A study on mechanical properties after bonded repair of sandwich composite materials

2020 ◽  
Vol 34 (07n09) ◽  
pp. 2040033 ◽  
Author(s):  
Sunghoon Kim ◽  
Jongrok Ha ◽  
Seongwon Yoon ◽  
Myunghyun Kim
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Composite Materials ◽  
Recovery Rate ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Sandwich Composite ◽  
Bonded Repair ◽  
Patch Repairs ◽  
The Difference

In this paper, an experimental study was conducted to determine the efficiency of repair methods for sandwich composites used as hull materials in leisure ships. The method was applied to external, scarf, and step patch repairs using an epoxy bond. The load was described in terms of the hogging and sagging moments applied to the hull by waves. Static and fatigue tests were performed to derive the recovery rate of repaired specimens. The experimental results indicated that the recovery rate of specimens with the scarf patch was the highest at 91.80% when the hogging moment was applied. However, the difference in the recovery rate between hogging and sagging moments was the lowest for specimens with the step patch, and the recovery rate was high at 89.96% and 85.15%, respectively.

Effects of ionic liquid types on the tribological, mechanical, and thermal properties of ionic liquid modified graphene/polyimide shape memory composites

2021 ◽  
pp. 095400832199676
Author(s):  
Yuting Ouyang ◽  
Qiu Zhang ◽  
Xiukun Liu ◽  
Ruan Hong ◽  
Xu Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ionic Liquid ◽  
Composite Materials ◽  
Shape Memory ◽  
Recovery Rate ◽  
Shape Recovery ◽  
Graphene Nanosheets ◽  
Mechanical And Thermal Properties ◽  
Thermal And Mechanical Properties ◽  
Modified Graphene

Different ionic liquid modified graphene nanosheets (IG) were induced into polyimide (PI) to improve the tribological, thermal, and mechanical properties of shape memory IG/PI composites. The results demonstrated that when using 1-aminoethyl-3-methylimidazole bromide to modify graphene nanosheets (IG-1), the laser-driven shape recovery rate of IG-1/PI composites (IGPI-1) reached 73.02%, which was 49.36% higher than that of pure PI. In addition, the IGPI-1 composite materials reached the maximum shape recovery rate within 15 s. Additionally, under dry sliding, the addition of IG can significantly improve the tribological properties of composite materials. IGPI-1 exhibited the best self-lubricating properties. Compared with pure PI, the friction coefficient (0.19) and wear rate (2.62 × 10–5) mm3/Nm) were reduced by 44.1% and 24.2%, respectively, and the T10% of IGPI-1 increased by 32.2°C. The Tg of IGPI-1 reached 256.5°C, which was 8.4°C higher than that of pure PI. In addition, the tensile strength and modulus of IGPI-1 reached 82.3 MPa and 1.18 GPa, which were significantly increased by 33.6% and 29.8%, respectively, compared with pure PI. We hope that this work will be helpful for the preparation of shape memory materials with excellent tribological, thermal, and mechanical properties.

scholarly journals Experimental Study of Vibrational Acceleration Spread and Comparison Using Three Citrus Canopy Shaker Shaking Tines

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Tian-Hu Liu ◽  
Reza Ehsani ◽  
Arash Toudeshki ◽  
Xiang-Jun Zou ◽  
Hong-Jun Wang
Keyword(s):  
Experimental Study ◽  
Experimental Results ◽  
Average Decrease ◽  
Vibrational Acceleration ◽  
The Difference ◽  
Canopy Shaker

The goal of this article is to experimentally study how the vibrational acceleration spreads along the branch shaken by PVC tine, steel tine, and nylon tine for citrus canopy shaking harvesting and to compare the difference. PVC tine and steel tine have potential to be used as shaking rod for citrus canopy shaking harvesting. Nylon tine is a commonly used shaking rod. A tractor-mounted canopy shaker was developed to do the trial. The shaking frequency was set at 2.5 and 5 Hz. Experimental results showed that the vibrational acceleration at the shaking spot is not the highest. Spreading from shaking spot to the stem, it increases evidently. When spreading from stems of the outside subbranch to stems of the nearest inside subbranch, its average decrease percentage is 42%. The overall vibrational acceleration of shaking at 5 Hz is 1.85 times as high as shaking at 2.5 Hz. The overall vibrational acceleration exerted by straight PVC tine and steel tine is 1.77 and 1.97 times as high as that exerted by straight nylon tine, respectively. It is indicated that replacing nylon tine with steel tine or PVC tine helps remove the fruits inside the canopy. Replacing with steel tine is more effective than with PVC tine.

