The Graded Origami Structures

2015 ◽  
Author(s):  
Ruikang Xie ◽  
Jianmin Li ◽  
Yan Chen
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Engineering Application ◽  
Geometric Parameters ◽  
Sandwich Beams ◽  
Three Point Bending ◽  
Graded Structure ◽  
Sector Angle ◽  
Graded Structures ◽  
Bending Response

There are many excellent graded structures existing in nature to optimize the mechanical properties in various load situations by adjusting the distribution of materials. In this research, rigid origami and graded structure concept are combined together to form the graded origami structures. Seven methods are proposed, including changing the length of crease lines, changing the sector angle, changing the number of units, and the combinations of them. Two rigid origami patterns, Miura-ori and Arc-Miura, are chosen to generate the graded origami structures, and the geometric parameters of each pattern are studied. For engineering application, quasi-static three-point bending response of sandwich beams with graded Miura-ori core based on changing the number of units and changing both the length of crease lines and the sector angle is explored. The investigation reveals that sandwich beams with graded Miura-ori core have preferable energy absorption capability in this load situation compared with the normal Miura-ori core.

scholarly journals Forming Complex Graded and Homogeneous Components by Joining Simple Presintered Parts of TRIP-Matrix Composite through Powder Forging

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 543 ◽  
Author(s):  
Markus Kirschner ◽  
Stefan Martin ◽  
Sergey Guk ◽  
Ulrich Prahl ◽  
Rudolf Kawalla
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Steel Matrix ◽  
Forming Process ◽  
Form Complex ◽  
Transformation Induced Plasticity ◽  
Graded Structure ◽  
Material Systems ◽  
Significant Step ◽  
Graded Structures

The ability to fabricate complex graded structures would be a significant step towards the manufacturing of material systems with properties tailored to individual applications. While powder metallurgy has had some success in this regard, it requires that the semi-finished products be exactly similar to the final component. However, it is significantly cheaper to produce simple, semi-finished products and then join them to form complex components with the desired graded structure through powder forging and simultaneous compaction. It is also essential that the graded structure of the semi-finished products is retained during the forming process. In this study, pre-sintered cylindrical semi-finished products consisting of identical homogeneous layers as well as graded components consisting of non-identical homogeneous layers were joined using powder forging at 1100 °C. The microstructures and densities as well as the mechanical properties of the final components were investigated. It was observed that, upon compaction, the components formed solid structures, in which the reinforcing ZrO2 particles were completely integrated within the transformation-induced plasticity steel matrix. Finally, it was confirmed that the graded structure of the semi-finished products was retained in the final components.

Mechanical Response of Composite Sandwich Panels: Deformation and Energy Absorption

2013 ◽  
Vol 535-536 ◽  
pp. 409-412 ◽  
Author(s):  
Martin Vcelka ◽  
Yvonne Durandet ◽  
Christopher C. Berndt ◽  
Dong Ruan
Keyword(s):  
Energy Absorption ◽  
Mechanical Response ◽  
Strain Rates ◽  
Sandwich Beams ◽  
Specific Energy Absorption ◽  
Three Point Bending ◽  
Composite Sandwich Panels ◽  
Composite Sandwich ◽  
Modes Of Failure ◽  
Deformation Modes

The collapse modes and energy absorption in three-point bending of composite sandwich beams were explored experimentally. Sandwich beams manufactured from woven carbon fibre face sheets encapsulating aluminium foam cores were investigated at 0.001 s-1 and 100 s-1 strain rates. Three modes of failure were observed during deformation: Modes H1, H2 and H3. The direction of core shear played an important role in the energy absorption of the structure. Mode H2 gave rise to the highest specific energy absorption of the composite sandwich beams studied.

Bending response and energy absorption of sandwich beams with novel auxetic honeycomb core

2021 ◽  
Vol 247 ◽  
pp. 113204
Author(s):  
Xuan Zhao ◽  
Lulu Wei ◽  
Dawei Wen ◽  
Guohua Zhu ◽  
Qiang Yu ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Sandwich Beams ◽  
Honeycomb Core ◽  
Bending Response

Use of Nanoindentation to Characterise the Plasma Damage Region in Low-k Dielectric Films

2006 ◽  
Author(s):  
Jon M. Molina-Aldareguia ◽  
Maria R. Elizalde ◽  
Ibon Ocan˜a ◽  
Javier Gil-Sevillano ◽  
Jose´ M. Marti´nez-Esnaola ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Depth Resolution ◽  
Dielectric Materials ◽  
Dynamical Response ◽  
Indentation Modulus ◽  
Depth Sensing ◽  
K Value ◽  
Graded Structure ◽  
Graded Structures ◽  
Low K

