Improving cushioning properties of a 3D weft knitted spacer fabric in a novel design with NiTi monofilaments

2018 ◽  
Vol 49 (10) ◽  
pp. 1389-1410 ◽  
Author(s):  
Mohsen Hamedi ◽  
Parisa Salimi ◽  
Nima Jamshidi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Mechanical Stress ◽  
Energy Absorption ◽  
Absorption Capacity ◽  
Daily Activities ◽  
Energy Absorption Capacity ◽  
Static Compression ◽  
Spacer Fabric ◽  
Novel Design

Cushioning pads alleviate the effects of mechanical stress on the human body due to impacts and daily activities. One relevant application for such pads is orthopedic insoles used for diabetic foot to improve energy absorption and reduce stress gradient by using suitable materials and structures. This article considers a novel design that improves the energy absorption capabilities of cushioning pads. Experiments were conducted to evaluate the properties of the designed weft knitted spacer fabrics. Six groups of samples were knitted in which steel, polyamide, and shape memory alloy materials were utilized as spacer monofilament. Stress–strain, energy absorption and efficiency diagrams were obtained following the quasi-static compression tests carried out on the samples. Three investigation groups were adopted to evaluate the effect of the spacer monofilament material, diameter, and slope on energy absorption capacity. It was determined that shape memory alloy monofilament with 0.1 mm diameter was the optimum configuration to be utilized as spacer yarn in a typical 3D weft knitted fabric. It was also concluded that higher-inclined spacer monofilament in spacer fabric was the optimum choice for knitting cushioning pads as it absorbed more energy. The energy absorption capacity of the optimum design of spacer fabric obtained in this study, increased by a factor of 2.4 compared with commercial polyamide pads. This design can be utilized in any cushioning pad exposed to high mechanical stress due to impact, sports and daily activities.

3D-Printed Bio-inspired Zero Poisson’s Ratio Graded Metamaterials with High Energy Absorption Performance

2022 ◽  
Author(s):  
Ramin Hamzehei ◽  
Ali Zolfagharian ◽  
Soheil Dariushi ◽  
Mahdi Bodaghi
Keyword(s):  
Cell Wall ◽  
Energy Absorption ◽  
Poisson’S Ratio ◽  
High Energy ◽  
Absorption Capacity ◽  
Poisson's Ratio ◽  
Base Pairs ◽  
Energy Absorption Capacity ◽  
Static Compression ◽  
Unit Cells

Abstract This study aims at introducing a number of two-dimensional (2D) re-entrant based zero Poisson’s ratio (ZPR) graded metamaterials for energy absorption applications. The metamaterials’ designs are inspired by the 2D image of a DNA molecule. This inspiration indicates how a re-entrant unit cell must be patterned along with the two orthogonal directions to obtain a ZPR behavior. Also, how much metamaterials’ energy absorption capacity can be enhanced by taking slots and horizontal beams into account with the inspiration of the DNA molecule’s base pairs. The ZPR metamaterials comprise multi-stiffness unit cells, so-called soft and stiff re-entrant unit cells. The variability in unit cells’ stiffness is caused by the specific design of the unit cells. A finite element analysis (FEA) is employed to simulate the deformation patterns of the ZPRs. Following that, meta-structures are fabricated with 3D printing of TPU as hyperelastic materials to validate the FEA results. A good correlation is observed between FEA and experimental results. The experimental and numerical results show that due to the presence of multi-stiffness re-entrant unit cells, the deformation mechanisms and the unit cells’ densifications are adjustable under quasi-static compression. Also, the structure designed based on the DNA molecule’s base pairs, so-called structure F''', exhibits the highest energy absorption capacity. Apart from the diversity in metamaterial unit cells’ designs, the effect of multi-thickness cell walls is also evaluated. The results show that the diversity in cell wall thicknesses leads to boosting the energy absorption capacity. In this regard, the energy absorption capacity of structure ‘E’ enhances by up to 33% than that of its counterpart with constant cell wall thicknesses. Finally, a comparison in terms of energy absorption capacity and stability between the newly designed ZPRs, traditional ZPRs, and auxetic metamaterial is performed, approving the superiority of the newly designed ZPR metamaterials over both traditional ZPRs and auxetic metamaterials.

scholarly journals Cyclic Behavior of Masonry Shear Walls Retrofitted with Engineered Cementitious Composite and Pseudoelastic Shape Memory Alloy