Experimental Study on the Mechanical Properties of Two Sandwich Structure Composite Materials

2013 ◽  
Vol 561 ◽  
pp. 466-471
Author(s):  
Chuan Sheng Wang ◽  
Qing Kun Liu
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Tensile Strength ◽  
Composite Materials ◽  
Sandwich Structure ◽  
National Standards ◽  
Honeycomb Sandwich ◽  
Pros And Cons ◽  
Nomex Honeycomb ◽  
Honeycomb Sandwich Structure

According to the relevant national standards, this paper produced Corecell ™ G foam sandwich structure and Nomex honeycomb sandwich structure composite materials specimens. These two materials were carried out tensile, compression, bending and shear experiment. Analyzing and comparing the pros and cons of the two materials in the mechanical properties of tensile strength, compressive strength, shear strength, flexural strength.

Experimental Study on Behaviour of Rc T-Beam Strengthened with Jute Fiber Laminates - A Review

2019 ◽  
Vol 1 (6) ◽  
pp. 503-508
Author(s):  
Tharunkumar N ◽  
Anand G
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Tensile Properties ◽  
Natural Fiber ◽  
Low Cost ◽  
Shear Capacity ◽  
Experimental Results ◽  
Jute Fiber ◽  
Structural Behaviour ◽  
Synthetic Fibers

The present investigation addresses the external strengthening of reinforced concrete (RC) T-beams using jute fiber laminates. An experimental study is mainly carried out to study the change in structural behaviour of RC T-beams using externally wrapped jute fiber laminates, to enhance the shear and flexural capacity of the beams. The effect of pattern and orientation of the strengthening fabric on the shear capacity of the strengthened beams will be examined. RC T-beams with minimum shear reinforcement is designed and then external confinement using jute fiber laminates is carried out using epoxy resin. The layer confinement is executed to study and analyze the behaviour of confined beams with respect to control beam. Experimental results showing the advantage of beam strengthened using the various lay-ups of jute fiber are to be discussed. For all developed composites, experimental results revealed that the tensile properties of the developed composites are strongly dependent on the tensile strength of jute fiber and that the tensile properties of jute fiber are very much defect sensitive. Jute as a natural fiber is eco-friendly, low cost, versatile in textile fields and has moderate mechanical properties, which replaced several synthetic fibers in development of many composite materials. However, the hydrophilic nature of the jute fiber affects the mechanical properties of the developed composites. As a result to arrest crack and improve the strength of beam.

Experimental Study of Viscoelastic Dampers under Large Deformation

2012 ◽  
Vol 166-169 ◽  
pp. 2226-2233 ◽  
Author(s):  
Gang Zhao ◽  
Peng Pan ◽  
Jia Ru Qian ◽  
Jin Song Lin
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Energy Dissipation ◽  
Low Cycle Fatigue ◽  
Loss Modulus ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Small Displacement ◽  
Loading Frequency ◽  
Cycle Fatigue

The paper presents an experimental study on a new type viscoelastic damper, which is expected to have better energy dissipation capability. Tests on the dampers’ mechanical properties, including shear storage modulus, shear loss modulus, and loss factor, were conducted using reduced scale specimens, and took strain amplitude, loading frequency and ambient temperature as test parameters. Aging tests, low cycle and high cycle fatigue tests were also conducted. Particularly, the low cycle fatigue behavior under a strain of 300% and the basic mechanical behavior under strains of 300%-420% were investigated. Test results suggest that the dependency of the mechanical properties on frequency and temperature is small, the energy dissipation capacity is stable for both large and small displacement, and the damper reaches a strain of 420% without failure.

Experimental Study of Relations between Synchronous Rotor Speed and Mixing Process

2012 ◽  
Vol 501 ◽  
pp. 243-246
Author(s):  
Xian Kui Zeng ◽  
Shuai An ◽  
De Wei Zhang ◽  
Dong Wang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Temperature Increase ◽  
Physical And Mechanical Properties ◽  
Experimental Results ◽  
Mixing Process ◽  
Rotor Speed ◽  
Unit Consumption ◽  
Internal Mixer ◽  
Rotor Structure

Rotor speed is one of the most important technical characteristics of the internal mixer. The effects of rotor speed on mixing process have been studied. In the experiments, three types of synchronous rotors which were two-wing synchronous rotor, four-wing synchronous rotor and six-wing synchronous rotor were used. The experimental results indicated that there was a proper speed of different rotor structure for mixing process. And along with the increase of rotor speed, the maximum power, the unit consumption of energy and discharging temperature increase, while the physical and mechanical properties of mixed rubber got a better value.

