scholarly journals Effect of Absorbent Foam Filling on Mechanical Behaviors of 3D-Printed Honeycombs

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2059
Author(s):  
Leilei Yan ◽  
Keyu Zhu ◽  
Yunwei Zhang ◽  
Chun Zhang ◽  
Xitao Zheng
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Energy Absorption ◽  
Unit Volume ◽  
Honeycomb Structure ◽  
Unit Mass ◽  
Out Of Plane ◽  
Foam Filling ◽  
3D Printed ◽  
Foam Filled

Polylactic acid (PLA) hexagonal honeycomb structures were fabricated by using 3D-printing technology. By filling with absorbent polymethacrylimide (PMI) foam, a novel absorbent-foam-filled 3D-printed honeycomb was obtained. The in-plane (L- and W-direction) and out-of-plane (T-direction) compressive performances were studied experimentally and numerically. Due to absorbent PMI foam filling, the elastic modulus, compressive strength, energy absorption per unit volume, and energy absorption per unit mass of absorbent-foam-filled honeycomb under L-direction were increased by 296.34%, 168.75%, 505.57%, and 244.22%, respectively. Moreover, the elastic modulus, compressive strength, energy absorption per unit volume, and energy absorption per unit mass, under W-direction, also have increments of 211.65%, 179.85, 799.45%, and 413.02%, respectively. However, for out-of-plane compression, the compressive strength and energy absorption per unit volume were enhanced, but the density has also been increased; thus, it is not competitive in energy absorption per unit mass. Failure mechanism and dimension effects of absorbent-foam-filled honeycomb were also considered. The approach of absorbent foam filling made the 3D-printed honeycomb structure more competitive in electromagnetic wave stealth applications, while acting simultaneously as load-carrying structures.

An experimental investigation on mechanical performances of 3D printed lightweight ABS pipes with different cellular wall thickness

2021 ◽  
Vol 15 (2) ◽  
pp. 8169-8177
Author(s):  
Berkay Ergene ◽  
İsmet ŞEKEROĞLU ◽  
Çağın Bolat ◽  
Bekir Yalçın
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
Wall Thickness ◽  
Lattice Structure ◽  
Honeycomb Structure ◽  
Cellular Structures ◽  
Compression Tests ◽  
Absorbed Energy ◽  
Great Opportunity ◽  
3D Printed

In recent years, cellular structures have attracted great deal of attention of many researchers due to their unique properties like exhibiting high strength at low density and great energy absorption. Also, the applications of cellular structures (or lattice structures) such as wing airfoil, tire, fiber and implant, are mainly used in aerospace, automotive, textile and biomedical industries respectively. In this investigation, the idea of using cellular structures in pipes made of acrylonitrile butadiene styrene (ABS) material was focused on and four different pipe types were designed as honeycomb structure model, straight rib pattern model, hybrid version of the first two models and fully solid model. Subsequently, these models were 3D printed by using FDM method and these lightweight pipes were subjected to compression tests in order to obtain stress-strain curves of these structures. Mechanical properties of lightweight pipes like elasticity modulus, specific modulus, compressive strength, specific compressive strength, absorbed energy and specific absorbed energy were calculated and compared to each other. Moreover, deformation modes were recorded during all compression tests and reported as well. The results showed that pipe models including lattice wall thickness could be preferred for the applications which don’t require too high compressive strength and their specific energy absorption values were notably capable to compete with fully solid pipe structures. In particular, rib shape lattice structure had the highest elongation while the fully solid one possessed worst ductility. Lastly, it is pointed out that 3D printing method provides a great opportunity to have a foresight about production of uncommon parts by prototyping.

Energy Absorption Properties of Folded Honeycomb Structure Consisting of Corrugated Paperboard

2010 ◽  
Vol 160-162 ◽  
pp. 1488-1493
Author(s):  
Dong Mei Wang ◽  
Qiang Hua Liao ◽  
Zi You Bai
Keyword(s):  
Relative Density ◽  
Energy Absorption ◽  
Unit Volume ◽  
Honeycomb Structure ◽  
Unit Mass ◽  
Absorption Properties

