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Full-Text Articles in Social and Behavioral Sciences
A 3d Printed Modular Soft Gripper For Conformal Grasping, Charbel Tawk, Rahim Mutlu, Gursel Alici
A 3d Printed Modular Soft Gripper For Conformal Grasping, Charbel Tawk, Rahim Mutlu, Gursel Alici
Faculty of Engineering and Information Sciences - Papers: Part A
© 2020 IEEE. In this work, a 3D printed modular soft gripper with highly conformal soft fingers was developed. A soft auxetic structure with compliant ribs is 3D printed simultaneously with each soft pneumatic finger for conformal grasping. The fingers of the soft gripper were printed monolithically, without requiring support material and postprocessing, using a low-cost and open-source fused deposition modeling (FDM) 3D printer that employs a commercially available thermoplastic polyurethane (TPU). The soft fingers of the gripper were optimized using finite element modeling (FEM). The FE simulations accurately predicted the performance of the fingers in terms of deformation and …
Influence Of Particle Gradation And Shape On The Performance Of Stone Columns In Soft Clay, Firman Siahaan, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn, Ana Heitor
Influence Of Particle Gradation And Shape On The Performance Of Stone Columns In Soft Clay, Firman Siahaan, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn, Ana Heitor
Faculty of Engineering and Information Sciences - Papers: Part B
A stone column typically consists of particles whose influence has largely been overlooked in design practice in terms of stress transfer, pattern of deformation, and intrusion of fines (clogging). This article presents an experimental study on the load-deformation behavior of a model stone column installed in soft clay with a particular emphasis on the influence of particle gradation and shape under undrained loading. The results show that particle gradation and shape have a significant influence on the load-deformation behavior and the extent of fines intrusion into the stone columns. Relatively well-graded particle sizes favor the development of higher peak shear …
A 3d Printed Monolithic Soft Gripper With Adjustable Stiffness, Rahim Mutlu, Charbel Tawk, Gursel Alici, Emre Sariyildiz
A 3d Printed Monolithic Soft Gripper With Adjustable Stiffness, Rahim Mutlu, Charbel Tawk, Gursel Alici, Emre Sariyildiz
Faculty of Engineering and Information Sciences - Papers: Part B
Soft robotics has recently gained a significant momentum as a newly emerging field in robotics that focuses on biomimicry, compliancy and conformability with safety in near-human environments. Beside conventional fabrication methods, additive manufacturing is a primary technique to employ to fabricate soft robotic devices. We developed a monolithic soft gripper, with variable stiffness fingers, that was fabricated as a one-piece device. Negative pressure was used for the actuation of the gripper while positive pressure was used to vary the stiffness of the fingers of the gripper. Finger bending and gripping capabilities of the monolithic soft gripper were experimentally tested. Finite …
Soft Soil Stabilisation Through Native Vegetation Along Rail Corridors, Udeshini Pathirage, Buddhima Indraratna, Ana Heitor
Soft Soil Stabilisation Through Native Vegetation Along Rail Corridors, Udeshini Pathirage, Buddhima Indraratna, Ana Heitor
Faculty of Engineering and Information Sciences - Papers: Part A
The 'green corridor' concept along the railway lines is an emerging research area in bio-engineering as form of subgrade soil stabilization. Native trees grown along rail corridors increase the matric suction of the subgrade through the root water uptake associated with the evapo-transpiration by the tree canopy. One of the most important aspects in subsoil improvement through native vegetation is the effect of osmotic suction attributed to solute uptake by active root hairs. The current study offers to capture the effect of matric and osmotic suction to overcome the existing empirical relations which are applicable mainly for site-specific controlled conditions. …
Coupled Discrete Element-Finite Difference Method For Analysing The Load-Deformation Behaviour Of A Single Stone Column In Soft Soil, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn, Scott W. Sloan
Coupled Discrete Element-Finite Difference Method For Analysing The Load-Deformation Behaviour Of A Single Stone Column In Soft Soil, Buddhima Indraratna, Ngoc Trung Ngo, Cholachat Rujikiatkamjorn, Scott W. Sloan