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 511
Author(s):  
Alireza Tabrizikahou ◽  
Mieczysław Kuczma ◽  
Magdalena Łasecka-Plura ◽  
Ehsan Noroozinejad Noroozinejad Farsangi
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shear Walls ◽  
Absorption Capacity ◽  
Cyclic Behavior ◽  
Masonry Walls ◽  
Cementitious Composite ◽  
Energy Absorption Capacity ◽  
Engineered Cementitious Composite ◽  
Mesh Density

The behavior of masonry shear walls reinforced with pseudoelastic Ni–Ti shape memory alloy (SMA) strips and engineered cementitious composite (ECC) sheets is the main focus of this paper. The walls were subjected to quasi-static cyclic in-plane loads and evaluated by using Abaqus. Eight cases of strengthening of masonry walls were investigated. Three masonry walls were strengthened with different thicknesses of ECC sheets using epoxy as adhesion, three walls were reinforced with different thicknesses of Ni–Ti strips in a cross form bonded to both the surfaces of the wall, and one was utilized as a reference wall without any reinforcing element. The final concept was a hybrid of strengthening methods in which the Ni–Ti strips were embedded in ECC sheets. The effect of mesh density on analytical outcomes is also discussed. A parameterized analysis was conducted to examine the influence of various variables such as the thickness of the Ni–Ti strips and that of ECC sheets. The results show that using the ECC sheet in combination with pseudoelastic Ni–Ti SMA strips enhances the energy absorption capacity and stiffness of masonry walls, demonstrating its efficacy as a reinforcing method.

scholarly journals Study on aluminum foam as a filler material for impact limiter of spent fuel transport cask

2018 ◽  
Vol 238 ◽  
pp. 05006
Author(s):  
Zhongfang Li ◽  
Siyi Yang ◽  
Haile Xu ◽  
Yukun An
Keyword(s):  
Energy Absorption ◽  
Aluminum Foam ◽  
Absorption Capacity ◽  
Filler Material ◽  
Main Function ◽  
Spent Fuel ◽  
Energy Absorption Capacity ◽  
Static Compression ◽  
Unit Energy ◽  
Quasi Static Compression

Spent fuel transport cask is a significant carrier of spent fuel transport. The main function of impact limiters installed at both ends of the container is to absorb energy and limit overload to ensure the integrity of the structure. The quasi-static compression process of aluminum foam was simulated on the platform of ANSYS Workbench. Foam aluminum was prepared by melt foaming method and quasi static compression test was carried out. The experimental results show that the deformation process of aluminum foam is basically the same as that of experiment, and the aluminum foam has good compressive and energy absorption properties. The yield stress (σys) and plateau stress (σpl) of aluminum foam with density of 0.64 g/cm3 can reach 8.26 MPa and 11.11 MPa respectively, and the energy absorption capacity (WEA) and unit energy absorption capacity (WSEA) can reach 6.31 x 103KJ/m3 and 9.87 KJ/Kg respectively, and the difference between the foam with density of 0.61g/cm3 and its various properties is very small. It can be concluded that the aluminum foam in a certain density range has roughly the same performance, and it also reflected the stability of aluminum foam's performance. Additionally, aluminum foam is an isotropic material, which can overcome directional limitation when used as shock absorber filler material for spent fuel transport cask.

scholarly journals Deformation Behaviors and Energy Absorption of Composite Re-Entrant Honeycomb Cylindrical Shells under Axial Load

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7129
Author(s):  
Nanfang Ma ◽  
Qingtian Deng ◽  
Xinbo Li
Keyword(s):  
Energy Absorption ◽  
Mechanical Performance ◽  
Cylindrical Shells ◽  
Single Layer ◽  
Absorption Capacity ◽  
Low Velocity ◽  
Energy Absorption Capacity ◽  
Static Compression ◽  
Layer Composite ◽  
Deformation Behaviors

Composite materials and re-entrant honeycomb structures have superior mechanical performance in energy absorption capacity. Inspired by laminate composite layers, single-layer re-entrant honeycomb cylindrical shells (RHCSs) with different orientations were established, and composite RHCSs were proposed by combining the single-layer RHCSs with different orientations. The deformation behaviors of single layer RHCSs under quasi-static compression were studied by experimentation, and single-layer RHCSs with varying orientations did not show negative Poisson’s ratio effects. The energy absorption capacity of single-layer and composite RHCSs was researched using simulation. To analyze the energy absorption capacity, we determined the plateau stress, the mean force and specific energy absorption of single-layer and multi-layer composite RHCSs under different impact velocities; the following conclusions were obtained: compared with the single-layer RHCSs, the multi-layer composite RHCSs, which had the same size, the energy absorption capacity improved significantly under the same impact velocities. The energy absorption capacity of the multi-layer composite RHCSs improved with increasing number of layers under low velocity.

