Indentation Simulation of Ovariectomized Sheep Bone Using a Viscoelastic/Plastic Damage Model

2011 ◽  
Author(s):  
Yang Zhao ◽  
Timothy C. Ovaert
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Trabecular Bone ◽  
Mechanical Loading ◽  
Standard Method ◽  
Light Microscope ◽  
Damage Accumulation ◽  
Damage Model ◽  
Plastic Damage ◽  
Material Discontinuities

Indentation techniques have become a standard method to assess the mechanical properties of numerous materials. In recent years, nanoindentation of bone has been used to extract the mechanical behavior at the level of osteons and lamellae. Under a transmitted light microscope, small microcracks can be observed in cortical bone, and breakage of trabeculea can be observed in trabecular bone. These cracks are implicated in physiological phenomena including stress fractures, bone remodeling, and adaptation. Together, these material discontinuities can be considered as damage. Damage accumulation of bone is generated through daily mechanical loading, and then recovered during remodeling. For bone indentation modeling, even though pre-existing damage may be neglected in most cases, new damage can also be produced during the process of testing. Thus, damage accumulation needs to be considered when establishing a nanomechanical bone model.

Simulation of Nano- and Micro-Indentation Behavior of Bone via a Plastic-Damage Model

2008 ◽  
Author(s):  
Jingzhou Zhang ◽  
Timothy Ovaert
Keyword(s):  
Mechanical Properties ◽  
Damage Model ◽  
Maximum Load ◽  
High Load ◽  
Material Degradation ◽  
Bone Specimen ◽  
Naturally Occurring ◽  
Plastic Damage ◽  
Indent Depth ◽  
Micro Indentation

Damage results in a loss of material continuity, which distinguishes it from other types of material degradation. The loss of continuity can have an adverse effect on mechanical properties, and may be manifested in the form of cracks and/or voids. Bone tissue, as a composite material, contains voids and other non-homogeneities that are naturally occurring and distinct from damage. However, when subjected to mechanical loading, such as indentation, further damage accumulation may occur. Figure 1 shows a cross-section of a bovine cortical bone specimen after high-load conical indentation to a depth of 300 μm, resulting in a large permanently deformed region. Nanoindentation, using a Berkovich tip at 10 mN maximum load, was then performed at numerous locations within three defined damage “zones”. Zone 1 is adjacent to the bottom of the indent, defined at 25% of the maximum indent depth. Zones 2 and 3 extend further away, both scaled as a function of the indentation depth, d. Figure 2 shows the variation in Young’s modulus in the three damage zones, averaged over approximately 25 indents per zone. The data suggest that local changes in mechanical properties may occur as a result of compaction of voids or cracks. The purpose of this work, therefore, is to investigate the application of a plastic-damage model for simulation of bone nano- and micro-scale indentation behavior.

scholarly journals A 3D trabecular bone homogenization technique

2020 ◽  
Vol 22 (3) ◽  
Author(s):  
Marco C. Marques ◽  
Jorge Belinha ◽  
António F. Oliveira ◽  
Maria Cristinha M. Cespedes ◽  
Renato M. Natal Jorge
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Trabecular Bone ◽  
Multiple Scales ◽  
Bone Adaptation ◽  
Computationally Efficient ◽  
Micro Scale ◽  
Special Cases ◽  
Homogeneous Models ◽  
Time Required

Purpose: Bone is a hierarchical material that can be characterized from the microscale to macroscale. Multiscale models make it possible to study bone remodeling, inducing bone adaptation by using information of bone multiple scales. This work proposes a computationally efficient homogenization methodology useful for multiscale analysis. This technique is capable to define the homogenized microscale mechanical properties of the trabecular bone highly heterogeneous medium. Methods: In this work, a morphology - based fabric tensor and a set of anisotropic phenomenological laws for bone tissue was used, in order to define the bone micro-scale mechanical properties. To validate the developed methodology, several examples were performed in order to analyze its numerical behavior. Thus, trabecular bone and fabricated benchmarks patches (representing special cases of trabecular bone morphologies) were analyzed under compression. Results: The results show that the developed technique is robust and capable to provide a consistent material homogenization, indicating that the homogeneous models were capable to accurately reproduce the micro-scale patch mechanical behavior. Conclusions: The developed method has shown to be robust, computationally less demanding and enabling the authors to obtain close results when comparing the heterogeneous models with equivalent homogenized models. Therefore, it is capable to accurately predict the micro-scale patch mechanical behavior in a fraction of the time required by classic homogenization techniques.