Faculty of Engineering and Information Sciences - Papers: Part A
Experimental studies and numerical modelling of the deformation of soft clay stabilised by stone columns have been conducted over the past few decades. Continuum-based numerical models have provided valuable insight into the prediction of settlement, lateral deformation, and stress and strain-rate dependent behaviour of stone columns at a macroscopic scale, but because they consist of granular material such as crushed rock, gravel, and waste rock aggregates, their behaviour is influenced by inter-particle micromechanics and cannot be modelled properly using these models. In this paper a novel coupled model of the discrete element method (DEM) and finite difference method (FDM) is …
Towards Soft Robotic Devices For Site-Specific Drug Delivery, Gursel Alici
Towards Soft Robotic Devices For Site-Specific Drug Delivery, Gursel Alici
Faculty of Engineering and Information Sciences - Papers: Part A
Considerable research efforts have recently been dedicated to the establishment of various drug delivery systems (DDS) that are mechanical/physical, chemical and biological/molecular DDS. In this paper, we report on the recent advances in site-specific drug delivery (site-specific, controlled, targeted or smart drug delivery are terms used interchangeably in the literature, to mean to transport a drug or a therapeutic agent to a desired location within the body and release it as desired with negligibly small toxicity and side effect compared to classical drug administration means such as peroral, parenteral, transmucosal, topical and inhalation) based on mechanical/physical systems consisting of implantable …
Soft, Flexible Micromanipulators Comprising Polypyrrole Trilayer Microactuators, Alexandre Khaldi, Ali Maziz, Gursel Alici, Geoffrey M. Spinks, Edwin W. Jager
Soft, Flexible Micromanipulators Comprising Polypyrrole Trilayer Microactuators, Alexandre Khaldi, Ali Maziz, Gursel Alici, Geoffrey M. Spinks, Edwin W. Jager
Faculty of Engineering and Information Sciences - Papers: Part A
Within the areas of cell biology, biomedicine and minimal invasive surgery, there is a need for soft, flexible and dextrous biocompatible manipulators for handling biological objects, such as single cells and tissues. Present day technologies are based on simple suction using micropipettes for grasping objects. The micropipettes lack the possibility of accurate force control, nor are they soft and compliant and may thus cause damage to the cells or tissue. Other micromanipulators use conventional electric motors however the further miniaturization of electrical motors and their associated gear boxes and/or push/pull wires has reached its limits. Therefore there is an urgent …
Modeling A Soft Robotic Mechanism Articulated With Dielectric Elastomer Actuators, Chuc H. Nguyen, Gursel Alici, Rahim Mutlu
Modeling A Soft Robotic Mechanism Articulated With Dielectric Elastomer Actuators, Chuc H. Nguyen, Gursel Alici, Rahim Mutlu
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, a translational actuation mechanism in the form of a parallel-crank mechanism (i.e. double-crank 4-bar mechanism) articulated with two dielectric elastomer actuators working in parallel are fabricated. This structure, which is a fully soft mechanism, is established by stretching a dielectric elastomer (DE) film over a PET (polyethylene terephthalate) frame so that the energy released from the stretched DE film is stored in the frame as bending energy. The mechanism generates a translational output under a driving voltage applied between two electrodes of the DE film. The visco-elastic models are proposed for the mechanism so that the mechanical …
A Deformation Mechanism Of Hard Metal Surrounded By Soft Metal During Roll Forming, Hailiang Yu, A Kiet Tieu, Cheng Lu, Xiong Liu, Ajit Godbole, Huijun Li, Charlie Kong, Q Qin
A Deformation Mechanism Of Hard Metal Surrounded By Soft Metal During Roll Forming, Hailiang Yu, A Kiet Tieu, Cheng Lu, Xiong Liu, Ajit Godbole, Huijun Li, Charlie Kong, Q Qin
Faculty of Engineering and Information Sciences - Papers: Part A
It is interesting to imagine what would happen when a mixture of soft-boiled eggs and stones is deformed together. A foil made of pure Ti is stronger than that made of Cu. When a composite Cu/Ti foil deforms, the harder Ti will penetrate into the softer Cu in the convex shapes according to previously reported results. In this paper, we describe the fabrication of multilayer Cu/Ti foils by the roll bonding technique and report our observations. The experimental results lead us to propose a new deformation mechanism for a hard metal surrounded by a soft metal during rolling of a …
