Department of Mechanical Engineering

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https://hdl.handle.net/11693/13680

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Open Access
On-chip flow rate sensing via membrane deformation and bistability probed by microwave resonators
(Springer Link, 8-04-2023) Seçme, Arda; Pisheh, Hadi Sedaghat; Tefek, Uzay; Uslu, H. Dilara; Küçükoğlu, Berk; Alataş, Ceren; Kelleci, Mehmet; Hanay, Mehmet Selim; Seçme, Arda; Pisheh, Hadi Sedaghat; Tefek, Uzay; Uslu, H. Dilara; Küçükoğlu, Berk; Alataş, Ceren; Kelleci, Mehmet; Hanay, Mehmet Selim
Precise monitoring of fluid flow rates constitutes an integral problem in various lab-on-a-chip applications. While off-chip flow sensors are commonly used, new sensing mechanisms are being investigated to address the needs of increasingly complex lab-on-a-chip platforms which require local and non-intrusive flow rate sensing. In this regard, the deformability of microfluidic components has recently attracted attention as an on-chip sensing mechanism. To develop an on-chip flow rate sensor, here we utilized the mechanical deformations of a 220 nm thick Silicon Nitride membrane integrated with the microfluidic channel. Applied pressure and fluid flow induce different modes of deformations on the membrane, which are electronically probed by an integrated microwave resonator. The flow changes the capacitance, and in turn resonance frequency, of the microwave resonator. By tracking the resonance frequency, liquid flow was probed with the device. In addition to responding to applied pressure by deflection, the membrane also exhibits periodic pulsation motion under fluid flow at a constant rate. The two separate mechanisms, deflection and pulsation, constitute sensing mechanisms for pressure and flow rate. Using the same device architecture, we also detected pressure-induced deformations by a gas to draw further insight into the sensing mechanism of the membrane. Flow rate measurements based on the deformation and instability of thin membranes demonstrate the transduction potential of microwave resonators for fluid–structure interactions at micro- and nanoscales.
Open Access
High resolution dielectric characterization of single cells and microparticles using integrated microfluidic microwave sensors
(Institute of Electrical and Electronics Engineers, 2023-03-01) Seçme, Arda; Tefek, Uzay; Sarı, Burak; Pisheh, Hadi Sedaghat; Uslu, H. Dilara; Akbulut, Özge; Küçükoğlu, Berk; Erdogan, R. Tufan; Alhmoud, Hashim; Şahin, Özgür; Hanay, M. Selim; Seçme, Arda; Tefek, Uzay; Sarı, Burak; Pisheh, Hadi Sedaghat; Uslu, H. Dilara; Akbulut, Özge; Küçükoğlu, Berk; Şahin, Özgür; Alhmoud, Hashim; Erdogan, R. Tufan; Hanay, M. Selim
Microwave sensors can probe intrinsic material properties of analytes in a microfluidic channel at physiologically relevant ion concentrations. While microwave sensors have been used to detect single cells and microparticles in earlier studies, the synergistic use and comparative analysis of microwave sensors with optical microscopy for material classification and size tracking applications have been scarcely investigated so far. Here we combined microwave and optical sensing to differentiate microscale objects based on their dielectric properties. We designed and fabricated two types of planar sensor: a Coplanar Waveguide Resonator (CPW) and a Split-Ring Resonator (SRR). Both sensors possessed sensing electrodes with a narrow gap to detect single cells passing through a microfluidic channel integrated on the same chip. We also show that standalone microwave sensors can track the relative changes in cellular size in real-time. In sensing single 20-micron diameter polystyrene particles, Signal-to-Noise ratio values of approximately 100 for CPW and 70 for SRR sensors were obtained. These findings demonstrate that microwave sensing technology can serve as a complementary technique for single-cell biophysical experiments and microscale pollutant screening.