Many experiments and analysis of folded honeycomb consisting of corrugated paperboards show that the use of linerboard can increase the energy absorption and weight of folded honeycombs. However, it reduces the energy absorption per unit volume and unit mass and increases the cushioning cost either. For the same corrugate shape, reducing corrugated size will increase the weight of folded honeycombs, and changing corrugated size will change the energy absorption per unit volume, but it can not change the cushioning cost. At a low relative density of corrugated sandwiches, the energy absorption per unit volume and unit mass rapidly increases, and the cushioning cost decreases when the relative density of corrugated sandwiches rises. While at a higher relative density, the energy absorption per unit volume and unit mass does not effectively increase with relative density of corrugated sandwiches. However, the cushioning cost may increases. Therefore, when designing the corrugated sandwich size, we can change the thickness of corrugate basis-paper or the corrugated size to change the relative density of corrugated sandwiches and the cushioning cost.

scholarly journals Degradation of Mechanical Behavior of Sandstone under Freeze-Thaw Conditions with Different Low Temperatures

2021 ◽  
Vol 11 (22) ◽  
pp. 10653
Author(s):  
Jingwei Gao ◽  
Chao Xu ◽  
Yan Xi ◽  
Lifeng Fan
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Mechanical Behavior ◽  
Energy Absorption ◽  
Uniaxial Compressive Strength ◽  
Dynamic Strength ◽  
Freezing Temperature ◽  
P Wave ◽  
Freeze Thaw ◽  
P Wave Velocity

This study investigated the effects of freezing temperature under freeze-thaw cycling conditions on the mechanical behavior of sandstone. First, the sandstone specimens were subjected to 10-time freeze-thaw cycling treatments at different freezing temperatures (−20, −40, −50, and −60 °C). Subsequently, a series of density, ultrasonic wave, and static and dynamic mechanical behavior tests were carried out. Finally, the effects of freezing temperature on the density, P-wave velocity, stress–strain curves, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption of sandstone were discussed. The results show that the density slightly decreases as temperature decreases, approximately by 1.0% at −60 °C compared with that at 20 °C. The P-wave velocity, static and dynamic uniaxial compressive strength, static elastic modulus, and dynamic energy absorption obviously decrease. As freezing temperature decreases from 20 to −60 °C, the static uniaxial compressive strength, static elastic modulus, dynamic strength, and dynamic energy absorption of sandstone decrease by 16.8%, 21.2%, 30.8%, and 30.7%, respectively. The dynamic mechanical behavior is more sensitive to the freezing temperature during freeze-thawing cycling compared with the static mechanical behavior. In addition, a higher strain rate can induce a higher dynamic strength and energy absorption.

scholarly journals In Vivo Reconstruction of the Acetabular Bone Defect by the Individualized Three-Dimensional Printed Porous Augment in a Swine Model

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Jun Fu ◽  
Yi Xiang ◽  
Ming Ni ◽  
Xiaojuan Qu ◽  
Yonggang Zhou ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Bone Defect ◽  
Bone Ingrowth ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Acetabular Bone ◽  
Acetabular Bone Defect ◽  
3D Printed ◽  
Matching Degree

Background and Purpose. This study established an animal model of the acetabular bone defect in swine and evaluated the bone ingrowth, biomechanics, and matching degree of the individualized three-dimensional (3D) printed porous augment. Methods. As an acetabular bone defect model created in Bama miniswine, an augment individually fabricated by 3D print technique with Ti6Al4V powders was implanted to repair the defect. Nine swine were divided into three groups, including the immediate biomechanics group, 12-week biomechanics group, and 12-week histological group. The inner structural parameters of the 3D printed porous augment were measured by scanning electron microscopy (SEM), including porosity, pore size, and trabecular diameter. The matching degree between the postoperative augment and the designed augment was assessed by CT scanning and 3D reconstruction. In addition, biomechanical properties, such as stiffness, compressive strength, and the elastic modulus of the 3D printed porous augment, were measured by means of a mechanical testing machine. Moreover, bone ingrowth and implant osseointegration were histomorphometrically assessed. Results. In terms of the inner structural parameters of the 3D printed porous augment, the porosity was 55.48 ± 0.61 % , pore size 319.23 ± 25.05   μ m , and trabecular diameter 240.10 ± 23.50   μ m . Biomechanically, the stiffness was 21464.60 ± 1091.69   N / mm , compressive strength 231.10 ± 11.77   MPa , and elastic modulus 5.35 ± 0.23   GPa , respectively. Furthermore, the matching extent between the postoperative augment and the designed one was up to 91.40 ± 2.83 % . Besides, the maximal shear strength of the 3D printed augment was 929.46 ± 295.99   N immediately after implantation, whereas the strength was 1521.93 ± 98.38   N 12 weeks after surgery ( p = 0.0302 ). The bone mineral apposition rate (μm per day) 12 weeks post operation was 3.77 ± 0.93   μ m / d . The percentage bone volume of new bone was 22.30 ± 4.51 % 12 weeks after surgery. Conclusion. The 3D printed porous Ti6Al4V augment designed in this study was well biocompatible with bone tissue, possessed proper biomechanical features, and was anatomically well matched with the defect bone. Therefore, the 3D printed porous Ti6Al4V augment possesses great potential as an alternative for individualized treatment of severe acetabular bone defects.

