scholarly journals Shaping Soft Robotic Microactuators by Wire Electrical Discharge Grinding

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 661
Author(s):  
Edoardo Milana ◽  
Mattia Bellotti ◽  
Benjamin Gorissen ◽  
Jun Qian ◽  
Michaël De Volder ◽  
...  
Keyword(s):  
Electrical Discharge ◽  
Maximum Pressure ◽  
Cylindrical Shape ◽  
Mould Insert ◽  
Complex Deformation ◽  
Crucial Feature ◽  
Highly Sensitive ◽  
Mould Cavity ◽  
Deformation Patterns ◽  
Low Complex

Inflatable soft microactuators typically consist of an elastic material with an internal void that can be inflated to generate a deformation. A crucial feature of these actuators is the shape of ther inflatable void as it determines the bending motion. Due to fabrication limitations, low complex void geometries are the de facto standard, severely restricting attainable motions. This paper introduces wire electrical discharge grinding (WEDG) for shaping the inflatable void, increasing their complexity. This approach enables the creation of new deformation patterns and functionalities. The WEDG process is used to create various moulds to cast rubber microactuators. These microactuators are fabricated through a bonding-free micromoulding process, which is highly sensitive to the accuracy of the mould. The mould cavity (outside of the actuator) is defined by micromilling, whereas the mould insert (inner cavity of the actuator) is defined by WEDG. The deformation patterns are evaluated with a multi-segment linear bending model. The produced microactuators are also characterised and compared with respect to the morphology of the inner cavity. All microactuators have a cylindrical shape with a length of 8 mm and a diameter of 0.8 mm. Actuation tests at a maximum pressure of 50 kPa indicate that complex deformation patterns such as curling, differential bending or multi-points bending can be achieved.

Tearing Resistance of Advanced Double Hulls

1997 ◽  
Vol 41 (01) ◽  
pp. 69-80
Author(s):  
Mark D. Bracco ◽  
Tomasz Wierzbicki
Keyword(s):  
Steady State ◽  
Cutting Force ◽  
Average Error ◽  
Small Scale ◽  
Complex Deformation ◽  
Scale Models ◽  
State Force ◽  
Deformation Patterns ◽  
Double Hull ◽  
Tearing Resistance

This paper studies the cutting by a wedge of advanced double hull (ADH) small-scale models. A total of six cutting experiments were performed with six different wedge geometries. Complex deformation patterns observed in the damaged specimens were simplified to obtain a closed-form upper bound for the steady-state cutting force. The ADH steady-state cutting force solution varied from 6% above to 12% below the experimental mean steady-state force. The absolute average error is 5%.

scholarly journals Oblique collision and deformation partitioning in the SW Iberian Variscides

Solid Earth ◽  
2016 ◽  
Vol 7 (3) ◽  
pp. 857-872 ◽  
Author(s):  
Irene Pérez-Cáceres ◽  
José Fernando Simancas ◽  
David Martínez Poyatos ◽  
Antonio Azor ◽  
Francisco González Lodeiro
Keyword(s):  
Finite Strain ◽  
Lateral Displacement ◽  
Point Of View ◽  
Variscan Orogeny ◽  
Strain Partitioning ◽  
Complex Deformation ◽  
Oblique Collision ◽  
Deformation Partitioning ◽  
Oblique Convergence ◽  
Deformation Patterns