scholarly journals Data-Driven Damage Model Based on Nondestructive Evaluation

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
Konstantinos P. Baxevanakis ◽  
Brian Wisner ◽  
Sara Schlenker ◽  
Harsh Baid ◽  
Antonios Kontsos
Keyword(s):  
Aluminum Alloy ◽  
Mechanical Behavior ◽  
Nondestructive Evaluation ◽  
Damage Accumulation ◽  
Mechanical Response ◽  
Damage Model ◽  
Experimental Information ◽  
Remaining Useful Life ◽  
Data Driven ◽  
Optical Methods

A computational damage model, which is driven by material, mechanical behavior, and nondestructive evaluation (NDE) data, is presented in this study. To collect material and mechanical behavior damage data, an aerospace grade precipitate-hardened aluminum alloy was mechanically loaded under monotonic conditions inside a scanning electron microscope, while acoustic and optical methods were used to track the damage accumulation process. In addition, to obtain experimental information about damage accumulation at the laboratory scale, a set of cyclic loading experiments was completed using three-point bending specimens made out of the same aluminum alloy and by employing the same nondestructive methods. The ensemble of recorded data for both cases was then used in a postprocessing scheme based on outlier analysis to form damage progression curves, which were subsequently used as custom damage laws in finite element (FE) simulations. Specifically, a plasticity model coupled with stiffness degradation triggered by the experimentally defined damage curves was used in custom subroutines. The results highlight the effect of the data-driven damage model on the simulated mechanical response of the geometries considered and provide an information workflow that is capable of coupling experiments with simulations that can be used for remaining useful life (RUL) estimations.

scholarly journals Mechanical Loading Synergistically Increases Trabecular Bone Volume and Improves Mechanical Properties in the Mouse when BMP Signaling Is Specifically Ablated in Osteoblasts

PLoS ONE ◽  
2015 ◽  
Vol 10 (10) ◽  
pp. e0141345 ◽  
Author(s):  
Ayaka Iura ◽  
Erin Gatenby McNerny ◽  
Yanshuai Zhang ◽  
Nobuhiro Kamiya ◽  
Margaret Tantillo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Trabecular Bone ◽  
Mechanical Loading ◽  
Bone Volume ◽  
Bmp Signaling ◽  
Trabecular Bone Volume

A Semi-Analytical Plastic-Damage Model for Nanoindentation Contact Mechanics

2009 ◽  
Author(s):  
Benjamin Fulleringer ◽  
Timothy C. Ovaert ◽  
Daniel Nelias
Keyword(s):  
Mechanical Properties ◽  
Contact Mechanics ◽  
Damage Model ◽  
Progressive Damage ◽  
Contact Loading ◽  
Ductile Materials ◽  
Plastic Damage

In many applications where cyclic contact loading occurs, the material may undergo progressive damage [1], resulting in a change of its mechanical properties. This can occur in biomaterials such as bone, as well as in brittle and ductile materials such as ceramics and metals, respectively.

MODELISATION DE L'INFLUENCE DU TRAITEMENT THERMIQUE SUR LES PROPRIETES MECANIQUES DES ALLIAGES ALUMINIUM-CUIVRE (Al-Cu)

2015 ◽  
Vol 10 (2) ◽  
pp. 2753-2761
Author(s):  
Saad El Madani ◽  
S. ELHAMZI ◽  
A. IBNLFASSI ◽  
L. ZERROUK ◽  
O. BEN LENDA ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Solidification Process ◽  
Traitement Thermique ◽  
Homogenization Process ◽  
Fundamental Reason ◽  
Segregation Phenomenon ◽  
Proprietes Mecaniques ◽  
Cooling Velocity ◽  
Copper Effect