Open Access
Microfluidics-integrated microwave sensors for single cells size discrimination
(Institute of Electrical and Electronics Engineers, 2021-04-01) Seçme, Arda; Pisheh, Hadi Sedaghat; Uslu, H. Dilara; Akbulut, Özge; Erdoğan, R. Tufan; Hanay, M. Selim; Akbulut, Özge; Erdoğan, R. Tufan; Seçme, Arda; Pisheh, Hadi Sedaghat; Uslu, H. Dilara; Hanay, M. Selim
The size of a cell is one of the most fundamental biophysical parameters it possesses. Traditionally size measurements are done by using optical microscopy and quantitative phase imaging. However, a sensor with higher resolution, high throughput and lower cost is still needed. Here, a novel microfluidics-integrated microwave sensor is demonstrated to characterize single cells in real-time without labelling. Coplanar waveguide resonator is designed with a bowtie-shaped sensing electrodes separated by 50 μm. Cells are transported to sensing region by microfluidic channels and their sizes are measured simultaneously by the microwave sensors and optical microscopy. To enhance the microwave resolution, the microwave resonator is equipped with external heterodyne measurement circuitry detecting each and every cell passing through the sensing region. By comparing quantitative microscopic image analysis with frequency shifts, we show that microwave sensors can effectively measure cellular size. Our results indicate that microfluidics-integrated microwave sensors (MIMS) can be used for detecting.
Open Access
Classification of dielectric microparticles by microwave impedance cytometry
(Cold Spring Harbor Laboratory, 2022-09-28) Hanay, M. Selim; Sarı, Burak; Tefek, Uzay; Hanay, M. Selim; Sarı, Burak; Tefek, Uzay
AbstractCoulter counters and impedance cytometry are commonly used for counting microscopic objects, such as cells and microparticles flowing in a liquid, as well as to obtain their size distribution. However, the ability of these techniques to provide simultaneous material information — via dielectric permittivity measurements — has been limited so far. The challenge stems from the fact that the signals generated by microparticles of identical size, but different material composition, are close to each other. The similarity in impedance signals arises because the material-dependent factor is determined mainly by the volume of aqueous solution displaced by the microparticles, rather than the microparticles themselves. To differentiate between materially distinct particles with similar geometry and size, another measurement mode needs to be implemented. Here, we describe a new microfluidics-based sensor that provides material classification between microparticles with similar sizes by integrating impedance cytometry with microwave resonator sensors on the same chip. While low-frequency impedance cytometry provides the geometric size of particles, the microwave sensor operating at three orders-of-magnitude higher frequency provides their electrical size. By combining these two measurements, the Clausius-Mossotti factors of microparticles can be calculated to serve as a differentiation parameter. In addition to distinguishing dielectric materials from cells and metals, we classified two different dielectric microparticles with similar sizes and electrical characteristics: polystyrene and soda lime glass, with 94% identification accuracy. The proposed technique can serve as an automated monitoring system for quality control of manufactured microparticles and facilitate environmental microplastic screening.
Open Access
On-chip liquid and gas flow rate sensing via membrane deformation and bistability probed by microwave resonators
(Springer, 2022-11-15) Seçme, Arda; Pisheh, Hadi Sedaghat; Uslu, H. Dilara; Tefek, Uzay; Küçükoğlu, Berk; Alataş, Ceren; Kelleci, Mehmet; Hanay, M. Selim; Seçme, Arda; Pisheh, Hadi Sedaghat; Uslu, H. Dilara; Tefek, Uzay; Küçükoğlu, Berk; Alataş, Ceren; Kelleci, Mehmet; Hanay, M. Selim
Abstract Precise monitoring of fluid flow rates constitutes an integral problem in various lab-on-a-chip applications. While off-chip flow sensors are commonly used, new sensing mechanisms are being investigated to address the needs of increasingly complex lab-on-a-chip platforms which require local and non-intrusive flow rate sensing. In this regard, the deformability of microfluidic components has recently attracted attention as an on-chip sensing mechanism. To develop an on-chip flow rate sensor, here we utilized the mechanical deformations of a 220 nm thick Silicon Nitride membrane integrated with the microfluidic channel. Fluid flow induces deformations on the membrane, which is electronically probed by the changes in the capacitance and resonance frequency of an overlapping microwave resonator. By tracking the resonance frequency, both liquid and gas flows were probed with the same device architecture. For liquid flow experiments, a secondary sensing mechanism emerged when it was observed that steady liquid flow induces periodic deformations on the membrane. Here, the period of membrane deformation depends on the flow rate and can again be measured electronically by the microwave sensor. Flow rate measurements based on the deformation and instability of thin membranes demonstrate the transduction potential of microwave resonators for fluid-structure interactions at micro and nanoscales.