scholarly journals Preparation of Nanocellulose Aerogel from the Poplar (Populus tomentosa) Catkin Fiber

Forests ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 749 ◽  
Author(s):  
Wu ◽  
Sun ◽  
Wu ◽  
Shi ◽  
Chen ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Honeycomb Structure ◽  
Populus Tomentosa ◽  
Raw Material ◽  
Sodium Chlorite ◽  
Maximum Value ◽  
Ultrasonic Time ◽  
Naoh Solution ◽  
The Difference

: The effects of chemical pretreatment on the purification of poplar (Populus tomentosa) catkin fiber and the effect of ultrasonic time for the microfibrillarization of poplar catkin fiber (PCF) were studied. The nanocellulose aerogels were prepared by freeze drying the cellulose solutions. The density, porosity, micro morphology, thermal stability and mechanical properties of the aerogels were analyzed. It was found that the dewaxing time of PCF is shorter than that of unsonicated nanocellulose. After the treatment of 0.5 wt% sodium chlorite for 2 h, the lignin of PCF was removed. After the chemical purification, the PCF was treated with 2 and 5 wt% NaOH solution and ultrasonicated for 5 and 10 min, respectively. When the ultrasonic time was 10 min, the diameter of the nanocellulose was 20-25 nm. When the ultrasonic time was 5 min, the aerogels with porous honeycomb structure can be prepared by using the nanocellulose sol of PCF as raw material. The density of the aerogels was only 0.3-0.4 mg/cm3 and the porosities of the aerogels were all larger than 99%. The difference between the pyrolysis temperature of aerogels was small, the elastic modulus of aerogels was 30–52 kPa, and the compressive strength was 22–27 kPa. With the increase of the concentration of NaOH solution (5 wt%) and ultrasonic time (10 min), the elastic modulus of aerogels increased gradually and reached the maximum value of 52 kPa, while the compressive strength reached the maximum value of 27 kPa when the PCF being treated in 5 wt% NaOH solution and was ultrasonicated for 5 min.

Quasi-Static Axial Compression Behavior and Energy Absorption Evaluation of Steel Foam-Filled Tubes

2020 ◽  
Vol 993 ◽  
pp. 863-868
Author(s):  
Chao Qun Guo ◽  
Tian Yao Wang ◽  
Tian Xiang Yuan ◽  
De Lin Ma ◽  
Yun Zhou ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Energy Absorption ◽  
Unit Volume ◽  
Deformation Mode ◽  
Absorbed Energy ◽  
Compression Behavior ◽  
Plateau Stress ◽  
Compressive Performance ◽  
Foam Filled ◽  
Steel Foam

The aim of this paper is to study the quasi-static axial compressive performance of newly developed steel foam-filled tubes (SFFTs). The energy absorption capability of steel foam-filled tubes was assessed. The results show that steel foam-filled tubes collapse in the axisymmetric-concertina deformation mode. The plateau stress of the plastic deformation of the steel foam-filled tubes decreases with the increase of porosity of steel foams, and is significantly higher than the sum of the identical steel foam and aluminum tube. The absorbed energy per unit volume of the steel foam-filled tubes is 8%~ 15% higher than the sum of those of identical aluminum tubes and steel foams with porosity ranging from 65% to 80%.

