Applying Membrane Mode Enhanced Cohesive Zone Elements on Tailored Forming Components

Forming of hybrid bulk metal components might include severe membrane mode deformation of the joining zone. This effect is not reflected by common Traction Separation Laws used within Cohesive Zone Elements that are usually applied for the simulation of joining zones. Thus, they cannot capture possible damage of the joining zone under these conditions. Membrane Mode Enhanced Cohesive Zone Elements fix this deficiency. This novel approach can be implemented in finite elements. It can be used within commercial codes where an implementation as a material model is beneficial as this simplifies model preparation with the existing GUIs. In this contribution, the implementation of Membrane Mode Enhanced Cohesive Zone Elements as a material model is presented within MSC Marc along with simulations showing the capabilities of this approach.

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Comparison of cohesive zone elements and smoothed particle hydrodynamics for failure prediction of single lap adhesive joints

The Journal of Adhesion ◽

10.1080/00218464.2015.1081819 ◽

2015 ◽

Vol 93 (6) ◽

pp. 444-460 ◽

Cited By ~ 14

Author(s):

A. Mubashar ◽

I. A. Ashcroft

Keyword(s):

Smoothed Particle Hydrodynamics ◽

Cohesive Zone ◽

Failure Prediction ◽

Adhesive Joints ◽

Particle Hydrodynamics ◽

Smoothed Particle ◽

Cohesive Zone Elements

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Considering multiple process observables to determine material model parameters for FE-cutting simulations

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-021-06845-6 ◽

2021 ◽

Author(s):

Marvin Hardt ◽

Thomas Bergs

Keyword(s):

Chip Thickness ◽

Material Model ◽

Experimental Investigations ◽

Model Parameters ◽

Inverse Approach ◽

Local Material ◽

Novel Approach ◽

Validation Parameters ◽

Multiple Process ◽

Cutting Simulations

AbstractAnalyzing the chip formation process by means of the finite element method (FEM) is an established procedure to understand the cutting process. For a realistic simulation, different input models are required, among which the material model is crucial. To determine the underlying material model parameters, inverse methods have found an increasing acceptance within the last decade. The calculated model parameters exhibit good validity within the domain of investigation, but suffer from their non-uniqueness. To overcome the drawback of the non-uniqueness, the literature suggests either to enlarge the domain of experimental investigations or to use more process observables as validation parameters. This paper presents a novel approach merging both suggestions: a fully automatized procedure in conjunction with the use of multiple process observables is utilized to investigate the non-uniqueness of material model parameters for the domain of cutting simulations. The underlying approach is two-fold: Firstly, the accuracy of the evaluated process observables from FE simulations is enhanced by establishing an automatized routine. Secondly, the number of process observables that are considered in the inverse approach is increased. For this purpose, the cutting force, cutting normal force, chip temperature, chip thickness, and chip radius are taken into account. It was shown that multiple parameter sets of the material model can result in almost identical simulation results in terms of the simulated process observables and the local material loads.

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Damage Accumulation and Life-Prediction Models for SnAgCu Leadfree Electronics Under Shock-Impact

ASME 2009 InterPACK Conference, Volume 1 ◽

10.1115/interpack2009-89307 ◽

2009 ◽

Cited By ~ 1

Author(s):

Pradeep Lall ◽

Sandeep Shantaram ◽

Arjun Angral ◽

Mandar Kulkarni ◽

Jeff Suhling

Keyword(s):

Digital Image Correlation ◽

Digital Image ◽

Thermal Aging ◽

Cohesive Zone ◽

Life Prediction ◽

Failure Modes ◽

Damage Index ◽

Image Correlation ◽

Shock Impact ◽

Cohesive Zone Elements

Relative damage-index based on the leadfree interconnect transient strain history from digital image correlation, explicit finite-elements, cohesive-zone elements, and component’s survivability envelope has been developed for life-prediction of two-leadfree electronic alloy systems. Life prediction of pristine and thermally-aged assemblies, have been investigated. Solder alloy system studied include Sn1Ag0.5Cu, and 96.5Sn3.5Ag. Transient strains during the shock-impact have been measured using digital image correlation in conjunction with high-speed cameras operating at 50,000 fps. Both the board strains and the package strains have been measured in a variety of drop orientations including JEDEC horizontal drop orientation, vertical drop orientation and intermediate drop orientations. In addition the effect of sequential stresses of thermal aging and shock-impact on the failure mechanisms has also been studied. The thermal aging condition used for the study includes 125°C for 100 hrs. The presented methodology addresses the need for life prediction of new lead-free alloy-systems under shock and vibration, which is largely beyond the state of art. Three failure modes have been predicted including interfacial failure at the copper-solder interface, solder-PCB interface, and the solder joint failure. Explicit non-linear finite element models with cohesive-zone elements have been developed and correlated with experimental results. Velocity data from digital image correlation has been used to drive the attachment degrees of freedom of the submodel and extract transient interconnect strain histories. Explicit finite-element sub-modeling has been correlated with the full-field strain in various locations, orientations, on both the package and the board-side. The survivability of the leadfree interconnections under sequential loading (thermal aging and shock-impact) from simulation has been compared with pristine circuit assemblies subjected to shock-impact. Sequential loading changes the failure modes and decreases the drop reliability as compared to the room temperature experimental results. Damage index based survivability envelope is intended for component integration to ensure reliability in harsh environments.

