The Debond Fracture of Sandwich Plate with Corrugated Core Using Cohesive Zone Element

2012 ◽  
Vol 525-526 ◽  
pp. 117-120
Author(s):  
Guang Ping Zou ◽  
Peng Fei Yang ◽  
Jie Lu ◽  
Yong Gui Li
Keyword(s):  
Tensile Test ◽  
Cohesive Zone ◽  
Strain Energy ◽  
Sandwich Plate ◽  
Strain Energy Release ◽  
Element Model ◽  
Mode I Fracture Toughness ◽  
The Face ◽  
Open Displacement ◽  
Cohesive Element Model

In this paper, flatwise tensile test (FWT) and modified double cantilever beam (DCB) experiment were conducted to investigated the debond fracture of sandwich plate with corrugated core. In the experiment, the crack always stays at the face/core interfacial. Tensile bond strength of face core can be given from the flatwise tensile test and we can get the mode I fracture toughness GIC from DCB tests. It is found that the trends of curves change greatly at the beginning, with the propagation of crack, load against open displacement curves change smoothly. In order to simulate the face/core failure of sandwich plate with corrugated core, the cohesive element model is used. Tensile strength and strain energy release rate measured by the experiments presented in this paper are used in as parameters for simulation of the debond fracture. By comparing with the experiment results, the model can express the face/core failure of sandwich plate with corrugated core validly.

scholarly journals A numerical analysis of skin–PPE interaction to prevent facial tissue injury

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rikeen D. Jobanputra ◽  
Jack Hayes ◽  
Sravani Royyuru ◽  
Marc A. Masen
Keyword(s):  
Strain Energy Density ◽  
Strain Energy ◽  
Tissue Injury ◽  
Soft Materials ◽  
Element Model ◽  
Healthcare Systems ◽  
Skin Injury ◽  
Energy Density Distribution ◽  
The World ◽  
The Face

AbstractThe use of close-fitting PPE is essential to prevent exposure to dispersed airborne matter, including the COVID-19 virus. The current pandemic has increased pressure on healthcare systems around the world, leading to medical professionals using high-grade PPE for prolonged durations, resulting in device-induced skin injuries. This study focuses on computationally improving the interaction between skin and PPE to reduce the likelihood of discomfort and tissue damage. A finite element model is developed to simulate the movement of PPE against the face during day-to-day tasks. Due to limited available data on skin characteristics and how these vary interpersonally between sexes, races and ages, the main objective of this study was to establish the effects and trends that mask modifications have on the resulting subsurface strain energy density distribution in the skin. These modifications include the material, geometric and interfacial properties. Overall, the results show that skin injury can be reduced by using softer mask materials, whilst friction against the skin should be minimised, e.g. through use of micro-textures, humidity control and topical creams. Furthermore, the contact area between the mask and skin should be maximised, whilst the use of soft materials with incompressible behaviour (e.g. many elastomers) should be avoided.

scholarly journals The influence of edge effects on crack propagation in snow stability tests

2014 ◽  
Vol 8 (1) ◽  
pp. 229-257
Author(s):  
E. H. Bair ◽  
R. Simenhois ◽  
A. van Herwijnen ◽  
K. Birkeland
Keyword(s):  
Crack Propagation ◽  
Strain Energy ◽  
Wave Speed ◽  
Strain Energy Release Rate ◽  
Field Tests ◽  
Strain Energy Release ◽  
Element Model ◽  
Fe Model ◽  
Test Length ◽  
Column Tests

Abstract. Propagation tests are used to assess the likelihood of crack propagation in a snowpack, yet little is known about how test length affects propagation. Guidelines suggest beams with lengths around 1 m for Extended Column Tests (ECTs) and Propagation Saw Tests (PSTs). To examine how test length affects propagation, we performed 163 ECTs and PSTs 1 to 10 m long. On days with full crack propagation in 1.0 to 1.5 m tests, we then made videos of tests 2 to 10 m long. We inserted markers for particle tracking to measure collapse amplitude, collapse wave speed, and wavelength. We also used a finite element model to simulate the strain energy release rate at fixed crack lengths. We find that: (1) the proportion of tests with full propagation decreased with test length; (2) collapse was greater at the ends of the beams than in the centers; (3) collapse amplitudes in the longer tests were consistent with the shorter tests and did not reach a constant value; (4) collapse wavelengths in the longer tests were around 3 m, 2 × greater than what is predicted by the anticrack model. Based on our field tests and FE models, we conclude that the shorter tests fully propagated more frequently because of increased stress concentration from the far edge. The FE model suggests this edge effect occurs for PSTs up to 2 m long or a crack to beam length ratio ≥ 0.20. Our results suggest that ECT and PST length guidelines may need to be revisited.

scholarly journals Influence of Dynamic Loading on Fracture Behaviour of DCB Sandwich Specimen

2019 ◽  
Vol 29 ◽  
pp. 02003 ◽  
Author(s):  
Vyacheslav N. Burlayenko ◽  
Tomasz Sadowski ◽  
Daniel Pietras
Keyword(s):  
Finite Element ◽  
Dynamic Fracture ◽  
Strain Energy ◽  
Fracture Behaviour ◽  
Sandwich Beam ◽  
Strain Energy Release ◽  
Element Model ◽  
Dynamic Finite Element ◽  
Sandwich Specimen ◽  
The Finite Element Model

Numerical simulations of dynamic fracture behaviour of a double cantilever sandwich beam subjected to uneven bending moments in plane conditions are carried out using the dynamic finite element analyses with the ABAQUSTM code. The strain energy release rate was evaluated by means of the finite element model developed within the two-dimensional (2-D) linear elastodynamic theory. This demonstrates the capability and the reliability of the finite element modelling as an extremely useful numerical tool for solving dynamic fracture mechanics problems. Also, the dynamic behaviour of fracture parameters and interface crack progression is discussed.

