Cohesive behaviors of hydrogel under large-scale bridging

2021 ◽  
pp. 1-25
Author(s):  
Xiaodong Wan ◽  
Yunfeng He ◽  
Yujie Chen ◽  
Canhui Yang
Keyword(s):  
Young’S Modulus ◽  
Large Scale ◽  
Young's Modulus ◽  
Vertical Displacement ◽  
Bending Stiffness ◽  
Scale Bridging ◽  
Extended Length ◽  
Minimum Potential ◽  
Peel Force ◽  
Force Displacement

Abstract It has been recently revealed that large-scale bridging mechanism can be invoked to drastically improve the debonding resistance of hydrogel adhesion, but the optimization of the improvement remains elusive. Aiming at shedding light on the optimization, the present paper investigates the cohesive behaviors of hydrogel under the condition of large-scale bridging in 90-degree peel. A quasi-static model is established based on the principle of minimum potential energy, with the traction-separation law determined from experiments. The model is proved reliable in predicting the force-displacement response and the backing profile up to the peak peel force. Further theoretical analyses indicate that, within the range of interest, the peak peel force decreases with the extended length, increases with the Young's modulus of backing, increases then plateaus with the adhesion length and the thickness and bending stiffness of backing. In addition, the vertical displacement at peak peel force escalates with the extended length, remains mostly constant with varying adhesion length, declines with the Young's modulus of backing, and declines then stabilizes with increasing thickness and bending stiffness of backing. These theoretical insights may help tailor the material properties and geometric parameters for on-demand design of hydrogel adhesion as well as other soft adhesives for biomedicine and engineering.

scholarly journals Young’s Modulus of Polycrystalline Titania Microspheres Determined by In Situ Nanoindentation and Finite Element Modeling

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Peida Hao ◽  
Yanping Liu ◽  
Yuanming Du ◽  
Yuefei Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Deformation Mechanisms ◽  
Displacement Curve ◽  
Element Simulation ◽  
Nanoindentation Experiment ◽  
Force Displacement

In situ nanoindentation was employed to probe the mechanical properties of individual polycrystalline titania (TiO2) microspheres. The force-displacement curves captured by a hybrid scanning electron microscope/scanning probe microscope (SEM/SPM) system were analyzed based on Hertz’s theory of contact mechanics. However, the deformation mechanisms of the nano/microspheres in the nanoindentation tests are not very clear. Finite element simulation was employed to investigate the deformation of spheres at the nanoscale under the pressure of an AFM tip. Then a revised method for the calculation of Young’s modulus of the microspheres was presented based on the deformation mechanisms of the spheres and Hertz’s theory. Meanwhile, a new force-displacement curve was reproduced by finite element simulation with the new calculation, and it was compared with the curve obtained by the nanoindentation experiment. The results of the comparison show that utilization of this revised model produces more accurate results. The calculated results showed that Young’s modulus of a polycrystalline TiO2microsphere was approximately 30% larger than that of the bulk counterpart.

scholarly journals Approximate Dynamic Programming Based Control of Proppant Concentration in Hydraulic Fracturing

Mathematics ◽  
2018 ◽  
Vol 6 (8) ◽  
pp. 132 ◽  
Author(s):  
Harwinder Singh Sidhu ◽  
Prashanth Siddhamshetty ◽  
Joseph Kwon
Keyword(s):  
Mechanical Properties ◽  
Dynamic Programming ◽  
Hydraulic Fracturing ◽  
Young’S Modulus ◽  
Large Scale ◽  
Approximate Dynamic Programming ◽  
Young's Modulus ◽  
Computational Cost ◽  
Control Technique ◽  
Rock Mechanical Properties

Hydraulic fracturing has played a crucial role in enhancing the extraction of oil and gas from deep underground sources. The two main objectives of hydraulic fracturing are to produce fractures with a desired fracture geometry and to achieve the target proppant concentration inside the fracture. Recently, some efforts have been made to accomplish these objectives by the model predictive control (MPC) theory based on the assumption that the rock mechanical properties such as the Young’s modulus are known and spatially homogenous. However, this approach may not be optimal if there is an uncertainty in the rock mechanical properties. Furthermore, the computational requirements associated with the MPC approach to calculate the control moves at each sampling time can be significantly high when the underlying process dynamics is described by a nonlinear large-scale system. To address these issues, the current work proposes an approximate dynamic programming (ADP) based approach for the closed-loop control of hydraulic fracturing to achieve the target proppant concentration at the end of pumping. ADP is a model-based control technique which combines a high-fidelity simulation and function approximator to alleviate the “curse-of-dimensionality” associated with the traditional dynamic programming (DP) approach. A series of simulations results is provided to demonstrate the performance of the ADP-based controller in achieving the target proppant concentration at the end of pumping at a fraction of the computational cost required by MPC while handling the uncertainty in the Young’s modulus of the rock formation.

scholarly journals Dynamic Radiation Effects Induced by Short-Pulsed GeV U-Ion Beams in Graphite and h-BN Targets