Environmental Sustainability Of Soft Soil Improvement Via Vacuum And Surcharge Preloading, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Environmental Sustainability Of Soft Soil Improvement Via Vacuum And Surcharge Preloading, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Faculty of Engineering and Information Sciences - Papers: Part A
Due to environmental concerns, sustainable ground improvement is considered a critical part of modern infrastructure development. Current policy on environmental sustainability often expects noise-free, chemical-free, and low carbon emission processes, while being economical. In this context, the application of prefabricated vertical drains (PVD) with vacuum preloading is regarded as one of the most sustainable ground improvement techniques. Compared with other ground improvement methods such as piling and chemical stabilization, this method will not only save a considerable cost in embankment construction, but will also improve the construction rate of coastal highways and rail tracks and their load-carrying capacity. The utilization …
Numerical Solution Of Stone Column Improved Soft Soil Considering Arching, Clogging And Smear Effects, Buddhima Indraratna, Sudip Basack, Cholachat Rujikiatkamjorn
Numerical Solution Of Stone Column Improved Soft Soil Considering Arching, Clogging And Smear Effects, Buddhima Indraratna, Sudip Basack, Cholachat Rujikiatkamjorn
Faculty of Engineering and Information Sciences - Papers: Part A
Improvement of soft clay deposits by the installation of stone columns is one of the most popular techniques followed worldwide. The stone columns not only act as reinforcingmaterial increasing the overall strength and stiffness of the compressible soft soil, but they also promote consolidation through effective drainage. The analytical and numerical solutions available for ascertaining the response of column-reinforced soil have been developed on the basis of the equal strain hypothesis. For typical surcharge (embankment) loading, the free strain analysis appears to give more realistic results comparable to field data. The paper presents a novel numericalmodel (finite-differencemethod) to analyze the …
Current State Of The Art In Vacuum Preloading For Stabilising Soft Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Current State Of The Art In Vacuum Preloading For Stabilising Soft Soil, Cholachat Rujikiatkamjorn, Buddhima Indraratna
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper the analytical solutions for radial consolidation that include time dependent surcharge loading and vacuum pressure are proposed, whilst also considering the impact of the parabolic variation of permeability in the smear zone. The use of the spectral method for multilayered soil consolidation is introduced and verified. The Elliptical Cavity Expansion Theory is used to predict the extent of soil disturbance (smear zone) caused by the installation of mandrel driven vertical drains. The predicted smear zone is then compared to the data obtained from large-scale radial consolidation tests. Furthermore, the advantages and limitations of applying a vacuum through …
Analyses Of Reinforced Embankment On Soft And Hard Foundations, Sowarapan Duangkhae, Dennes Bergado, Pankaj Baral, Barry T. Ocay
Analyses Of Reinforced Embankment On Soft And Hard Foundations, Sowarapan Duangkhae, Dennes Bergado, Pankaj Baral, Barry T. Ocay
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper, the analyses and design using conservative limit equilibrium methods (AASHTO simplified and FHWA structure stiffness methods) were compared with the working stress methods called K-stiffness method (original and modified K-stiffness methods). Moreover, the predictions from the K-stiffness methods were confirmed from the observed data for a reinforced embankment on a hard foundation. Furthermore, since the reinforcement loads increased due to post-construction settlements for reinforced embankments on soft foundation, a further modification of the K-stiffness method is proposed. This further modification is concerned with the proposed settlement factor. The validity of this further modification is demonstrated by the …
An Effective Methodology To Solve Inverse Kinematics Of Electroactive Polymer Actuators Modelled As Active And Soft Robotic Structures, Rahim Mutlu, Gursel Alici, Weihua Li