Experimental Analyses on Energy Absorption Property of Aluminum Honeycomb under Out-of-Plane Compression

2015 ◽  
Vol 778 ◽  
pp. 18-23
Author(s):  
Jing Hui Zhao ◽  
Jian Feng Wang ◽  
Tao Liu ◽  
Na Yang ◽  
Wen Jie Duan ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Specific Energy ◽  
Absorption Capacity ◽  
Dynamic Impact ◽  
Energy Absorption Capacity ◽  
Static Compression ◽  
Specific Energy Absorption ◽  
Out Of Plane ◽  
Aluminum Honeycomb ◽  
Plane Compression

Aluminum honeycomb is a lightweight material with high strength and strong capacity of energy absorption. In order to research energy absorption characteristic of aluminum honeycomb material, quasi-static and dynamic out-of-plane compression experiments are carried out on a double-layer aluminum honeycomb impact attenuator of one FSAE racing car. Plateau stress (PS), specific load (SL), mass specific energy absorption (MSEA), volume specific energy absorption (VSEA) and other parameters of the tested aluminum honeycomb under both quasi-static and dynamic impact conditions are analyzed. The results show that the tested aluminum honeycomb impact attenuator has good energy absorption capacity to meet the collision requirements. Furthermore, under the condition of dynamic impact, the energy absorption capacity of this honeycomb improves compared with that under the condition of quasi static compression.

scholarly journals FEA and Quasi-static Test on Energy Absorption Characteristic of Space Orthogonal Concave Honeycomb Structure with Negative Poisson’s Ratio

2022 ◽  
Vol 2160 (1) ◽  
pp. 012064
Author(s):  
Nan Sun ◽  
Shuai Wang ◽  
Kaifa Zhou ◽  
Wenyi Ma ◽  
Bohao Xu
Keyword(s):  
Energy Absorption ◽  
Poisson’S Ratio ◽  
Honeycomb Structure ◽  
Absorption Capacity ◽  
Poisson's Ratio ◽  
Absorption Characteristic ◽  
Negative Poisson’S Ratio ◽  
Energy Absorption Capacity ◽  
Static Compression ◽  
Negative Poisson's Ratio

Abstract As a representative of metamaterials, negative Poisson’s ratio (NPR) material possesses special mechanical properties such as expansion, negative compression ratio and so forth. As a result, it is widely used in the fields of vehicles, aerospace, et al. In this paper, a novel space orthogonal concave honeycomb structure (OC) is designed based on traditional concave honeycomb structure (CHS). In order to explore the influence rule of OC structure on the deformation and energy absorption capacity of crash box under low-speed collision, mechanical analysis and parameter research on OC structure are conducted through quasi-static compression test and numerical simulation. The results suggest that the finite element results of OC structure fit well with the experimental results, and the FEM is highly credible. In addition, the novel OC sandwich structure can effectively enhance the deformation capacity and improve the energy absorption performance of the crash box. When the wall thickness ? of OC structure is 1mm and angle ? is 50°, the deformation and energy absorption capacity of the crash box increased by 25.6% and 19.3% respectively.

scholarly journals Scalable Output Linear Actuators, a Novel Design Concept Using Shape Memory Alloy Wires Driven by Fluid Temperature

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Andres Osorio Salazar ◽  
Yusuke Sugahara ◽  
Daisuke Matsuura ◽  
Yukio Takeda
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Angular Position ◽  
Scale Factor ◽  
Design Concept ◽  
Fluid Temperature ◽  
Step Size ◽  
Simple Method ◽  
Output Characteristics ◽  
Novel Design

