scholarly journals Bending Setups for Reliability Investigation of Flexible Electronics

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 78
Author(s):  
Rafat Saleh ◽  
Maximilian Barth ◽  
Wolfgang Eberhardt ◽  
André Zimmermann
Keyword(s):  
Flexible Electronics ◽  
Test Methods ◽  
Bending Test ◽  
Flexible Systems ◽  
Flexible Displays ◽  
Dynamic Bending

Flexible electronics is a rapidly growing technology for a multitude of applications. Wearables and flexible displays are some application examples. Various technologies and processes are used to produce flexible electronics. An important aspect to be considered when developing these systems is their reliability, especially with regard to repeated bending. In this paper, the frequently used methods for investigating the bending reliability of flexible electronics are presented. This is done to provide an overview of the types of tests that can be performed to investigate the bending reliability. Furthermore, it is shown which devices are developed and optimized to gain more knowledge about the behavior of flexible systems under bending. Both static and dynamic bending test methods are presented.

scholarly journals Influence of Bitumen Type and Asphalt Mixture Composition on Low-Temperature Strength Properties According to Various Test Methods

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2118 ◽  
Author(s):  
Marek Pszczola ◽  
Cezary Szydlowski
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Cooling Rate ◽  
Strength Properties ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Mixture Composition ◽  
Tension Stress ◽  
Strength Reserve

In regions with low-temperatures, action transverse cracks can appear in asphalt pavements as a result of thermal stresses that exceed the fracture strength of materials used in asphalt layers. To better understand thermal cracking phenomenon, strength properties of different asphalt mixtures were investigated. Four test methods were used to assess the influence of bitumen type and mixture composition on tensile strength properties of asphalt mixtures: tensile strength was measured using the thermal stress restrained specimen test (TSRST) and the uniaxial tension stress test (UTST), flexural strength was measured using the bending beam test (BBT), and fracture toughness was measured using the semi-circular bending test (SCB). The strength reserve behavior of tested asphalt mixtures was assessed as well. The influence of cooling rate on the strength reserve was investigated and correlations between results from different test methods were also analyzed and discussed. It was observed that the type of bitumen was a factor of crucial importance to low-temperature properties of the tested asphalt concretes. This conclusion was valid for all test methods that were used. It was also observed that the level of cooling rate influenced the strength reserve and, in consequence, resistance to low-temperature cracking. It was concluded that reasonably good correlations were observed between strength results for the UTST, BBT, and SCB test methods.

scholarly journals Artificial Frozen Soil Bending Test and Bending Property

2020 ◽  
Vol 165 ◽  
pp. 03028
Author(s):  
Liu Tao ◽  
Huang Zhi ◽  
Zheng Zhigang ◽  
Hong Shaoyou ◽  
Li Jia ◽  
...  
Keyword(s):  
Earth Pressure ◽  
Bending Moment ◽  
Freezing Temperature ◽  
Test Methods ◽  
Frozen Soil ◽  
Bending Test ◽  
Frozen Soils ◽  
Temporary Support ◽  
Artificial Freezing ◽  
Ground Method

Artificial freezing ground method has been widely used in tunnels, metro and other projects, in the connecting passage in metro, the artificial frozen soil wall, which is formed by artificial freezing method, is often used as temporary support. The artificial frozen soil wall is in the joint action of pressure and bending moment, for it takes the upper pressure and lateral earth pressure at same time, so there may be tensile stress in the profile, which may cause brittle failure. At present, some scholars have carried out researches on the tensile strength with different test methods, but they are insufficiency and have a certain difference in stress state between the specimen and the actual support structure. A bending test instrument was designed and manufacture, which satisfies the code’s requirements, and reduces the error caused by poor contact between the specimen and loading device. Bending test on artificially frozen soils was launched using this instrument, and the test on influence law of moisture content and freezing temperature on artificially frozen soils’ strength was also launched. The conclusions can provide a reference for design and construction.

scholarly journals Stiffness and Fatigue of Asphalt Mixtures for Pavement Construction

2018 ◽  
Vol 26 (2) ◽  
pp. 24-29 ◽  
Author(s):  
Juraj Šrámek
Keyword(s):  
Fatigue Life ◽  
Asphalt Mixture ◽  
Construction Materials ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Deformation Properties ◽  
Pavement Construction ◽  
And Control

AbstractThe quality of a road is affected by its correct design, the appropriate use of materials, the effects of the climate, and the technological discipline. The deformation properties and fatigue of asphalt layers are important for the design and assessment of semi-rigid and flexible pavements. The assessment of deformation properties is performed by means of a dynamic impact test and the fatigue life of a particular asphalt mixture. An evaluation of the fatigue life is based on decreases in resistance or increases in deformations in different binders and mixtures. The test methods for the design and control of pavement construction materials determine the basic conditions valid for flexible matter. The Two-Point Bending Test was used for determining the deformation characteristics and the fatigue of asphalt mixtures at the Department of Construction Management in Zilina.