Experimental Study on Ultrasonic Milling Acoustic System

2010 ◽  
Vol 42 ◽  
pp. 355-358 ◽  
Author(s):  
Zhang Dong Li ◽  
Bo Zhao ◽  
Jun Jin Ma
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Composite Materials ◽  
Resonant Frequency ◽  
Resonance Frequency ◽  
End Milling ◽  
Oscillation Amplitude ◽  
Materials Processing ◽  
Acoustic System ◽  
Ultrasonic Milling

Composite materials have good mechanical properties. In order to solve the difficult process of composite materials, this paper proposes to use a method of ultrasonic milling on the composite materials processing, we mainly studies the effect of the length of the arbor, arbor diameter and arbor end milling platform on the acoustic resonant frequency, amplitude, and anti-resonance frequency. With the decreased in the length of the tool bar, tool bar's resonant frequency increased，and the oscillation amplitude also obviously increased. In the vicinity of 35 KHz amplitude of vibration are largest. Along with tool bar diameter's increasing, the resonant frequency is increases gradually. Milling platform has little effect on the resonant frequency and amplitude.

scholarly journals Case Study of Chosen Sandwich-Structured Composite Materials for Means of Transport

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 750
Author(s):  
Pavel Koštial ◽  
Zora Koštialová Jančíková ◽  
Ivan Ružiak ◽  
Milada Gajtanska
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Fuel Economy ◽  
Standard Test ◽  
Impact Testing ◽  
Sandwich Composite ◽  
Surface Finishes ◽  
Bending Behavior ◽  
State Of Affairs

Modern means of transport increasingly utilize sandwich constructions. Among other things, the reasons for such state of affairs include the reduced weight of means of transport, and through this, better fuel economy as well as price. This work is dedicated to a systematic experimental study of the influence of various materials and sandwich designs on their mechanical properties. In the framework of experiments, sandwich-structured composites were exposed to two types of stressing: static as well as impact stressing. The testing of prepared samples was performed according to ASTM C-393 Standard, dealing specifically with the bending behavior of sandwich composite constructions and impact testing under the scope of ISO 6603-2 Standard test. In this article we deal with static and impact testing of the eight types of core materials, two types of coatings, two types of surface finishes, and two types of resins with a special emphasis on their use in constructions of some exterior or interior components of transport means.

Fatigue analysis of a composite ring: Experimental and theoretical investigations

2020 ◽  
Vol 54 (26) ◽  
pp. 4011-4024 ◽  
Author(s):  
Roham Rafiee ◽  
Faramarz Abbasi ◽  
Sattar Maleki
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Damage Mechanics ◽  
Fatigue Testing ◽  
Continuum Damage Mechanics ◽  
Fatigue Loading ◽  
Fatigue Analysis ◽  
Fatigue Tests ◽  
Composite Ring ◽  
Degradation Of Mechanical Properties

The behavior of composite rings against fatigue loading is analyzed. Experimental study is performed to evaluate the ultimate hoop strength of the composite ring as a requirement before fatigue testing. Then, fatigue tests are performed at three different load levels. Afterward, progressive damage modeling in the context of continuum damage mechanics is utilized to theoretically estimate fatigue lifetimes of the investigated rings. The modeling consists of three parts as stress analysis, damage estimation and degradation of mechanical properties. It is mainly aimed to reduce the required runtime for the accomplishment of fatigue analysis while the accuracy is at least compromised. Therefore, a manual technique is adapted for extracting stress components on the ring. Degradation of mechanical properties takes place either through gradual procedure or sets of sudden laws. The gradual degradation of mechanical properties is performed based on the damage progression as a function of cycle numbers and stress state. Sudden degradation is done after occurrence of failure. After reduction of mechanical properties, the model is updated and whole procedure repeats till the whole layers fail. Finally, the results of fatigue modeling are compared with performed experimental study and a very good agreement is observed.

Experimental Study of Screw Speed Effects on Quality of Short Fiber-Rubber Composite Material

2011 ◽  
Vol 221 ◽  
pp. 369-372 ◽  
Author(s):  
Chuan Sheng Wang ◽  
De Wei Zhang ◽  
Hui Guang Bian ◽  
Xiao Bo Wang ◽  
Lei Guo
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Composite Material ◽  
Physical And Mechanical Properties ◽  
Short Fiber ◽  
Experimental Results ◽  
Short Fibers ◽  
Screw Speed ◽  
Rubber Composite

During the extruding process of short fiber-rubber composite material, screw speed is an important factor which influences the orientation of short fibers, as well as the physical and mechanical properties of short fiber-rubber composite material. The effects of different screw speeds on physical and mechanical properties of short fiber-rubber composite material have been studied by experimental study. In the experiments, the screw speeds were 10rpm, 15rpm, 20rpm, 25rpm and 30rpm respectively. The experimental results indicated that when the screw speed was 15rpm, the physical and mechanical properties of short fiber-rubber composite material are better.

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