Open Access
High resolution dielectric characterization of single cells and microparticles using integrated microfluidic microwave sensors
(Institute of Electrical and Electronics Engineers, 2023-03-01) Seçme, Arda; Tefek, Uzay; Sarı, Burak; Pisheh, Hadi Sedaghat; Uslu, H. Dilara; Akbulut, Özge; Küçükoğlu, Berk; Erdoğan, R. Tufan; Alhmoud, Hashim; Şahin, Özgür; Hanay, M. Selim; Seçme, Arda; Tefek, Uzay; Sarı, Burak; Pisheh, Hadi Sedaghat; Uslu, H. Dilara; Akbulut, Özge; Küçükoğlu, Berk; Erdoğan, R. Tufan; Alhmoud, Hashim; Şahin, Özgür; Hanay, M. Selim
Microwave sensors can probe intrinsic material properties of analytes in a microfluidic channel at physiologically relevant ion concentrations. While microwave sensors have been used to detect single cells and microparticles in earlier studies, the synergistic use and comparative analysis of microwave sensors with optical microscopy for material classification and size tracking applications have been scarcely investigated so far. Here we combined microwave and optical sensing to differentiate microscale objects based on their dielectric properties. We designed and fabricated two types of planar sensor: a Coplanar Waveguide Resonator (CPW) and a Split-Ring Resonator (SRR). Both sensors possessed sensing electrodes with a narrow gap to detect single cells passing through a microfluidic channel integrated on the same chip. We also show that standalone microwave sensors can track the relative changes in cellular size in real-time. In sensing single 20-micron diameter polystyrene particles, Signal-to-Noise ratio values of approximately 100 for CPW and 70 for SRR sensors were obtained. These findings demonstrate that microwave sensing technology can serve as a complementary technique for single-cell biophysical experiments and microscale pollutant screening.
Open Access
Author Correction: Stretchable nanofibers of polyvinylidenefluoride (PVDF)/thermoplastic polyurethane (TPU) nanocomposite to support piezoelectric response via mechanical elasticity (Scientific Reports, (2022), 12, 1, (8335), 10.1038/s41598-022-11465-5)
(Nature Research, 2022-12) Shehata, Nader; Nair, Remya; Boualayan, Rabab; Kandas, Ishac; Masrani, Abdulrazak; Elnabawy, Eman; Omran, Nada; Gamal, Mohammed; Hassanin, Ahmed H.; Masrani, Abdulrazak; Masrani, Abdulrzak
The original version of this Article contained an error in the spelling of the author Abdulrzak Masrani which was incorrectly given as Abdulrazak Masrani. The original Article has been corrected. © The Author(s) 2022.
Open Access
Open system peridynamics
(Springer Science and Business Media Deutschland GmbH, 2022-05-10) Schaller, Emely; Javili, Ali; Steinmann, Paul; Javili, Ali
We propose, for the first time, a thermodynamically consistent formulation for open system (continuum-kinematics-inspired) peridynamics. In contrast to closed system mechanics, in open system mechanics mass can no longer be considered a conservative property. In this contribution, we enhance the balance of mass by a (nonlocal) mass source. To elaborate a thermodynamically consistent formulation, the balances of momentum, energy and entropy need to be reconsidered as they are influenced by the additional mass source. Due to the nonlocal continuum formulation, we distinguish between local and nonlocal balance equations. We obtain the dissipation inequality via a Legendre transformation and derive the structure and constraints of the constitutive expressions based on the Coleman–Noll procedure. For the sake of demonstration, we present an example for a nonlocal mass source that can model the complex process of bone remodelling in peridynamics. In addition, we provide a numerical example to highlight the influence of nonlocality on the material density evolution. © 2022, The Author(s).
Open Access
Microfluidic methods in janus particle synthesis
(Dove Medical Press Ltd, 2022-09-19) Saqib, Muhammad; Tran, Phong A.; Ercan, Batur; Yegan Erdem, Emine; Saqib, Muhammad; Yegan Erdem, Emine
Janus particles have been at the center of attention over the years due to their asymmetric nature that makes them superior in many ways to conventional monophase particles. Several techniques have been reported for the synthesis of Janus particles; however, microfluidic-based techniques are by far the most popular due to their versatility, rapid prototyping, low reagent consumption and superior control over reaction conditions. In this review, we will go through microfluidic-based Janus particle synthesis techniques and highlight how recent advances have led to complex functionalities being imparted to the Janus particles. © 2022 Saqib et al.
