Study on buffering characteristics of expanded polyvinyl alcohol influenced by temperature and humidity

2016 ◽  
Vol 54 (1) ◽  
pp. 73-86 ◽  
Author(s):  
Hong Zhu ◽  
Dongmei Wang
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Polyvinyl Alcohol ◽  
Energy Absorption ◽  
Static Compression ◽  
Liquid Retention ◽  
Temperature And Humidity ◽  
Liquid Products ◽  
Different Temperatures ◽  
Wet Condition

Expanded polyvinyl alcohol is regarded as excellent buffering and leak-proof packaging material of liquid products due to its characteristics such as good liquid absorption and liquid retention properties, good mechanical properties under dry condition, and good rebound resilience under wet condition. Through static compression experiment, this study analyzed the mechanical properties and energy absorption properties of expanded polyvinyl alcohol with different densities under different temperatures and relative humidity. The experimental results showed that the effect of ambient temperature and humidity on expanded polyvinyl alcohol performance was mainly to change its internal moisture. The initial elastic modulus, plateau stress, and energy absorption value per unit volume of expanded polyvinyl alcohol increased as the density increased, the relative humidity decreased, or temperature increased. The above research can provide reference for applications of expanded polyvinyl alcohol on buffering packaging in actual logistic environment.

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.

scholarly journals Effect of polymer content and temperature on mechanical properties of lightweight polymer concrete

2020 ◽  
Author(s):  
Khashayar Jafari
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Weight Ratio ◽  
High Strength ◽  
Polymer Concrete ◽  
Polymer Content ◽  
Experimental Parameters ◽  
Different Temperatures ◽  
Non Destructive ◽  
Polymer Ratio

This study investigates the mechanical properties of lightweight polymer concrete (LWPC) containing four different polymer ratios (10%, 12%, 14%, and 16%) tested at three different temperatures (−15 °C, +5 °C, and +25 °C) using destructive and non-destructive tests. In addition, a series of expressions are suggested to predict the splitting-tensile, flexural and impact strength of LWPC based on the main parameters and compressive strength. The analysis of variance (ANOVA) method was also used to determine relative contributions of the experimental parameters. The results of the destructive tests show that increasing the polymer ratio caused an increase in the compressive, splitting-tensile, and impact strengths, and energy absorption of LWPC. With decreasing the temperature from +25 °C to −15 °C, the compressive, splitting-tensile, flexural strengths, and elastic modulus (EM) increased, whereas the energy absorption, impact energy, and ductility decreased. The findings of this research provide beneficial information toward understanding the behavior of LWPC and its safe use in engineering applications where a material of high strength-to-weight ratio is required.

Effect of Temperature and Humidity on Measuring Ionization Current Inside Contaminated Pipes

2013 ◽  
Author(s):  
Pingchuan Li ◽  
Xianguo Tuo ◽  
Mingzhe Liu ◽  
Jun Ren ◽  
Qibiao Wang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Long Range ◽  
Regression Method ◽  
Experimental Results ◽  
Ion Current ◽  
Effect Of Temperature ◽  
Multiple Regression Method ◽  
Temperature And Humidity ◽  
Different Temperatures ◽  
Effects Of Temperature

This paper reported the experimental results of ion current under different temperatures and relative humidity using long range alpha detector (LRAD). An approximation relation between the measuring values, temperatures and relative humidity has been obtained using the linear multiple regression method. The experimental results have shown that the measuring values decrease with the increase of temperature and humidity. The influence of humidity on results outweighs that of temperatures. And both temperature and humidity are obviously negative correlated with measured values. Further experiments will be performed to confirm the coupling effects of temperature and humidity and reported later.

scholarly journals Compressive Properties of Functionally Graded Bionic Bamboo Lattice Structures Fabricated by FDM

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4410
Author(s):  
Zhou Wen ◽  
Ming Li
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Honeycomb Structure ◽  
Absorption Capacity ◽  
Functionally Graded ◽  
Honeycomb Lattice ◽  
Lattice Structures ◽  
Compression Tests ◽  
Uniform Lattice ◽  
Static Compression

Bionic design is considered a promising approach to improve the performance of lattice structures. In this work, bamboo-inspired cubic and honeycomb lattice structures with graded strut diameters were designed and manufactured by 3D printing. Uniform lattice structures were also designed and fabricated for comparison. Quasi-static compression tests were conducted on lattice structures, and the effects of the unit cell and structure on the mechanical properties, energy absorption and deformation mode were investigated. Results indicated that the new bionic bamboo structure showed similar mechanical properties and energy absorption capacity to the honeycomb structure but performed better than the cubic structure. Compared with the uniform lattice structures, the functionally graded lattice structures showed better performance in terms of initial peak strength, compressive modulus and energy absorption.

scholarly journals Dynamic Mechanical Behavior of Hierarchical Resin Honeycomb by 3D Printing

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 19
Author(s):  
Huan Hong ◽  
Menglei Hu ◽  
Liansong Dai
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Mechanical Behavior ◽  
Energy Absorption ◽  
Dynamic Compression ◽  
Hierarchical Level ◽  
Absorption Properties ◽  
Static Compression ◽  
Collapse Strength ◽  
Different Levels

