimental measurements, with differences in maximum pressure of less than 6%. Finally, to evaluate the influence of the cerebral vascular network on the biomechanical predictions, we performed simulations where we compared results of FE models with and without the vasculature. As expected, incorporation of the vasculature decreased brain strain but did not affect the predictions of brain pressure. However, we observed that inclusion of the cerebral vasculature in the model changed the strain distribution by as much as 100% in regions near the interface between the vasculature and the brain tissue, suggesting that the vasculature does not merely decrease the strain but causes drastic redistributions. This work will help establish correlates between observed brain injuries and predicted biomechanical responses in minipigs and facilitate the creation of scaling laws to infer potential injuries in the human brain due to exposure to blast waves.

Predicting the High Speed Cutting Process of Titanium Alloy by Finite Element Method

2011 ◽  
Author(s):  
Xiangqin Zhang ◽  
Xueping Zhang ◽  
A. K. Srivastava
Keyword(s):  
Finite Element ◽  
Cutting Forces ◽  
High Speed ◽  
Cutting Temperature ◽  
Chip Morphology ◽  
Cutting Process ◽  
Fe Model ◽  
Dry Cutting ◽  
Friction Coefficients ◽  
Machining Conditions

To predict the cutting forces and cutting temperatures accurately in high speed dry cutting Ti-6Al-4V alloy, a Finite Element (FE) model is established based on ABAQUS. The tool-chip-work friction coefficients are calculated analytically using the measured cutting forces and chip morphology parameter obtained by conducting the orthogonal (2-D) machining tests. It reveals that the friction coefficients between tool-work are 3∼7 times larger than that between tool-chip, and the friction coefficients of tool-chip-work vary with feed rates. The analysis provides a better reference for the tool-work-chip friction coefficients than that given by literature empirically regardless of machining conditions. The FE model is capable of effectively simulating the high speed dry cutting process of Ti-6Al-4V alloy based on the modified Johnson-Cook model and tool-work-chip friction coefficients obtained analytically. The FE model is further validated in terms of predicted forces and the chip morphology. The predicted cutting force, thrust force and resultant force by the FE model agree well with the experimentally measured forces. The errors in terms of the predicted average value of chip pitch and the distance between chip valley and chip peak are smaller. The FE model further predicts the cutting temperature and residual stresses during high speed dry cutting of Ti-6Al-4V alloy. The maximum tool temperatures exist along the round tool edge, and the residual stress profiles along the machined surface are hook-shaped regardless of machining conditions.

Splash formation by spherical drops

2001 ◽  
Vol 427 ◽  
pp. 73-105 ◽  
Author(s):  
LIOW JONG LENG
Keyword(s):  
High Resolution ◽  
Quantitative Data ◽  
Water Surface ◽  
High Speed ◽  
Scaling Laws ◽  
Capillary Wave ◽  
Water Drop ◽  
Qualitative And Quantitative ◽  
High Resolution Images ◽  
The Impact

The impact of a spherical water drop onto a water surface has been studied experimentally with the aid of a 35 mm drum camera giving high-resolution images that provided qualitative and quantitative data on the phenomena. Scaling laws for the time to reach maximum cavity sizes have been derived and provide a good fit to the experimental results. Transitions between the regimes for coalescence-only, the formation of a high-speed jet and bubble entrapment have been delineated. The high-speed jet was found to occur without bubble entrapment. This was caused by the rapid retraction of the trough formed by a capillary wave converging to the centre of the cavity base. The converging capillary wave has a profile similar to a Crapper wave. A plot showing the different regimes of cavity and impact drop behaviour in the Weber–Froude number-plane has been constructed for Fr and We less than 1000.

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