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Assessment of 3D Linear Elastic Masonry-Like Vaulted Structures

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.817.50 ◽

2019 ◽

Vol 817 ◽

pp. 50-56

Author(s):

Deborah Briccola ◽

Matteo Bruggi ◽

Alberto Taliercio

Keyword(s):

Material Model ◽

Equivalent Material ◽

Technical Literature ◽

Linear Elastic ◽

Novel Approach ◽

Out Of Plane ◽

Minimization Procedure ◽

Live Loads ◽

Historical Masonry ◽

No Tension Material

A novel approach is adopted to assess the static behavior of vaulted structures, such as cantilevered masonry stairs, assuming a linear elastic no-tension material model. Masonry is substituted by an equivalent orthotropic material whose elastic properties vary locally and with a negligible stiffness where tensile strain occurs. In order to recover a tension-free state of stress, an energy-based minimization procedure is carried out to establish the distribution and the orientation of the equivalent material for a given compatible load. The capability of the approach in defining purely compressive stress solutions in masonry walls under dead load and both in-plane and out-of-plane live loads has already been assessed. A meaningful application to a cantilevered masonry stair is here presented; the results are in good agreement with those available in the technical literature on historical masonry constructions.

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Modeling machining of particle-reinforced aluminum-based metal matrix composites using cohesive zone elements

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-014-6715-5 ◽

2015 ◽

Vol 78 (5-8) ◽

pp. 1171-1179 ◽

Cited By ~ 36

Author(s):

U. Umer ◽

M. Ashfaq ◽

J. A. Qudeiri ◽

H. M. A. Hussein ◽

S. N. Danish ◽

...

Keyword(s):

Metal Matrix Composites ◽

Cohesive Zone ◽

Metal Matrix ◽

Matrix Composites ◽

Cohesive Zone Elements

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Modelling the Effect of Microstructural Randomness on the Fracture of Composite Laminates with Stochastic Cohesive Zone Elements

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.417-418.13 ◽

2009 ◽

Vol 417-418 ◽

pp. 13-16

Author(s):

Zahid R. Khokhar ◽

Ian A. Ashcroft ◽

Vadim V. Silberschmidt

Keyword(s):

Cohesive Zone ◽

Composite Laminates ◽

Composite Structures ◽

Laminated Composite ◽

Specific Strength ◽

Laminated Composite Structures ◽

Structural Applications ◽

Fibre Reinforced Polymer ◽

Strength And Stiffness ◽

Cohesive Zone Elements

Fibre reinforced polymer composites (FRPCs) are being increasingly used in structural applications where high specific strength and stiffness are required. The performance of FRPCs is affected by multi-mechanism damage evolution under loading which in turn is affected by microstructural stochasticity in the material. This means that the fracture of a FRPC is a stochastic process. However, to date most analyses of these materials have treated them in a deterministic way. In this paper the effect of stochasticity in FRPCs is investigated through the application of cohesive zone elements in which random properties are introduced. These may be termed ‘stochastic cohesive zone elements’ and are used in this paper to investigate the effect of microstructural randomness on the fracture behaviour of cross-ply laminate specimens loaded in tension. It is seen from this investigation that microstructure can significantly affect the macroscopic response of FRPC’s, emphasizing the need to account for microstructural randomness in order to make accurate prediction of the performance of laminated composite structures.

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Development of Delamination in Cross-Ply Laminates: Effect of Microstructure

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.413-414.229 ◽

2009 ◽

Vol 413-414 ◽

pp. 229-236 ◽

Cited By ~ 3

Author(s):

Zahid R. Khokhar ◽

Ian A. Ashcroft ◽

Vadim V. Silberschmidt

Keyword(s):

Random Fields ◽

Cohesive Zone ◽

Effective Properties ◽

Axial Stress ◽

Damage Mechanism ◽

Stress Concentrations ◽

Matrix Cracks ◽

Load Carrying ◽

The Matrix ◽

Cohesive Zone Elements

Various aspects of the effect of microstructural randomness exhibited by carbon fibre-reinforced cross-ply laminates on the delamination damage mechanism is investigated in this paper. In the first part, the matrix cracks with different spacings measured in experiments are simulated using finite elements in order to obtain the levels of degradation and effective properties for a composite beam loaded in bending. The results show significant levels of degradation of obtained effective properties depicting the importance of accounting for the inherent stochasticity in these laminates. In the second part of the paper, initiation of delamination at an interface between 0° and 90° layers due to stress concentrations at tips matrix cracks is simulated for a beam under tension. Stochastic cohesive zone elements with fracture parameters presented as random fields are used to model this interface in a composite. Different values of the axial stress are obtained for initiation of damage for a number of realisations based on this approach. The results emphasize the need to take into consideration the microstructural randomness in fibre-reinforced laminates for adequate predictions of damage and load carrying capacities.

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