The thermo-mechanical robustness of interconnect structures is a key reliability concern for integrated circuits. The introduction of new low dielectric constant (low-k) materials with deteriorated mechanical strength (i.e., Young Modulus decreases exponentially with film porosity, which is needed to lower the k value of the dielectric materials) to meet the RC delay goals increase the risk of mechanical adhesive and/or cohesive failure of the device during packaging or even in service. Therefore, the mechanical properties of low-k dielectrics must be studied in detail. This is made very challenging by the fact that they have submicron thickness and that they often display a graded structure due to the damage introduced by exposure to different plasmas during processing. In this context, we demonstrate that nanoindentation is very well suited to study this type of materials. We will show how conventional depth sensing nanoindentation is of limited value to characterise the extent of the plasma induced damage because this extents just a few tens of nanometres and the graded structure can not be sampled with enough depth resolution. However, nanoindentation in modulus mapping mode can achieve enough depth resolution to characterise such nanoscale graded structures. In this technique, the electrostatic force acting on the indenter tip is sinusoidally modulated, while contact mode imaging at a very small force is performed. The dynamical response is then analyzed to extract the local indentation modulus of the sample at each pixel. By using this technique, we have depth profiled the mechanical properties of the plasma induced damage region of OSG films exposed to different plasmas, by acquiring modulus maps as a function of thickness removed in wear experiments. The results correlate well with the density depth profiles derived from X-Ray Reflectivity measurements.

Processing and Mechanical Properties of Laminar Al2O3-Ni3Al Composites

1994 ◽  
Vol 350 ◽  
Author(s):  
J. H. Schneibel ◽  
K. B. Alexander
Keyword(s):  
Mechanical Properties ◽  
Thin Layer ◽  
Energy Absorption ◽  
Nickel Aluminide ◽  
Intermetallic Alloy ◽  
Interfacial Bonding ◽  
Three Point Bending

AbstractSeveral compositions of the intermetallic alloy Ni3Al were examined with respect to (a) their wetting of Al2O3 and (b) their energy absorption capability in Al2O3/Ni3Al laminates. Wetting is enhanced by small additions of carbon (e.g., 0.1 at. %), and bonding by additions of zirconium (e.g., 1 at. %). Chevron-notched laminate specimens were tested in three-point bending to assess the energy absorption due to the presence of a thin layer of Ni3Al. A nickel aluminide with the composition Ni-22Al-lZr-0.1C-0.1B was found to have a reasonable combination of wetting, adhesion and energy absorption. Interfacial bonding was found to be weak in all laminates.

scholarly journals Bending Behavior of Lightweight Wood-Based Sandwich Beams with Auxetic Cellular Core

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1723 ◽  
Author(s):  
Krzysztof Peliński ◽  
Jerzy Smardzewski
Keyword(s):  
Mechanical Properties ◽  
Experimental Studies ◽  
Numerical Calculations ◽  
Bending Test ◽  
Dissipated Energy ◽  
Sandwich Beams ◽  
Wood Composites ◽  
Three Point Bending ◽  
Good Ability ◽  
Bending Behavior

The work concerns a three-point bending test of beams made of plywood, high density fibre boards, cardboard, and wood-epoxy mass. The goal of the investigation was to determine the effect of thickness and type of wood-based facings on stiffness, strength, ability to absorb, and dissipate the energy of sandwich beams with an auxetic core. The cognitive goal of the work was to demonstrate the possibility of using recycled materials for facings and cores instead of popular wood composites. Experimental studies and numerical calculations were performed on correctly calibrated models. Experimental studies have shown that the beams with HDF facings (E = 1528 MPa, MOR = 12.61 MPa) and plywood facings (E = 1248–1395 MPa, MOR = 8.34–10.40 MPa) have the most favourable mechanical properties. Beams with plywood facings also have a good ability to absorb energy (1.380–1.746 J), but, in this respect, the beams manufactured of HDF (2.223 J) exhibited better capacity. The use of an auxetic core and facings of plywood and cardboard significantly reduces the amount of dissipated energy (0.0093 J, 0.0067 J). Therefore, this type of structures can be used for modeling beams carrying high deflections.

Deformation and Energy Absorption of Composite Sandwich Beams

2014 ◽  
Vol 626 ◽  
pp. 468-473
Author(s):  
Martin Vcelka ◽  
Yvonne Durandet ◽  
Christopher C. Berndt ◽  
Dong Ruan
Keyword(s):  
Energy Absorption ◽  
Sandwich Beam ◽  
Low Velocity Impact ◽  
Sandwich Beams ◽  
Low Velocity ◽  
Three Point Bending ◽  
Fibre Breakage ◽  
Composite Sandwich ◽  
Analytical Expressions ◽  
Composite Face

Experimental observations and data are employed to elucidate the effect of indenter size on the deformation and energy absorption of composite sandwich beams. Unlike metal face sheets that yield and plastically deform to create an intact indentation zone; composite face sheets tend to fail in a brittle manner resulting in fibre breakage that leads to widespread fracture. This mode of failure can dictate how the load is transferred throughout the structure and directly affect the energy absorption character of the composite sandwich beam. Quasi-static and low velocity impact (LVI) three-point bending experiments with various indenter diameters were conducted to observe the interaction between indenter and face sheet and the energy absorption properties. The results are compared with existing analytical expressions.