An Effective Methodology To Solve Inverse Kinematics Of Electroactive Polymer Actuators Modelled As Active And Soft Robotic Structures, Rahim Mutlu, Gursel Alici, Weihua Li
Faculty of Engineering and Information Sciences - Papers: Part A
Electroactive polymers (EAPs) generate highly non-linear deflections when they are used as actuators, which are known as artificial muscles. Though several modelling methods have been proposed before to understand their mechanical, chemical, electrical behaviours or 'electro-chemo-mechanical' behaviour, estimating the whole shape deflection of the EAP actuators has not been studied yet. Therefore, we report on (i) an effective methodology to estimate these actuators' whole shape deflection by employing a soft robotic actuator/manipulator approach and (ii) an angle optimization method, which we call AngleOPT, to accurately solve the EAP actuators' inverse kinematic problem. Laminated polypyrrole (PPy) EAP actuators are employed to …
Electroactive Polymers As Soft Robotic Actuators: Electromechanical Modeling And Identification, Rahim Mutlu, Gursel Alici, Weihua Li
Electroactive Polymers As Soft Robotic Actuators: Electromechanical Modeling And Identification, Rahim Mutlu, Gursel Alici, Weihua Li
Faculty of Engineering and Information Sciences - Papers: Part A
Biologically inspired robotic applications have recently received significant attention due to developments in novel materials and actuators with an operation principle similar to the natural muscles’. Electroactive polymer (EAP) actuators, also known as artificial muscles, possess extraordinary properties such as low efficiency consumption, compliance, bio-compatibility and ability to be miniaturized. Although several methodologies have been proposed for modeling and identification of their quasi-static bending behavior, a negligibly small attention has been given to their dynamic behavior. In this paper, we, therefore, report on their electromechanical modeling and parameter identification. We model the tri-layer EAP actuators as a soft robotic actuator …
A Low Cost Soft Mapper For Turbo Equalization With High Order Modulation, Licai Fang, Qinghua Guo, Defeng (David) Huang, Sven Nordholm
A Low Cost Soft Mapper For Turbo Equalization With High Order Modulation, Licai Fang, Qinghua Guo, Defeng (David) Huang, Sven Nordholm
Faculty of Engineering and Information Sciences - Papers: Part A
In an MMSE based turbo equalization system, a soft mapper calculates the symbol mean and variance based on extrinsic Log-Likelihood-Ratios (LLRs) information coming from a Soft-Input Soft-Output (SISO) decoder. In this paper, we investigate the complexity of this module, and in particular, we employ a 3-segment linear approximation approach to calculate the mean and variance of data symbols from LLRs. For FPGA and VLSI implementation, we propose novel piecewise linear functions which map LLR to the mean and variance directly without the use of any two-variable-input multipliers. Simulation results for 16-QAM and 64-QAM show that the no multiplier approach has …
Finite Element Analysis Of Consolidation Behavior Of Composite Soft Ground, S Horpibulsuk, A Chinkulkijniwat, A Cholaphatsron, J Suebsuk, M D. Liu
Finite Element Analysis Of Consolidation Behavior Of Composite Soft Ground, S Horpibulsuk, A Chinkulkijniwat, A Cholaphatsron, J Suebsuk, M D. Liu
Faculty of Engineering and Information Sciences - Papers: Part A
Columnar inclusion is one of the effective and widely used methods for improving engineering properties of soft clay ground. This paper investigates the consolidation behavior of composite soft clay ground using both physical model tests under an axial-symmetry condition and finite element simulations using the PLAXIS 2D program. Because the soil-cement column enhances the yield stress and stiffness of the composite ground, the composite ground is in an over-consolidated state under the applied vertical applied stresses. At this state, the rate of consolidation is rapid due to a high coefficient of consolidation. The consolidation of the composite ground is mainly …
A Soft-In Soft-Out Detection Approach Using Partial Gaussian Approximation, Qinghua Guo, Licai Fang, Defeng (David) Huang, Sven Nordholm
A Soft-In Soft-Out Detection Approach Using Partial Gaussian Approximation, Qinghua Guo, Licai Fang, Defeng (David) Huang, Sven Nordholm
Faculty of Engineering and Information Sciences - Papers: Part A