Experimental and Numerical Analysis of Qinling Mountain Engineered Rocks during Pulse-Shaped SHPB Test

2015 ◽  
Vol 16 (3-4) ◽  
pp. 165-171
Author(s):  
Shi Liu ◽  
Jinyu Xu
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Strain Rate ◽  
Energy Absorption ◽  
Absorption Rate ◽  
Failure Modes ◽  
Dynamic Compression ◽  
Peak Strain ◽  
Compression Stress ◽  
Dynamic Compressive Strength

AbstractIn order to study the dynamic compression mechanical properties of engineering rock under high strain rate （100~102 S−1）loads, dynamic compression tests of three common engineering rocks (marble, sandstone and granite) taken from the Qinling Mountain are studied subjected to five different kinds of shock air pressure using Φ 100 mm split Hopkinson pressure bar test system improved with purple copper waveform shaper. The dynamic compression stress-strain curves, dynamic compressive strength, peak strain, energy absorption rate and elastic modulus of three rocks variation with strain rate are researched. The dynamic compression failure modes under different strain rates are analyzed. Then the three-dimensional numerical simulations of waveform shaper shaping effects and stress wave propagation in the SHPB tests are carried out to reproduce the test results. The research results show that the dynamic compression stress-strain curves show certain discreteness, and there is an obvious rebound phenomenon after the peak. With the increase in strain rate, the dynamic compressive strength, peak strain and energy absorption rate are all in a certain degree of increase, but the elastic modulus have no obvious change trend. Under the same strain rate, the dynamic compressive strength of granite is greatest while of sandstone is least. With the increase in strain rate, the margin of increase in peak strain and energy absorption rate of granite is greatest while of sandstone is least. The failure modes of the sample experience a developing process from outside to inside with the increase of strain rate.

Effects of aluminum foam filling on the low-velocity impact response of sandwich panels with corrugated cores

2018 ◽  
Vol 22 (4) ◽  
pp. 929-947 ◽  
Author(s):  
LL Yan ◽  
B Yu ◽  
B Han ◽  
QC Zhang ◽  
TJ Lu ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Aluminum Foam ◽  
Sandwich Panel ◽  
Absorption Capacity ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Energy Absorption Capacity ◽  
Core Member ◽  
Foam Filling ◽  
Foam Filled

In this study, a closed-cell aluminum foam was filled into the interspaces of a sandwich panel with corrugated cores to form a composite structure. The novel structure is expected to have enhanced foam-filled cores with high specific strength and energy absorption capacity. An out-of-plane compressive load under low-velocity impact was experimentally and numerically carried out on both the empty and foam-filled sandwich panels as well as on the aluminum foam. It is found that the empty corrugated sandwich panel has poor energy absorption capacity due to the core member buckling compared to that of the aluminum foam. However, by the filling of the aluminum foam, the impact load resistance of the corrugated panel was increased dramatically. The loading-time response of the foam-filled panel performs a plateau region like the aluminum foam, which has been proved to be an excellent energy absorption material. Numerical results demonstrated that the aluminum foam filling can decrease the corrugated core member defects sensitivity and increase its stability dramatically. The plastic energy dissipation of the core member for the foam-filled panel is much higher than that of the empty one due to the reduced buckling wavelength caused by the aluminum foam filling.

Experimental and numerical study of buckling behavior of foam-filled honeycomb core sandwich panels considering viscoelastic effects

2020 ◽  
pp. 109963622097516
Author(s):  
M Safarabadi ◽  
M Haghighi-Yazdi ◽  
MA Sorkhi ◽  
A Yousefi
Keyword(s):  
Energy Absorption ◽  
Viscoelastic Properties ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Face Sheet ◽  
Honeycomb Core ◽  
Buckling Behavior ◽  
Foam Filling ◽  
Foam Filled ◽  
Composite Face

Honeycomb sandwich panels are widely used in marine, aerospace, automotive and shipbuilding industries. High strength to weight and excellent energy absorption are features that make these structures unique. Foam filling the honeycomb core enhances the mechanical properties of sandwich panels considerably. In the present study, the buckling behavior of Nomex honeycomb core/glass-epoxy face sheet sandwich panel for both bare and foam-filled honeycomb core is investigated numerically and experimentally, considering the viscoelastic properties of the sandwich panel. Indeed, the viscoelastic properties of the composite face sheet and foam are determined by relaxation test and are implemented in ABAQUS using VUmat code. The finite element method is also performed using ABAQUS to model the buckling behavior of the sandwich panel incorporating both elastic and viscoelastic material behaviour. The effects of composite face sheet lay-up, core thickness, core cell size, and foam filling are also evaluated. The experimental and numerical results show that the foam increases the critical buckling load and energy absorption.

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