Abstract. Different transpressional scenarios have been proposed to relate kinematics and complex deformation patterns. We apply the most suitable of them to the Variscan orogeny in SW Iberia, which is characterized by a number of successive left-lateral transpressional structures developed in the Devonian to Carboniferous period. These structures resulted from the oblique convergence between three continental terranes (Central Iberian Zone, Ossa-Morena Zone and South Portuguese Zone), whose amalgamation gave way to both intense shearing at the suture-like contacts and transpressional deformation of the continental pieces in-between, thus showing strain partitioning in space and time. We have quantified the kinematics of the collisional convergence by using the available data on folding, shearing and faulting patterns, as well as tectonic fabrics and finite strain measurements. Given the uncertainties regarding the data and the boundary conditions modeled, our results must be considered as a semi-quantitative approximation to the issue, though very significant from a regional point of view. The total collisional convergence surpasses 1000 km, most of them corresponding to left-lateral displacement parallel to terrane boundaries. The average vector of convergence is oriented E–W (present-day coordinates), thus reasserting the left-lateral oblique collision in SW Iberia, in contrast with the dextral component that prevailed elsewhere in the Variscan orogen. This particular kinematics of SW Iberia is understood in the context of an Avalonian plate salient currently represented by the South Portuguese Zone.

scholarly journals Progressive Deformation Patterns from an Accretionary Prism (Helminthoid Flysch, Ligurian Alps, Italy)

Geosciences ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 26 ◽  
Author(s):  
Pierre Mueller ◽  
Matteo Maino ◽  
Silvio Seno
Keyword(s):  
Regional Scale ◽  
Kinematic Model ◽  
Outer Part ◽  
Accretionary Prism ◽  
Shear Zones ◽  
Low Grade ◽  
Progressive Deformation ◽  
Complex Deformation ◽  
Ligurian Alps ◽  
Deformation Patterns

This paper reports the results of a field-based structural investigation of a well-exposed paleo-accretionary prism, which experienced complex deformation in a low-grade metamorphic setting. Field analyses focused on the description of structural fabrics, with the main emphasis upon parameters like the orientation, style and kinematics of foliations, folds and shear zones. We address the research to the south-westernmost part of the Alpine chain, the Ligurian Alps, where, despite their origin as turbidite sequences deposited into the closing Alpine Tethys Ocean, the Helminthoid Flysch Nappes are presently distributed in the outer part of the chain, above the foreland. The new dataset highlights different deformation patterns related to the different spatial distribution of the flysch units. This regional-scale partitioning of strain is hence associated with progressive deformation within a two-stage geodynamic evolution. Correlations among the different orogenic domains allow the proposal of a kinematic model that describes the motion of the Helminthoid Flysch from the inner to the outer part of the orogen, encompassing the shift from subduction- to collision-related Alpine geodynamic phases.

scholarly journals Highly Sensitive Reentrant Cavity-Microstrip Patch Antenna Integrated Wireless Passive Pressure Sensor for High Temperature Applications

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Fei Lu ◽  
Yanjie Guo ◽  
Qiulin Tan ◽  
Tanyong Wei ◽  
Guozhu Wu ◽  
...  
Keyword(s):  
High Temperature ◽  
Pressure Sensor ◽  
Patch Antenna ◽  
Microstrip Patch Antenna ◽  
Maximum Pressure ◽  
Microstrip Patch ◽  
Passive Pressure ◽  
Highly Sensitive ◽  
Sensor Structure ◽  
Temperature Applications

A novel reentrant cavity-microstrip patch antenna integrated wireless passive pressure sensor was proposed in this paper for high temperature applications. The reentrant cavity was analyzed from aspects of distributed model and equivalent lumped circuit model, on the basis of which an optimal sensor structure integrated with a rectangular microstrip patch antenna was proposed to better transmit/receive wireless signals. In this paper, the proposed sensor was fabricated with high temperature resistant alumina ceramic and silver metalization with weld sealing, and it was measured in a hermetic metal tank with nitrogen pressure loading. It was verified that the sensor was highly sensitive, keeping stable performance up to 300 kPa with an average sensitivity of 981.8 kHz/kPa at temperature 25°C, while, for high temperature measurement, the sensor can operate properly under pressure of 60–120 kPa in the temperature range of 25–300°C with maximum pressure sensitivity of 179.2 kHz/kPa. In practical application, the proposed sensor is used in a method called table lookup with a maximum error of 5.78%.