Application of Virtual Crack Close Technique in the Static Crack Growth Based on Strain Energy Release Rate Criterion

2012 ◽  
Vol 204-208 ◽  
pp. 3002-3008
Author(s):  
Chen Cheng ◽  
Shui Wan ◽  
Zhen Wen Jang
Keyword(s):  
Energy Release Rate ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Strain Energy ◽  
Strain Energy Release Rate ◽  
Strain Energy Release ◽  
Element Model ◽  
Energy Release Rate Criterion ◽  
Rate Criterion

A method to simulate the crack growth, according to the strain energy release rate criterion, with the virtual crack close technique, is studied. The virtual crack close technique is used to calculate the strain energy release rate. To achieve the virtual crack close technique, in the FEA software of ANSYS, COMBIN14 spring elements are adopted to set up the finite element model. Then this method to simulate the crack growth is validated by three crack growth problems. This method is a useful and accurate numerical simulation method.

A Numerical Analysis of Skin-PPE Interaction to Prevent Facial Tissue Injury

2021 ◽  
Author(s):  
Rikeen D. Jobanputra ◽  
Jack Hayes ◽  
Sravani Royyuru ◽  
Marc A. Masen
Keyword(s):  
Strain Energy Density ◽  
Strain Energy ◽  
Tissue Injury ◽  
Soft Materials ◽  
Element Model ◽  
Medical Professionals ◽  
High Grade ◽  
Skin Injury ◽  
Energy Density Distribution ◽  
The Face

Abstract The use of close-fitting PPE is essential to prevent exposure to dispersed airborne matter, including the COVID-19 virus. The current pandemic has increased pressure on the healthcare system, leading to medical professionals using high-grade PPE for prolonged times, resulting in device-insduced skin injuries. This study focuses on computationally improving the interaction between skin and PPE to reduce the likelihood of discomfort and tissue damage. A finite element model is developed to simulate the movement of PPE against the face during day-to-day tasks. Due to limited available data on skin characteristics and how these vary interpersonally between sexes, races and ages, the main objective of this study was to establish the effects and trends that mask modifications have on the resulting subsurface strain energy density distribution in the skin. These modifications include the material, geometry and interfacial properties. Overall, the results show that skin injury can be reduced by using softer mask materials, whilst friction against the skin should be minimised, e.g. through use of micro-textures, humidity control and topical creams. Furthermore, the contact area between the mask and skin should be maximised, whilst the use of soft materials with incompressible behaviours (e.g. most elastomers) should be avoided.

A Cohesive Zone Model to Predict Dynamic Tearing of Rubber

2015 ◽  
Vol 43 (4) ◽  
pp. 297-324 ◽  
Author(s):  
Bo Li ◽  
Michelle S. Hoo Fatt
Keyword(s):  
Crack Growth ◽  
Cohesive Zone ◽  
Strain Energy ◽  
Cohesive Zone Model ◽  
Pure Shear ◽  
Strain Energy Release ◽  
Zone Model ◽  
Element Analysis ◽  
Critical Crack ◽  
Damage Initiation

ABSTRACT Tire failures, such as tread separation and sidewall zipper fracture, occur when internal flaws (cracks) nucleate and grow to a critical size as result of fatigue or cyclic loading. Sudden and catastrophic rupture takes place at this critical crack size because the strain energy release rate exceeds the tear energy of the rubber in the tire. The above-mentioned tire failures can lead to loss of vehicle stability and control, and it is important to develop predictive models and computational tools that address this problem. The objective of this article was to develop a cohesive zone model for rubber to numerically predict crack growth in a rubber component under dynamic tearing. The cohesive zone model for rubber was embedded into the material constitutive equation via a user-defined material subroutine (VUMAT) of ABAQUS. It consisted of three parts: (1) hyperviscoelastic behavior before damage, (2) damage initiation based on the critical strain energy density, and (3) hyperviscoelastic behavior after damage initiation. Crack growth in the tensile strip and pure shear specimens was simulated in ABAQUS Explicit, and good agreement was reported between finite element analysis predictions and test results.

scholarly journals Interlocking birch plywood structures

2021 ◽  
pp. 095605992110222
Author(s):  
Chrysl A Aranha ◽  
Markus Hudert ◽  
Gerhard Fink
Keyword(s):  
High Surface ◽  
Surface Hardness ◽  
Experimental Tests ◽  
Digital Fabrication ◽  
Element Model ◽  
Component Level ◽  
Geometrical Properties ◽  
Stiffness Properties ◽  
The Face ◽  
Strength And Stiffness

Interlocking Particle Structures (IPS) are geometrically stable assemblies, usually fabricated from plate type elements that are interconnected by slotted joints. IPS are demountable and their components have the potential to be used and reused in different structures and configurations. This paper explores the applicability of birch plywood panels, which are characterized by a high surface hardness, for this type of structural system. Experimental tests were conducted to determine the mechanical properties of birch plywood plates. Moreover, IPS connections with different geometrical properties were investigated for two different load exposures: bending and rotation. The characteristics under bending exposure are influenced by the orientation of the face-veneers. For the rotational load exposure, very small strength and stiffness properties have been identified. A linear elastic finite element model is presented that shows a wide agreement with the test results. The study serves as an initial probe into the performance of IPS structures at the component level. Various aspects that are relevant for the design of IPS, such as the assembly, the accuracy and challenges regarding digital fabrication, the durability, and the structural performance are discussed.

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