Open Access
Modeling pilot-flight control system interactions in the presence of uncertainty
(American Institute of Aeronautics and Astronautics, 2022) Habboush, Abdullah; Yildiz, Yildiray; Habboush, Abdullah; Yildiz, Yildiray
Despite the numerous advances in control theory over the past decades, humans’ versatility in controlling complex systems is still irreplaceable due to their adaptive capabilities. Yet, when it comes to implementing adaptive controllers in piloted applications, unfavorable interactions of human pilots with control systems are observed in certain applications. While several studies exist in the literature that investigate pilot-controller interactions, they are primarily based on linear and fixed dynamics. These studies are useful to study the ideal system behavior, however, they may not be helpful in analyzing uncertainties and failures in system dynamics and the adaptive response of the human operator to these undesired occurrences. In this paper, we fill this gap by proposing a closed-loop system analysis consisting of adaptive dynamics for both the pilot and the flight control system. This analysis can offer guidance in designing adaptive control architectures to enhance safety measures in real-world manned applications.
Open Access
DC-electrokinetic motion of colloidal cylinder(s) in the vicinity of a conducting wall
(Wiley-VCH Verlag GmbH & Co. KGaA, 2022-06) Atay, Atakan; Beşkök, A.; Çetin, Barbaros; Atay, Atakan; Çetin, Barbaros
The boundary effects on DC-electrokinetic behavior of colloidal cylinder(s) in the vicinity of a conducting wall is investigated through a computational model. The contribution of the hydrodynamic drag, gravity, electrokinetic (i.e., electrophoretic and dielectrophoretic), and colloidal forces (i.e., forces due to the electrical double layer and van der Waals interactions) are incorporated in the model. The contribution of electrokinetic and colloidal forces are included by introducing the resulting forces as an external force acting on the particle(s). The colloidal forces are implemented with the prescribed expressions from the literature, and the electrokinetic force is obtained by integrating the corresponding Maxwell stress tensor over the particles' surfaces. The electrokinetic slip-velocity together with the thin electrical double layer assumption is applied on the surfaces. The position and velocity of the particles and the resulting electric and flow fields are obtained and the physical insight for the behavior of the colloidal cylinders are discussed in conjunction with the experimental observations in the literature.
Open Access
Effect of feet failure and control uncertainties on the locomotion of multi-legged miniature robots
(Institute of Electrical and Electronics Engineers, 2022-03-09) Mahkam, Nima; Uğur, Mustafa; Özcan, Onur; Mahkam, Nima; Uğur, Mustafa; Özcan, Onur
This study investigates the effects of control uncertainties and random feet failures on the locomotion of the multi-legged miniature robots. The locomotion analyses results are verified with our modular multi-legged miniature robot with a soft/hybrid body named SMoLBot. A single SMoLBot module is 44.5 mm wide, 16.75 mm long, and 15 mm high with two individually actuated and controlled DC motors. This individual actuation makes it feasible to run with any imaginable gait, making SMoLBot a nice candidate for gait study analyses. The presented locomotion study shows that the effects of control uncertainties and feet failures are highly dependent on the total number of legs and the type of backbone attached to the robot, e.g., increasing the total number of legs or utilizing a rigid backbone on the robot helps the robot to walk faster compared to similar robots with soft backbones or the ones with fewer modules. This study presents a guide to the researchers on the effects of feet failures and control uncertainties on the locomotion of soft/hybrid multi-legged miniature robots.
Open Access
Detecting scalable obstacles using soft sensors in the body of a compliant quadruped
(Institute of Electrical and Electronics Engineers, 2022-01-10) Özbek, Doğa; Yılmaz, Talip Batuhan; Kalın, Mert Ali İhsan; Şentürk, Kutay; Özcan, Onur; Özbek, Doğa; Yılmaz, Talip Batuhan; Kalın, Mert Ali İhsan; Şentürk, Kutay; Özcan, Onur
In soft robotics, one of the trending topics is using soft sensors to have feedback from the robot's body. This is not an easy process to accomplish since the sensors are often nonlinear, so researchers use different methods to generate information from data such as filters, machine learning algorithms, and optimization algorithms. In this paper, we show that, with good electronic and mechanical design, it is possible to use soft sensors for detecting obstacles and distinguishing the scalable obstacles. The demonstration is conducted with an untethered miniature, soft, C-legged robot, M–SQuad, the first modular C-legged quadruped consisting of three modules, which are connected by four soft sensors. In M–SQuad's body design, sensors are utilized as both sensing and structural elements. The modular design of the M–SQuad allows testing different sensor geometries and replacing the malfunctioning parts easily, without the need to refabricate the entire robot. A case study is introduced for demonstration of the robot's capability of detecting obstacles and distinguishing scalable obstacles in a parkour consisting of two obstacles with the heights of 20 mm and 150 mm, respectively. In the case study, M–SQuad can detect an obstacle during locomotion using the coil-spring shaped soft sensors in its body. Moreover, it can distinguish the obstacle is scalable or not after an initial climbing trial. If the obstacle is not scalable, the robot turns back.