Mould Filling and Pressure Distribution for Polymer Resins

2011 ◽  
Vol 264-265 ◽  
pp. 771-776
Author(s):  
A. Mohd ◽  
C. Hindle ◽  
W.A.Y. Yusoff
Keyword(s):  
Simulation Software ◽  
Cylindrical Shape ◽  
Moulding Process ◽  
Polymer Resin ◽  
Mould Filling ◽  
Packing Pressure ◽  
Injection Moulding Process ◽  
Mould Cavity ◽  
Mould Design ◽  
Market Needs

The application of simulation software packages for mould design and injection moulding process is becoming importance to optimizing the moulding quality and satisfy market needs. This paper presents the simulation of mould filling and packing for various polymer resin types. The filling and packing pressure phases for different type of polymer resins as well as the flow behaviour of molten resin in the mould cavity were investigated. Three common polymer resins which are amorphous and crystalline thermoplastics were used. Cylinder component cups with variation of wall thicknesses were designed. Two-cavity prototype moulds for cylindrical shape component were constructed by using AutoCAD 2006 including assembly and part drawings. The 3D model was produced by using Autodesk Inventor Professional. The result successfully revealed that polyamide resin required shorter time for filling the cavity and less pressure compared to PS and ABS.

scholarly journals Theoretical and Experimental Analysis of the Hot Torsion Process of the Hardly Deformable 5XXX Series Aluminium Alloy

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3508
Author(s):  
Konrad Błażej Laber ◽  
Beata Leszczyńska-Madej
Keyword(s):  
Mathematical Model ◽  
Stress Intensity ◽  
Aluminium Alloy ◽  
Diffraction Method ◽  
Physical Modelling ◽  
Torsion Test ◽  
Complex Deformation ◽  
Hot Torsion ◽  
Deformation Patterns

This work presents the results of the numerical and physical modelling of the hot torsion of a hardly deformable 5XXX series aluminium alloy. Studies were conducted on constrained torsion with the use of the STD 812 torsion plastometer. The main purpose of the numerical tests was to determine the influence of the accuracy of the mathematical model describing the changes in the yield stress of the tested material on the distribution of strain parameters and on the stress intensity. According to the preliminary studies, in the case of numerical modelling of the torsion test, the accuracy of the applied mathematical model describing the changes in the rheological properties of the tested material and the correct definition of the initial and boundary conditions had a particularly significant impact on the correctness of the determination of the strain parameters and the intensity of stresses. As part of the experimental tests, physical modelling of the hot torsion test was conducted. The aim of this part of the work was to determine the influence of the applied strain parameters on the distribution and size of grain as well as the microhardness of the tested aluminium alloy. Metallographic analyses were performed using light microscopy and the electron backscatter diffraction method. Due to the large inhomogeneity of the deformation parameters and the stress intensity in the torsion test, such tests were necessary for the correct determination of the so-called representative area for metallographic analyses. These types of studies are particularly important in the case of the so-called complex deformation patterns. The paper also briefly presents the results of preliminary research and future directions in which it is planned to use complex deformation patterns for physical modelling of selected processes combining various materials.

scholarly journals Progressive weakening within the overriding plate during dual inward dipping subduction

2022 ◽  
Author(s):  
ZHIBIN LEI ◽  
J. Davies
Keyword(s):  
Strain Rate ◽  
Dominant Role ◽  
Viscosity Reduction ◽  
Mantle Flow ◽  
Complex Deformation ◽  
Geodynamic Process ◽  
Multiple Parameters ◽  
Lithosphere Thinning ◽  
Subducting Plate ◽  
Deformation Patterns