The Mechanical Properties of Organic Modified Epoxy Resin

2020 ◽  
Vol 43 (3) ◽  
pp. 10-14
Author(s):  
Georgel MIHU ◽  
Claudia Veronica UNGUREANU ◽  
Vasile BRIA ◽  
Marina BUNEA ◽  
Rodica CHIHAI PEȚU ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Epoxy Resin ◽  
Epoxy Matrix ◽  
Epoxy Resins ◽  
Mechanical Tests ◽  
Organic Modification ◽  
Three Point Bending ◽  
Modified Epoxy

Epoxy resins have been presenting a lot of scientific and technical interests and organic modified epoxy resins have recently receiving a great deal of attention. For obtaining the composite materials with good mechanical proprieties, a large variety of organic modification agents were used. For this study gluten and gelatin had been used as modifying agents thinking that their dispersion inside the polymer could increase the polymer biocompatibility. Equal amounts of the proteins were milled together and the obtained compound was used to form 1 to 5% weight ratios organic agents modified epoxy materials. To highlight the effect of these proteins in epoxy matrix mechanical tests as three-point bending and compression were performed.

Static and dynamic response of sandwich beams with lattice and pantographic cores

2021 ◽  
pp. 109963622110338
Author(s):  
Yury Solyaev ◽  
Arseniy Babaytsev ◽  
Anastasia Ustenko ◽  
Andrey Ripetskiy ◽  
Alexander Volkov
Keyword(s):  
Mechanical Performance ◽  
Lattice Structure ◽  
Unit Length ◽  
Experimental Tests ◽  
Plane Geometry ◽  
Sandwich Beams ◽  
Static Tests ◽  
Three Point Bending ◽  
The Core ◽  
The Impact

Mechanical performance of 3d-printed polyamide sandwich beams with different type of the lattice cores is investigated. Four variants of the beams are considered, which differ in the type of connections between the elements in the lattice structure of the core. We consider the pantographic-type lattices formed by the two families of inclined beams placed with small offset and connected by stiff joints (variant 1), by hinges (variant 2) and made without joints (variant 3). The fourth type of the core has the standard plane geometry formed by the intersected beams lying in the same plane (variant 4). Experimental tests were performed for the localized indentation loading according to the three-point bending scheme with small span-to-thickness ratio. From the experiments we found that the plane geometry of variant 4 has the highest rigidity and the highest load bearing capacity in the static tests. However, other three variants of the pantographic-type cores (1–3) demonstrate the better performance under the impact loading. The impact strength of such structures are in 3.5–5 times higher than those one of variant 4 with almost the same mass per unit length. This result is validated by using numerical simulations and explained by the decrease of the stress concentration and the stress state triaxiality and also by the delocalization effects that arise in the pantographic-type cores.

scholarly journals Study on improvement of prefolded energy absorption device to constant resistance and its mechanical properties

2021 ◽  
Vol 104 (3) ◽  
pp. 003685042110368
Author(s):  
Dong An ◽  
Jiaqi Song ◽  
Hailiang Xu ◽  
Jingzong Zhang ◽  
Yimin Song ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Compression Test ◽  
Side Wall ◽  
Concave Side ◽  
Displacement Curve ◽  
Static Compression ◽  
Constant Resistance ◽  
The Impact ◽  
Force Displacement

When the rock burst occurs, energy absorption support is an important method to solve the impact failure. To achieve constant resistance performance of energy absorption device, as an important component of the support, the mechanical properties of one kind of prefolded tube is analyzed by quasi-static compression test. The deformation process of compression test is simulated by ABAQUS and plastic strain nephogram of the numerical model are studied. It is found that the main factors affecting the fluctuation of force-displacement curve is the stiffness of concave side wall. The original tube is improved to constant resistance by changing the side wall. The friction coefficient affects the folding order and form of the energy absorbing device. Lifting the concave side wall stiffness can improve the overall stiffness of energy absorption device and slow down the falling section of force-displacement curve. It is always squeezed by adjacent convex side wall in the process of folding, with large plastic deformation. Compared with the original one, the improved prefolded tube designed in this paper can keep the maximum bearing capacity ( Pmax), increase the total energy absorption ( E), improve the specific energy absorption (SEA), and decrease the variance ( S2) of force-displacement curve.

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