Open Access
Fast and predictive heat pipe design and analysis toolbox: H-Pat
(Journal of Thermal Science and Technology, 2022-04-30) Saygan, Samet; Akkuş, Yiğit; Dursunkaya, Zafer; Çetin, Barbaros; Çetin, Barbaros
For the assessment of the thermal performance of heat pipes, a wide range of modeling is available in the literature, ranging from simple capillary limit analyses to comprehensive 3D models. While simplistic models may result in less accurate predictions of heat transfer and operating temperatures, comprehensive models may be computationally expensive. In this study, a universal computational framework is developed for a fast but sufficiently accurate modeling of traditional heat pipes, and an analysis tool based on this framework, named Heat Pipe Analysis Toolbox, in short H-PAT is presented. As a diagnostic tool, H-PAT can predict the fluid flow and heat transfer from a heat pipe under varying heat inputs up to the onset of dryout. During the initial estimation of phase change rates, the solutions of particular thin film phase change models are avoided by specifying an appropriate pattern for the mass flow rate of the liquid along the heat pipe rather than using finite element/volume based methods for the computational domain. With the help of a modular structure, H-PAT can simulate heat pipes with different wick structures as long as an expression for the average liquid velocity and corresponding pressure drop can be introduced. H-PAT is also capable of analyzing heat pipes with variable cross-sections, favorable/unfavorable gravity conditions and utilizes temperature dependent thermo-physical properties at evaporator, condenser and adiabatic regions together with heat input sensitive vapor pressure. In addition, H-PAT performs the computation very fast which also makes it a perfect design tool for researchers and design engineers in the field of thermal management.
Open Access
On continuum modeling of cell aggregation phenomena
(Elsevier, 2022-07-21) Firooz, S.; Kaessmair, S.; Zaburdaev, V.; Javili, Ali; Steinmann, P.; Javili, Ali
Cellular aggregates play a significant role in the evolution of biological systems such as tumor growth, tissue spreading, wound healing, and biofilm formation. Analysis of such biological systems, in principle, includes examining the interplay of cell–cell interactions together with the cell–matrix interaction. These two interaction types mainly drive the dynamics of cellular aggregates which is intrinsically out of equilibrium. Here we propose a non-linear continuum mechanics formulation and the corresponding finite element simulation framework to model the physics of cellular aggregate formation. As an example, we focus in particular on the process of bacterial colony formation as recently studied by Kuan et al. (2021). Thereby we describe the aggregation process as an active phase separation phenomenon. We develop a Lagrangian continuum description of the problem which yields a substantial simplification to the formulations of the governing equations. Due to the presence of spatial Hessian and Laplacian operators, a gradient-enhanced approach is required to incorporate C1 continuity. In addition, a robust and efficient finite element formulation of the problem is provided. Taylor–Hood finite elements are utilized for the implementation to avoid instabilities related to the LBB condition. Finally, through a set of numerical examples, the influence of various parameters on the dynamics of the cellular aggregate formation is investigated. Our proposed methodology furnishes a general framework for the investigation of the rheology and non-equilibrium dynamics of cellular aggregates. © 2022 Elsevier Ltd
Open Access
A nonlocal interface approach to peridynamics exemplified by continuum-kinematics-inspired peridynamics
(John Wiley and Sons Ltd, 2022-08-15) Laurien, Marie; Javili, Ali; Steinmann, Paul; Javili, Ali
In this contribution, we present a novel approach on how to treat material interfaces in nonlocal models based on peridynamics (PD) and in particular continuum-kinematics-inspired peridynamics (CPD), a novel variationally consistent peridynamic formulation. Our method relies on a nonlocal interface where the material subdomains overlap. Within this region, a kinematic coupling of the two constituents is enforced. The contact is purely geometrical as interaction forces act only between points of the same material. We provide a detailed description of the computational implementation within the framework of CPD, that is in principle applicable to all formulations of PD. A variety of numerical examples for modeling bimaterial interfaces illustrate the utility of the technique for both two-dimensional and three-dimensional problems, including examples at large deformations. Our model approaches a local model when the nonlocality parameter, the horizon size, is decreased. The proposed methodology offers a viable alternative to previous approaches in PD, which are essentially imposing mixture rules for the interfacial material parameters. © 2022 The Authors. International Journal for Numerical Methods in Engineering published by John Wiley & Sons Ltd.