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Philipp Bolz ◽  
Philipp Drechsel ◽  
Alexey Prosvetov ◽  
Pascal Simon ◽  
Christina Trautmann ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Young’S Modulus ◽  
Radiation Effects ◽  
Large Scale ◽  
Hexagonal Boron Nitride ◽  
Young's Modulus ◽  
Target Surface ◽  
High Dose ◽  
Velocity Signal ◽  
Isotropic Graphite

Targets of isotropic graphite and hexagonal boron nitride were exposed to short pulses of uranium ions with ∼1 GeV kinetic energy. The deposited power density of ∼3 MW/cm³ generates thermal stress in the samples leading to pressure waves. The velocity of the respective motion of the target surface was measured by laser Doppler vibrometry. The bending modes are identified as the dominant components in the velocity signal recorded as a function of time. With accumulated radiation damage, the bending mode frequency shifts towards higher values. Based on this shift, Young’s modulus of irradiated isotropic graphite is determined by comparison with ANSYS simulations. The increase of Young’s modulus up to 3 times the pristine value for the highest accumulated fluence of 3 × 1013 ions/cm2 is attributed to the beam-induced microstructural evolution into a disordered structure similar to glassy carbon. Young’s modulus values deduced from microindentation measurements are similar, confirming the validity of the method. Beam-induced stress waves remain in the elastic regime, and no large-scale damage can be observed in graphite. Hexagonal boron nitride shows lower radiation resistance. Circular cracks are generated already at low fluences, risking material failure when applied in high-dose environment.

scholarly journals Integrated dynamic wet spinning of core-sheath hydrogel fibers for optical-to-brain/tissue communications

2020 ◽  
Author(s):  
Guoyin Chen ◽  
Gang Wang ◽  
Xinrong Tan ◽  
Kai Hou ◽  
Qingshuo Meng ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Optical Fibers ◽  
Rational Design ◽  
Large Scale ◽  
Young's Modulus ◽  
Solution Viscosity ◽  
Wet Spinning ◽  
Deep Tissue ◽  
Optogenetic Stimulation ◽  
Tissue Therapy

Abstract Hydrogel optical light-guides have received substantial interest for applications such as deep-tissue biosensors, optogenetic stimulation and photomedicine due to their biocompatibility, (micro)structure control and tissue-like Young's modulus. However, despite recent developments, large-scale fabrication with a continuous synthetic methodology, which could produce core-sheath hydrogel fibers with the desired optical and mechanical properties suitable for deep-tissue applications, has yet to be achieved. In this study, we report a versatile concept of integrated light-triggered dynamic wet spinning capable of continuously producing core-sheath hydrogel optical fibers with tunable fiber diameters, and mechanical and optical propagation properties. Furthermore, this concept also exhibited versatility for various kinds of core-sheath functional fibers. The wet spinning synthetic procedure and fabrication process were optimized with the rational design of the core/sheath material interface compatibility [core = poly(ethylene glycol diacrylate-co-acrylamide); sheath = Ca-alginate], optical transparency, refractive index and spinning solution viscosity. The resulting hydrogel optical fibers exhibited desirable low optical attenuation (0.18 ± 0.01 dB cm−1 with 650 nm laser light), excellent biocompatibility and tissue-like Young's modulus (<2.60 MPa). The optical waveguide hydrogel fibers were successfully employed for deep-tissue cancer therapy and brain optogenetic stimulation, confirming that they could serve as an efficient versatile tool for diverse deep-tissue therapy and brain optogenetic applications.

Advanced Optimization of Industrial Large-Scale Roll-to-Roll Systems Under Parametric Uncertainties

2012 ◽  
Author(s):  
J. Frechard ◽  
D. Knittel
Keyword(s):  
Young’S Modulus ◽  
Large Scale ◽  
Young's Modulus ◽  
Robust Design Optimization ◽  
Parametric Uncertainties ◽  
Optimization Approach ◽  
Roll To Roll ◽  
Polymer Metal ◽  
The Web ◽  
Web Tension

In industrial plants some parameters can not be evaluated properly or they are varying with time. These parametric uncertainties has to be taken into account during the design process of industrial systems. In this work, the developped optimization approach is applied on an industrial roll-to-roll sytem. Such systems are commonly used to handle materials as polymer, metal, paper and textile. The key challenge is to move the web at the expected speed while maintaining the web tension in an acceptable range around its reference. Moreover, the Young’s modulus of the web is difficult to evaluate and it is varying with time due to temperature and moisture variations. This paper deals with the web tension controller synthesis on a large-scale roll-to-roll system with uncertain Young’s modulus. To synthesize web tension controllers, an H∞ approach is applied and adapted to the system with parametric uncertainties using multi-objective robust design optimization.