In this paper, surface projection micron stereo-lithography technology (PμSL) by 3D printing was used to prepare two resin honeycomb materials with different levels, and the mechanical behavior of these materials was studied. The quasi-static compression experiment and the dynamic compression experiment were carried out on the samples using the in situ micro-compression testing machine and the Split Hopkinson bar (SHPB) experimental equipment. The stress–strain curves of these materials at different strain rates were obtained, and the energy absorption characteristic of materials with two different levels were analyzed. This article reveals that the collapse strength and energy absorption properties of the materials are related to the hierarchical level of honeycomb. Multi-level hierarchical honeycomb (MHH) has higher collapse strength and better energy absorption properties than single-level hierarchical honeycomb (SHH). It turned out that increasing the hierarchical level of honeycomb could improve the mechanical properties of the materials. In the future development of products, the mechanical properties of hierarchical material by 3D printing can be further optimized through changing the level of the fractal structure.

scholarly journals Compressive Behavior of Aluminum Microfibers Reinforced Semi-Rigid Polyurethane Foams

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1298 ◽  
Author(s):  
Emanoil Linul ◽  
Cristina Vălean ◽  
Petrică-Andrei Linul
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Energy Absorption ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Polyurethane Foams ◽  
Compression Tests ◽  
Compressive Behavior ◽  
Static Compression ◽  
Pu Foams

Unreinforced and reinforced semi-rigid polyurethane (PU) foams were prepared and their compressive behavior was investigated. Aluminum microfibers (AMs) were added to the formulations to investigate their effect on mechanical properties and crush performances of closed-cell semi-rigid PU foams. Physical and mechanical properties of foams, including foam density, quasi-elastic gradient, compressive strength, densification strain, and energy absorption capability, were determined. The quasi-static compression tests were carried out at room temperature on cubic samples with a loading speed of 10 mm/min. Experimental results showed that the elastic properties and compressive strengths of reinforced semi-rigid PU foams were increased by addition of AMs into the foams. This increase in properties (61.81%-compressive strength and 71.29%-energy absorption) was obtained by adding up to 1.5% (of the foam liquid mass) aluminum microfibers. Above this upper limit of 1.5% AMs (e.g., 2% AMs), the compressive behavior changes and the energy absorption increases only by 12.68%; while the strength properties decreases by about 14.58% compared to unreinforced semi-rigid PU foam. The energy absorption performances of AMs reinforced semi-rigid PU foams were also found to be dependent on the percentage of microfiber in the same manner as the elastic and strength properties.

scholarly journals Effects of Modified Al2O3-Decorated Ionic Liquid on the Mechanical Properties and Impact Resistance of a Polyurethane Elastomer

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4712
Author(s):  
Fan Hu ◽  
Jun Gao ◽  
Biao Zhang ◽  
Fugang Qi ◽  
Nie Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Energy Absorption ◽  
Split Hopkinson Pressure Bar ◽  
Testing Machine ◽  
Impact Resistance ◽  
Compressive Yield Strength ◽  
Polyurethane Elastomer ◽  
Dynamic Impact ◽  
Static Compression

In this work, a new composite material with excellent dynamic impact resistance and outstanding quasi-static mechanical properties was synthesized. The composite material is composed of a polyurethane elastomer and a novel nano-polymer. The nano-polymer was composed of silane coupling agent-modified alumina microspheres and functionalized ionic liquids by double bond polymerization. The universal testing machine and split Hopkinson pressure bar were used to characterize the compression behavior, strength and energy absorption of the composite materials under static and dynamic conditions. Additionally, the comprehensive mechanical properties of polyurethane elastomer with different nano-polymer loadings (0.5–2.5 wt.%) were studied. The results show that whether it was static compression or dynamic impact, the polyurethane elastomer with 1% nano-polymer had the best performance. For the composite material with the best properties, its compressive yield strength under the static compression was about 61.13% higher than that of the pure polyurethane elastomer, and its energy absorption of dynamic impacts was also increased by about 15.53%. Moreover, the shape memory effect was very good (shape recovery is approximately 95%), and the microscopic damage degree was relatively small. This shows that the composite material with the best properties can withstand high compression loads and high-speed impacts. The developed composite material is a promising one for materials science and engineering, especially for protection against compression and impacts.

Evaluation of energy absorption capabilities and mechanical properties in FDM printed PLA TPMS structures

2021 ◽  
pp. 095440622110395
Author(s):  
Rakesh Sankineni ◽  
Y Ravi Kumar
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Advanced Technology ◽  
Morphological Properties ◽  
Cellular Structures ◽  
Poly Lactic Acid ◽  
Static Compression ◽  
Failure Patterns ◽  
Fused Deposition ◽  
The Impact

Additive manufacturing is an advanced technology used to fabricate complex geometries with unique properties like cellular structures which accommodate repeated unit cells located in the x, y and z direction. These structures can be used as infill patterns due to their self-supporting structure. Among the cellular structures, Triply Periodic Minimal Surface (TPMS) structures such as Gyroid, Diamond and Schwarz Primitive (SchwarzP) structures can be tailored to produce complex structures for various applications like tissue engineering scaffolds and replace the conventional polymeric foams. TPMS structures are designed and manufactured by using the Fused Deposition Modelling (FDM) technique using Poly-Lactic Acid (PLA) as material. Among TPMS structures, Gyroid is having a unique property like structurally symmetric which design was modified to enhance the mechanical properties. The modified Gyroid or deformed Gyroid undergone a quasi-static compression test and compare the results with Diamond and SchwarzP structures. Porosity and permeability coefficients are evaluated and an optical microscope is used to verify the fabricated components. As well as, Failure patterns of the structures were evaluated and energy absorption capabilities determined. The main objective of this paper is to evaluate the impact of design and porosity on the mechanical and morphological properties of TPMS structures. In conclusion, the deformed Gyroid has more energy absorption capability up to the 11.6% strain than other TPMS structures. After 11.6% of strain, SchwarzP structure dominates.

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