Open Access
A generalized human-in-the-loop stability analysis in the presence of uncertain and redundant actuator dynamics
(American Automatic Control Council, 2022-06-08) Tohidi, Seyed Shahabaldin; Yildiz, Yildiray; Yildiz, Yildiray
This paper demonstrates the stability limits of a human-in-the-loop closed loop control system, where the plant to be controlled has redundant actuators with uncertain dynamics. The human operator is modeled as a general transfer function, unlike earlier work where specific filters are associated with human reactions. This helps with developing a more general stability analysis, and earlier studies can be considered as special cases of the proposed framework in this paper. Adaptive control allocation is employed to distribute control signals among redundant actuators. A sliding mode controller with a time-varying sliding surface provides desired control inputs to the control allocator. A flight control task, where the pilot controls the pitch angle via a pitch rate stick input is simulated to demonstrate the accuracy of the stability analysis. The Aerodata Model in Research Environment is used as the uncertain, over-actuated aircraft model.
Open Access
Capillary boosting for enhanced heat pipe performance through bifurcation of grooves: Numerical assessment and experimental validation
(2022-10) Saygan, S.; Akkus, Y.; Dursunkaya, Z.; Cetin, Barbaros; Cetin, Barbaros
In this study, an enhanced heat pipe performance for grooved heat pipes has been demonstrated through capillary boosting with the introduction of the bifurcation of grooves. Wider grooves regularly branch to narrower grooves such that the total cross-sectional liquid flow area remains approximately the same. Following the computational framework drawn by a recently developed heat pipe analysis toolbox (H-PAT), we develop a numerical model for the heat pipes with tree-like groove architecture. Then we utilize the model to design a flat-grooved heat pipe with one step groove bifurcation at the evaporator. To verify our numerical findings, two heat pipes with and without groove bifurcation are manufactured and experimented under the same conditions. Experimental results show that the numerical model can predict the thermal performance quite accurately. The results reveal that groove bifurcation can be a viable option for a better thermal performance than that of heat pipes with standard grooved heat pipes with straight grooves which leads to at least 25% higher maximum heat transport capacity. The effect of number of branching on the temperature flattening across the heat pipe is also demonstrated for different evaporator lengths.
Open Access
Investigating flank face friction during precision micro cutting of commercially pure titanium via plunging tests with diamond grooving tools
(Elsevier, 2022-01) Karpat, Yiğit; Karpat, Yiğit
This study investigates flank face friction while micro machining commercially pure titanium (cp-Ti grade 2) work material considering size effects. It is important to understand friction phenomena at the tool flank and work material surface since they affect the surface integrity of the machined parts. A single crystal diamond grooving tool is used in machining experiments to reduce the influence of cutting edge radius. In addition, plunging type of cutting experiments were performed to investigate the influence of flank face contact on the machined surface. A friction model which is based on work and tool material properties is proposed to model the contribution of adhesion and deformation of the flank face coefficient of friction. The results show that for the cp-Ti and diamond tool pair, adhesion seems to be the dominant model of friction and also contributes to the size effect. The deformation friction becomes more dominant during the chip formation stage. When cutting edge effect is eliminated, the influences of flank and rake face friction on the size effect are shown.
Open Access
A peridynamic formulation for nonlocal bone remodelling
(Taylor & Francis, 2022-04-18) Schaller, E.; Javili, Ali; Schmidt, I.; Papastavrou, A.; Steinmann, P.; Javili, Ali
Bone remodelling is a complex biomechanical process, which has been studied widely based on the restrictions of local continuum theory. To provide a nonlocal bone remodelling framework, we propose, for the first time, a peridynamic formulation on the macroscale. We illustrate our implementation with a common benchmark test as well as two load cases of the proximal femur. On the one hand, results of our peridynamic model with diminishing nonlocality measure converge to the results of a local finite element model. On the other hand, increasing the neighbourhood size shows to what extent the additional degree of freedom, the nonlocality, can influence the density evolution.