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.

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.

Effects of infill patterns on the strength and stiffness of 3D printed topologically optimized geometries

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nadim S. Hmeidat ◽  
Bailey Brown ◽  
Xiu Jia ◽  
Natasha Vermaak ◽  
Brett Compton
Keyword(s):  
Material Properties ◽  
Failure Modes ◽  
Mechanical Anisotropy ◽  
Failure Behavior ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Orthotropic Composite ◽  
Material Extrusion ◽  
Specific Material ◽  
Strength And Stiffness

Purpose Mechanical anisotropy associated with material extrusion additive manufacturing (AM) complicates the design of complex structures. This study aims to focus on investigating the effects of design choices offered by material extrusion AM – namely, the choice of infill pattern – on the structural performance and optimality of a given optimized topology. Elucidation of these effects provides evidence that using design tools that incorporate anisotropic behavior is necessary for designing truly optimal structures for manufacturing via AM. Design/methodology/approach A benchmark topology optimization (TO) problem was solved for compliance minimization of a thick beam in three-point bending and the resulting geometry was printed using fused filament fabrication. The optimized geometry was printed using a variety of infill patterns and the strength, stiffness and failure behavior were analyzed and compared. The bending tests were accompanied by corresponding elastic finite element analyzes (FEA) in ABAQUS. The FEA used the material properties obtained during tensile and shear testing to define orthotropic composite plies and simulate individual printed layers in the physical specimens. Findings Experiments showed that stiffness varied by as much as 22% and failure load varied by as much as 426% between structures printed with different infill patterns. The observed failure modes were also highly dependent on infill patterns with failure propagating along with printed interfaces for all infill patterns that were consistent between layers. Elastic FEA using orthotropic composite plies was found to accurately predict the stiffness of printed structures, but a simple maximum stress failure criterion was not sufficient to predict strength. Despite this, FE stress contours proved beneficial in identifying the locations of failure in printed structures. Originality/value This study quantifies the effects of infill patterns in printed structures using a classic TO geometry. The results presented to establish a benchmark that can be used to guide the development of emerging manufacturing-oriented TO protocols that incorporate directionally-dependent, process-specific material properties.

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.

Application of Multiscale Cohesive Zone Model to Simulate Fracture in Polycrystalline Solids

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Jing Qian ◽  
Shaofan Li
Keyword(s):  
Material Properties ◽  
Cohesive Zone ◽  
High Speed ◽  
Cohesive Zone Model ◽  
Small Scale ◽  
Zone Model ◽  
Transgranular Fracture ◽  
Spall Fracture ◽  
High Speed Impact ◽  
Polycrystalline Solids

In this work, we apply the multiscale cohesive method (Zeng and Li, 2010, “A Multiscale Cohesive Zone Model and Simulations of Fracture,” Comput. Methods Appl. Mech. Eng., 199, pp. 547–556) to simulate fracture and crack propagations in polycrystalline solids. The multiscale cohesive method uses fundamental principles of colloidal physics and micromechanics homogenization techniques to link the atomistic binding potential with the mesoscale material properties of the cohesive zone and hence, the method can provide an effective means to describe heterogeneous material properties at a small scale by taking into account the effect of inhomogeneities such as grain boundaries, bimaterial interfaces, slip lines, and inclusions. In particular, the depletion potential of the cohesive interface is made consistent with the atomistic potential inside the bulk material and it provides microstructure-based interface potentials in both normal and tangential directions with respect to finite element boundary separations. Voronoi tessellations have been utilized to generate different randomly shaped microstructure in studying the effect of polycrystalline grain morphology. Numerical simulations on crack propagation for various cohesive strengths are presented and it demonstrates the ability to capture the transition from the intergranular fracture to the transgranular fracture. A convergence test is conducted to study the possible size-effect of the method. Finally, a high-speed impact example is reported. The example demonstrates the advantages of multiscale cohesive method in simulating the spall fracture under high-speed impact loads.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

Materials technology: Innovations and progress

Impact ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. 52-53
Author(s):  
Lucy Sharp
Keyword(s):  
Material Properties ◽  
New Materials ◽  
Medical Problems ◽  
Technology Innovations ◽  
Societal Challenges ◽  
New Material ◽  
Innovative Materials ◽  
The Creation ◽  
Novel Applications

Materials technology is a constantly evolving discipline, with new materials leading to novel applications. For example, new material properties arise from combining different materials into composites. Researching materials can help solve societal challenges, with the creation of innovative materials resulting in breakthroughs in overcoming hurdles facing humankind, including energy challenges and medical problems. Innovative materials breathe new life into industries and spur on scientific and technological discovery.

scholarly journals A numerical approach for the modelling of forming limits in hot incremental forming of AZ31 magnesium alloy

2021 ◽  
Author(s):  
Davide Campanella ◽  
Gianluca Buffa ◽  
Ernesto Lo Valvo ◽  
Livan Fratini
Keyword(s):  
Room Temperature ◽  
Incremental Forming ◽  
Material Model ◽  
Numerical Approach ◽  
Forming Limit ◽  
Material Strength ◽  
Wall Angle ◽  
Analytical Expression ◽  
The Poor ◽  
Specific Material

AbstractMagnesium alloys, because of their good specific material strength, can be considered attractive by different industry fields, as the aerospace and the automotive one. However, their use is limited by the poor formability at room temperature. In this research, a numerical approach is proposed in order to determine an analytical expression of material formability in hot incremental forming processes. The numerical model was developed using the commercial software ABAQUS/Explicit. The Johnson-Cook material model was used, and the model was validated through experimental measurements carried out using the ARAMIS system. Different geometries were considered with temperature varying in a range of 25–400 °C and wall angle in a range of 35–60°. An analytical expression of the fracture forming limit, as a function of temperature, was established and finally tested with a different geometry in order to assess the validity.

Sign in / Sign up

Export Citation Format

Share Document