Development of Porous Material with High Young’s Modulus and Low Thermal Expansion Coefficient in SiC-Vitrified Bonding Material-LiAlSiO4 System

2009 ◽  
Vol 620-622 ◽  
pp. 715-718 ◽  
Author(s):  
Tatsuya Ono ◽  
Koji Matsumaru ◽  
Isaías Juárez-Ramírez ◽  
Leticia M. Torres-Martínez ◽  
Kozo Ishizaki
Keyword(s):  
Thermal Expansion ◽  
Porous Material ◽  
Porous Materials ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Large Scale ◽  
Young's Modulus ◽  
Negative Thermal Expansion ◽  
Low Thermal Expansion

Machines for manufacturing large scale flat displays are enlarging as the size of glasses increases. This work develops porous materials with a low thermal expansion coefficient and a high Young’s modulus. SiC and LiAlSiO4 were used for a positive and a negative thermal expansion materials, respectively. Compositions of powders for porous materials were determined to obtain a desirable Young’s modulus and thermal expansion coefficient by using SiC-VBM-LiAlSiO4 phase diagram at 20 % of porosity. The empirical values of Young’s modulus and a thermal expansion coefficient are close to the theoretical values by using the diagram. Fabricated porous material had high enough Young’s modulus of 87 GPa, and low enough thermal expansion coefficient of 2 x 10-6 K-1 at temperatures ranging from -17 °C to 190 °C with 22 % of porosity.

Investigation into the Dynamic Fracture Properties of Large Scale Functionally Graded Materials

2006 ◽  
Vol 324-325 ◽  
pp. 239-242 ◽  
Author(s):  
Xiao Bin Yang ◽  
Zhuo Zhuang ◽  
Xue Feng Yao
Keyword(s):  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Large Scale ◽  
Young's Modulus ◽  
Mass Density ◽  
Poisson's Ratio ◽  
Constant Mass ◽  
Functionally Gradient Materials ◽  
Gradient Materials ◽  
Functionally Gradient

A crack propagation perpendicular to gradient in a large scale functionally gradient materials, which has (1) a linear variation of Young’s modulus with a constant mass density and Poisson’s ratio, and (2) a exponential variation of Young’s modulus with a constant mass density and Poisson’s ratio, is modelled by finite element methods. Based on the experimental result of large scale functionally gradient materials, the dynamic propagation process of the FGMs is modelled and the dynamic parameters, like the energy release rate and crack tip opening angle, are calculated through a generation phase.

scholarly journals An Innovative Own-Weight Cantilever Method for Measuring Young’s Modulus in Flexible Thin Materials Based on Large Deflections

2010 ◽  
Vol 24-25 ◽  
pp. 371-377 ◽  
Author(s):  
Atsumi Ohtsuki
Keyword(s):  
Large Deformation ◽  
Young’S Modulus ◽  
Deformation Theory ◽  
Bessel Functions ◽  
Young's Modulus ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Thin Wires ◽  
Deformation Behaviors ◽  
Piano Wire

This report deals with an innovative method (Own-Weight Cantilever Method) to measure Young’s modulus of flexible thin materials. A newly developed method is based on the large deformation theory considering large deformation behaviors due to own-weight in flexible thin materials. Analytical solutions are derived by using Bessel Functions. By means of measuring the horizontal displacement or the vertical displacement at a free end of a cantilever, Young’s modulus can be easily obtained for various flexible thin and long materials. Measurements were carried out on a piano wire. The results confirm that the new method is suitable for flexible thin wires.

Polysilicon Tensile Testing With Electrostatic Gripping

1998 ◽  
Vol 518 ◽  
Author(s):  
W. N. Sharpe ◽  
K. Turner ◽  
R. L. Edwards
Keyword(s):  
North Carolina ◽  
Young’S Modulus ◽  
Tensile Testing ◽  
Young's Modulus ◽  
Strain Curve ◽  
Electrostatic Forces ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Force Displacement

AbstractTechniques and procedures are described for tensile testing of polysilicon specimens that are 1.5 or 3.5 νm thick and have various widths and lengths. The specimens are fixed to the wafer at one end and have a large free end that can be gripped by electrostatic forces. This enables easy handling and testing and permits the deposition of 18 specimens on a one-centimeter square portion of a wafer. The displacement of the free end is monitored, which allows one to extract Young's modulus from the force-displacement record. Some of the wider specimens have two gold lines applied so that strain can be measured interferometrically directly on the specimen to record a stress-strain curve.The specimens were produced at the Microelectronics Center of North Carolina (MCNC). When compared with earlier results of wider MCNC specimens that were 3.5 μm thick, the Young's modulus is smaller and the strength is slightly larger.

scholarly journals An Innovative Circular Ring Method for Measuring Young’s Modulus of Thin Flexible Multi-Layered Materials

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 553
Author(s):  
Atsumi Ohtsuki
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
Layered Materials ◽  
Circular Ring ◽  
Thin Layers ◽  
New Method ◽  
Thin Wires ◽  
Ring Method

An innovative mechanical testing method (Compressive Circular Ring Method) is provided for measuring Young’s modulus of each layer in a flexible multi-layered material. The method is based on a nonlinear large deformation theory. By just measuring the vertical displacement or the horizontal displacement of the ring, Young’s modulus of each layer can be easily obtained for various thin multi-layered materials. Measurements were carried out on an electrodeposited twolayered wire. The results confirm that the new method is suitable for flexible multi-layered thin wires. In the meantime, the new method can be applied widely to measure Young’s modulus of thin layers formed by PVD, CVD, Coating, Paint, Cladding, Lamination, and others.

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