Dual inward dipping subduction often produces complex deformation patterns in the overriding plate. However, the geodynamic process of how dual inward dipping subduction relates to this deformation is still poorly understood. Here we apply a composite viscosity, dependent on multiple parameters, e.g., temperature, pressure, strain rate etc., in 2-D thermo-mechanical numerical modelling to investigate how dual inward dipping subduction modifies the rheological structure of the overriding plate. Three variables are investigated to understand what controls the maximum degree of weakening. We find that the initial length and thickness of the overriding plate are negatively correlated with the magnitude of viscosity reduction. While the initial thickness of the subducting plate positively relates to the magnitude of viscosity reduction. The progressive weakening can result in a variety of stretching states ranging from 1) little or no lithosphere thinning and extension, to 2) limited thermal lithosphere thinning, and 3) localised rifting followed by spreading extension. Compared with single sided subduction, dual inward dipping subduction further reduces the magnitude of viscosity of the overriding plate. It does this by creating a dynamic fixed boundary condition for the overriding plate and forming a stronger upwelling mantle flow underlying the overriding plate. Three types of feedback weakening cycles are recognised, among which the strain rate weakening mechanism plays the dominant role in lowering the viscosity of the overriding plate throughout the simulation. Strain rate weakening is also a precondition for initiating thermal weakening, strain localisation and lithosphere thinning.

Experimental Demonstration of Failure Modes on Bellows Structures Subject to Internal Pressure

2017 ◽  
Author(s):  
Masanori Ando ◽  
Hiroki Yada ◽  
Kazuyuki Tsukimori ◽  
Masakazu Ichimiya ◽  
Yoshinari Anoda
Keyword(s):  
Internal Pressure ◽  
Evaluation Method ◽  
Failure Modes ◽  
Difficult Problem ◽  
Maximum Pressure ◽  
Test Results ◽  
Element Analysis ◽  
Complex Deformation ◽  
Explicit Analysis ◽  
Pressure Failure

In this study, in order to develop the evaluation method of the pressure toughness of bellows structures under the beyond design base event, the pressure failure tests and finite element analysis (FEA) of the bellows structures subjected to internal pressure were performed. Since the several tests and FEA results were reported previously by current authors, the additional tests were performed by the specimen simulating the real setting situation in the actual plant and for demonstrating the plain failure modes. Test specimens consist of the single and double ply bellows made of SUS304 were used. Total five specimens were tested, and one specimen was attached the guard pipe around the bellows to simulate the actual situation in the plant to confirm the effect of the neighbor structures to the ultimate toughness. The maximum pressure obtained in all tests were over 10 times larger than the estimated results of limiting design pressure based on in-plain instability by the EJMA standards; although the test specimens were pressurized exceed the pressure of buckling deformation. Because it is very difficult problem to simulate the inversion of the convolution accompanied convolutions contact for FEA with implicit method, FEA with simplified technique and explicit analysis were performed to simulating the complex deformation of the test specimen, and then these results were estimated in some procedures to compare with the test results. Three failure modes identified in the tests, however, the complex deformation behavior make it difficult to simulate by ordinary FEA procedure and to estimate the ultimate toughness of the bellows structures under the internal pressure. Therefore several kinds of idea for evaluating the ultimate toughness of the bellows structures were execute and suggested.

Glow-spark switching by a dielectric wall in a pin-to-electrolyte discharge

2015 ◽  
Vol 81 (4) ◽  
Author(s):  
Masoud Rezvani Jalal ◽  
Javad Rezvani Jalal ◽  
Saeed Fakhry ◽  
Feyzolla Younesi Zadeh ◽  
Faezeh Alvand
Keyword(s):  
Simple Model ◽  
Electrolyte Solution ◽  
Electrical Discharge ◽  
Discharge Circuit ◽  
Cylindrical Shape ◽  
Dielectric Wall ◽  
Simulation Results

In this paper, the shape, sound, and current of an electrical discharge in the air between a metal pin and an electrolyte solution are studied. Two different situations are considered: (A) without, and, (B) with inclusion of a dielectric wall in the discharge circuit. It is found that: (1) the discharge A has a cylindrical shape rather than a branched shape in discharge B, (2) the sound and current of discharge in case A are coherent and deterministic but those of case B are incoherent and stochastic. These differences along with the simulation results of a simple model demonstrate that the discharge in case A is glow, but, that in case B is spark.

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