In this paper, the concept of scalability for actuators is introduced and explored, which is the capability to freely change the output characteristics on demand: displacement and force for a linear actuator, angular position and torque for a rotational actuator. This change can either be used to obtain power improvement (with a constant scale factor), or to improve the usability of a robotic system according to variable conditions (with a variable scale factor). Some advantages of a scalable design include the ability to adapt to changing environments, variable resolution of step size, ability to produce designs that are adequate for restricted spaces or that require strict energy efficiency, and intrinsically safe systems. Current approaches for scalability in actuators have shortcomings: the method to achieve scalability is complex, so obtaining a variable scaling factor is challenging, or they cannot scale both output characteristics simultaneously. Shape Memory Alloy (SMA) wire-based actuators can overcome these limitations, because its two output characteristics, displacement and force, are physically independent from each other. In this paper we present a novel design concept for linear scalable actuators that overcome SMA design and scalability limitations by using a variable number of SMA wires mechanically in parallel, immersed in a liquid that transmits heat from a separate heat source (wet activation). In this concept, more wires increase the maximum attainable force, and longer wires increase the maximum displacement. Prototypes with different number of SMA wires were constructed and tested in isometric experiments to determine force vs. temperature behavior and time response. The heat-transmitting liquid was either static or flowing using pumps. Scalability was achieved with a simple method in all tested prototypes with a linear correlation of maximum force to number of SMA wires. Flowing heat transmission achieved higher actuation bandwidth.

Numerical and experimental investigation for enhancing the energy absorption capacity of the novel three-dimensional printed sandwich structures

2021 ◽  
pp. 146442072199749
Author(s):  
H Geramizadeh ◽  
S Dariushi ◽  
S Jedari Salami
Keyword(s):  
Energy Absorption ◽  
Sandwich Structures ◽  
Three Dimensional ◽  
Absorption Capacity ◽  
The Novel ◽  
Energy Absorption Capacity ◽  
Fused Deposition ◽  
Honeycomb Sandwich ◽  
Out Of Plane ◽  
Vertical Walls

The current study focuses on designing the optimal three-dimensional printed sandwich structures. The main goal is to improve the energy absorption capacity of the out-of-plane honeycomb sandwich beam. The novel Beta VI and Alpha VI were designed in order to achieve this aim. In the Beta VI, the connecting curves (splines) were used instead of the four diagonal walls, while the two vertical walls remained unchanged. The Alpha VI is a step forward on the Beta VI, which was promoted by filleting all angles among the vertical walls, created arcs, and face sheets. The two offered sandwich structures have not hitherto been provided in the literature. All models were designed and simulated by the CATIA and ABAQUS, respectively. The three-dimensional printer fabricated the samples by fused deposition modeling technique. The material properties were determined under tensile, compression, and three-point bending tests. The results are carried out by two methods based on experimental tests and finite element analyses that confirmed each other. The achievements provide novel insights into the determination of the adequate number of unit cells and demonstrate the energy absorption capacity of the Beta VI and Alpha VI are 23.7% and 53.9%, respectively, higher than the out-of-plane honeycomb sandwich structures.

scholarly journals Dynamic crushing behavior of closed-cell aluminum foams based on different space-filling unit cells

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
S. Talebi ◽  
R. Hedayati ◽  
M. Sadighi
Keyword(s):  
Surface Area ◽  
Dynamic Behavior ◽  
Energy Absorption ◽  
Peak Stress ◽  
Absorption Capacity ◽  
Unit Cell ◽  
Lattice Structures ◽  
Energy Absorption Capacity ◽  
Closed Cell ◽  
Unit Cells

AbstractClosed-cell metal foams are cellular solids that show unique properties such as high strength to weight ratio, high energy absorption capacity, and low thermal conductivity. Due to being computation and cost effective, modeling the behavior of closed-cell foams using regular unit cells has attracted a lot of attention in this regard. Recent developments in additive manufacturing techniques which have made the production of rationally designed porous structures feasible has also contributed to recent increasing interest in studying the mechanical behavior of regular lattice structures. In this study, five different topologies namely Kelvin, Weaire–Phelan, rhombicuboctahedron, octahedral, and truncated cube are considered for constructing lattice structures. The effects of foam density and impact velocity on the stress–strain curves, first peak stress, and energy absorption capacity are investigated. The results showed that unit cell topology has a very significant effect on the stiffness, first peak stress, failure mode, and energy absorption capacity. Among all the unit cell types, the Kelvin unit cell demonstrated the most similar behavior to experimental test results. The Weaire–Phelan unit cell, while showing promising results in low and medium densities, demonstrated unstable behavior at high impact velocity. The lattice structures with high fractions of vertical walls (truncated cube and rhombicuboctahedron) showed higher stiffness and first peak stress values as compared to lattice structures with high ratio of oblique walls (Weaire–Phelan and Kelvin). However, as for the energy absorption capacity, other factors were important. The lattice structures with high cell wall surface area had higher energy absorption capacities as compared to lattice structures with low surface area. The results of this study are not only beneficial in determining the proper unit cell type in numerical modeling of dynamic behavior of closed-cell foams, but they are also advantageous in studying the dynamic behavior of additively manufactured lattice structures with different topologies.

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