In order to master and improve the quality and properties of the final products, the major industrial challenge lies in the possibility of controlling the morphology, size of microstructures that reside within the molded pieces, as well as their defects; this is the fundamental reason according to which we are more and more interested in mastering the growth and germination of such alloys, as well as the developing structures, at the time of solidification process. The modeling reveals as a valuable aid in the mastery of the formation of such heterogeneousness: segregation cells that are incompatible with industrial requirements.   The whole work focuses upon the modeling of the segregation phenomenon of the four hypoeutectic alloys, Al1%Cu, Al2%Cu, Al3%Cu et Al4%Cu, as well as the copper effect upon certain mechanical properties of aluminum. Usually, the microstructure and mechanical behavior of such alloys as Al-Cu are directly influenced by some parameters such as composition, cooling velocity and homogenization process.

Why is it necessary to use a damage model to simulate the mechanical behavior of concrete under drying and leaching?

2010 ◽  
Vol 14 (6-7) ◽  
pp. 923-935
Author(s):  
Thomas Rougelot ◽  
Cheng Peng ◽  
Nicolas Burlion ◽  
Dominique Bernard
Keyword(s):  
Mechanical Behavior ◽  
Damage Model

scholarly journals Experimental and Numerical Evaluation of Mechanical Properties of 3D-Printed Stainless Steel 316L Lattice Structures

2021 ◽  
Author(s):  
M. Carraturo ◽  
G. Alaimo ◽  
S. Marconi ◽  
E. Negrello ◽  
E. Sgambitterra ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Mechanical Behavior ◽  
Numerical Simulations ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Lattice Structures ◽  
Stainless Steel 316L ◽  
Research Attention ◽  
Octet Truss

AbstractAdditive manufacturing (AM), and in particular selective laser melting (SLM) technology, allows to produce structural components made of lattice structures. These kinds of structures have received a lot of research attention over recent years due to their capacity to generate easy-to-manufacture and lightweight components with enhanced mechanical properties. Despite a large amount of work available in the literature, the prediction of the mechanical behavior of lattice structures is still an open issue for researchers. Numerical simulations can help to better understand the mechanical behavior of such a kind of structure without undergoing long and expensive experimental campaigns. In this work, we compare numerical and experimental results of a uniaxial tensile test for stainless steel 316L octet-truss lattice specimen. Numerical simulations are based on both the nominal as-designed geometry and the as-build geometry obtained through the analysis of µ-CT images. We find that the use of the as-build geometry is fundamental for an accurate prediction of the mechanical behavior of lattice structures.

scholarly journals Decoupling of Mechanical and Transport Properties in Organogels via Solvent Variation

Gels ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 61
Author(s):  
Kenneth P. Mineart ◽  
Cameron Hong ◽  
Lucas A. Rankin
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Transdermal Drug Delivery ◽  
Triblock Copolymer ◽  
Polymer Concentration ◽  
Mineral Oil ◽  
Solute Diffusion ◽  
Oil Viscosity ◽  
Chain Entanglement ◽  
Mineral Oils

Organogels have recently been considered as materials for transdermal drug delivery media, wherein their transport and mechanical properties are among the most important considerations. Transport through organogels has only recently been investigated and findings highlight an inextricable link between gels’ transport and mechanical properties based upon the formulated polymer concentration. Here, organogels composed of styrenic triblock copolymer and different aliphatic mineral oils, each with a unique dynamic viscosity, are characterized in terms of their quasi-static uniaxial mechanical behavior and the internal diffusion of two unique solute penetrants. Mechanical testing results indicate that variation of mineral oil viscosity does not affect gel mechanical behavior. This likely stems from negligible changes in the interactions between mineral oils and the block copolymer, which leads to consistent crosslinked network structure and chain entanglement (at a fixed polymer concentration). Conversely, results from diffusion experiments highlight that two penetrants—oleic acid (OA) and aggregated aerosol-OT (AOT)—diffuse through gels at a rate inversely proportional to mineral oil viscosity. The inverse dependence is theoretically supported by the hydrodynamic model of solute diffusion through gels. Collectively, our results show that organogel solvent variation can be used as a design parameter to tailor solute transport through gels while maintaining fixed mechanical properties.

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