This paper concerns the implementation of the softin soft-out detector in an iterative detection system. A detection approach is proposed based on the properties of Gaussian functions. In this approach, for the computation of the APP (a posteriori probability) of a concerned symbol, the other symbols are distinguished based on their contributions to the APP of the concerned symbol, and the symbols with less contributions are treated as Gaussian variables to reduce the computational complexity. The exact APP detector and the well-known LMMSE (linear minimum mean square error) detector are two special cases of the proposed detector. Simulation results show …
Three-Dimensional Nonlinear Analysis Of Seismic Ground Response Of Soft Soils In Shanghai, Qingsheng Chen, Guangyun Gao, Junfeng He
Three-Dimensional Nonlinear Analysis Of Seismic Ground Response Of Soft Soils In Shanghai, Qingsheng Chen, Guangyun Gao, Junfeng He
Faculty of Engineering and Information Sciences - Papers: Part A
Reduced order bounding surface model was employed to study 3-D seismic ground response of site considering the nonlinearity of soft soils in Shanghai. A nonlinear procedure for response analysis of horizontal layered sites subjected to multidirectional earthquake loading was used to study vertical and horizontal ground responses, respectively, under unidirectional and multidirectional base excitations (Taft). Also, the development of ratio of vertical and horizontal peak acceleration and the effects of the variation of groundwater table on the characteristics of seismic responses were studied. The study results show that the characteristics of vertical seismic ground response are much different from those …
Iterative Soft Compensation For Ofdm Systems With Clipping And Superposition Coded Modulation, Jun Tong, Li Ping, Zhonghao Zhang, Vijay Bhargava
Iterative Soft Compensation For Ofdm Systems With Clipping And Superposition Coded Modulation, Jun Tong, Li Ping, Zhonghao Zhang, Vijay Bhargava
Faculty of Engineering and Information Sciences - Papers: Part A
This paper deals with the clipping method used in orthogonal frequency-division multiplexing (OFDM) systems to reduce the peak-to-average power ratio (PAPR). An iterative soft compensation method is proposed to mitigate the clipping distortion, which can outperform conventional treatments. The impact of signaling schemes on the residual clipping noise power is studied via the symbol variance analysis. It is found that superposition coded modulation (SCM) can minimize the residual clipping noise power among all possible signaling schemes. This indicates that SCM-based OFDM systems are more robust to clipping effect than other alternatives when soft compensation is applied. It is also shown …
The Soft X-Ray Background: Evidence For Widespread Disruption Of The Gas Haloes Of Galaxy Groups, K K S Wu, A C. Fabian, Paul E. J Nulsen
The Soft X-Ray Background: Evidence For Widespread Disruption Of The Gas Haloes Of Galaxy Groups, K K S Wu, A C. Fabian, Paul E. J Nulsen
Faculty of Engineering and Information Sciences - Papers: Part A
Almost all of the extragalactic X-ray background (XRB) at 0.25 keV can be accounted for by radio-quiet quasars, allowing us to derive an upper limit of 4 keV cm−2 s−1 sr−1 keV−1 for the remaining background at 0.25 keV. However, the XRB from the gas haloes of groups of galaxies, with gas removal resulting from cooling accounted for, exceeds this upper limit by an order of magnitude if non-gravitational heating is not included. We calculate this using simulations of halo merger trees and realistic gas density profiles, which we require to reproduce the observed gas fractions …
On The Soft X-Ray Spectrum Of Cooling Flows, A C. Fabian, R F. Mushotzky, Paul E. J Nulsen, J R. Peterson
On The Soft X-Ray Spectrum Of Cooling Flows, A C. Fabian, R F. Mushotzky, Paul E. J Nulsen, J R. Peterson
Faculty of Engineering and Information Sciences - Papers: Part A
Strong evidence for cooling flows has been found in low-resolution X-ray imaging and spectra of many clusters of galaxies. However, high-resolution X-ray spectra of several clusters from the Reflection Grating Spectrometer on XMM-Newton now show a soft X-ray spectrum inconsistent with a simple cooling flow. The main problem is a lack of the emission lines expected from gas cooling below 1–2 keV. Lines from gas at about 2–3 keV are observed, even in a high-temperature cluster such as A1835, indicating that gas is cooling down to about 2–3 keV, but is not found at lower temperatures. Here we discuss several …