East Asian Calligraphy Black Ink-Coated Paper as Flexible Conducting Electrode for Supercapacitor

2021 ◽  
Author(s):  
Ren-Jie Xie ◽  
I-Chun Cheng ◽  
Jian-Zhang Chen
Keyword(s):  
Flexible Electronics ◽  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
East Asian ◽  
Electrical Conductance ◽  
Angle Measurement ◽  
Bending Test ◽  
Coated Paper ◽  
Water Contact ◽  
X Ray

Abstract East Asian calligraphy black ink (hereafter called simply “black ink”) is used to fabricate flexible conducting chromatography paper electrode by a simple and low-cost method. The black ink-coated paper was characterized by scanning electron microscopy, surface profiler, water contact angle measurement, electrical resistance measurement, X-ray photoelectron spectroscopy, and X-ray diffraction. The hydrophilicity slightly decreased after black ink coating but still provided good adhesion to the follow-up reduced graphene oxide/polyaniline/chitosan slurry coating for fabricating supercapacitor electrodes. A 1000-cycle repeated bending test with a bending radius of 5 mm revealed good conductance retention. Instrumental analyses indicated that the carbon black in the black ink was the main contributor to the electrical conductance. The supercapacitor with black-ink-coated paper electrodes exhibited an areal specific capacitance of up to 179.08 mF/cm² and coulomb efficiency of 80%. This confirmed that the black-ink-coated paper electrode could be feasibly applied to a supercapacitor. This black-ink-coated paper can be easily fabricated in resource-limited settings, and it provides new possibilities for the use of paper-based electrodes in flexible electronics.

Evaluation of Bending Test Methods for Composite Materials

1985 ◽  
Vol 7 (1) ◽  
pp. 12 ◽  
Author(s):  
WW Feng ◽  
KL Reifsnider ◽  
GP Sendeckyj ◽  
TT Chiao ◽  
WS Johnson ◽  
...  
Keyword(s):  
Composite Materials ◽  
Test Methods ◽  
Bending Test

A New Type of Road Material Prepared from Coal Tar Pitch

2017 ◽  
Vol 20 ◽  
pp. 51-56
Author(s):  
Zhe Liu ◽  
Peng Fei Liu ◽  
Chong Liang Sun
Keyword(s):  
Coal Tar ◽  
Test Methods ◽  
Standard Test ◽  
Bending Test ◽  
Coal Tar Pitch ◽  
Temperature Property ◽  
Technical Standards ◽  
Before And After ◽  
New Type ◽  
Wheel Tracking

A new type of road material was made by modifying coal tar pitch with a kind of self-made compound modifier. According to technical standards “Standard Test Methods of Bitument and Bituminous Mixture for Highway Engineering” JTG E20-2011, the properties of modified coal-tar pitch (M-CTP) and its mixture were studied, the softening point, ductility and penetration of M-CTP were all up to standard. Moreover, the properties of M-CTP mixture were also investigated, the wheel tracking test showed the M-CTP mixture has a dynamic stability of 1511n/mm, which was higher than the requirement of ≥800n/mm. The beam bending test results indicated the low-temperature property of M-CTP mixture reach the standard of AH-70 mixture. The Freeze-thaw split test demonstated the water stability of M-CTP mixture meet the standard for using in asphalt pavement. In all, a new type of road material by modifying coal tar pitch was obtained and its properties meet the standard of AH-70. The additive amount of modifier was 15% and the optimum effect was attained. Moreover, the ultraviolet and visible spectrophotometer was used to test the content of benzopyrene (BaP) in CTP before and after modified by M. And the content decreased from 1.92% to 1.62%.

Nanopackaging for Component Assembly and Embedded Power in Flexible Electronics: Heterogeneous Component Integration for Flexible Systems

2018 ◽  
Vol 12 (4) ◽  
pp. 6-18 ◽  
Author(s):  
Ninad Shahane ◽  
P. Markondeya Raj ◽  
Chandrasekharan Nair ◽  
Vanessa Smet ◽  
Chintan Buch ◽  
...  
Keyword(s):  
Flexible Electronics ◽  
Flexible Systems ◽  
Component Integration ◽  
Embedded Power ◽  
Component Assembly

scholarly journals Characterization of Material Stiffness on Injection Moulded Microspecimens Using Different Test Methods

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Dietmar Drummer ◽  
Andreas Seefried ◽  
Steve Meister
Keyword(s):  
Standardized Test ◽  
Standard Specimen ◽  
Test Methods ◽  
Bending Test ◽  
Material Behaviour ◽  
Testing Methods ◽  
Material Stiffness ◽  
Internal Properties ◽  
Induced Changes

Injection moulding of polymer microparts can result in modified material behaviour due to process-induced changes in the internal properties. Thus, a transfer of the mechanical material properties in microparts, determined and valid on standardized test specimens, is only partially possible and should be verified on microtest specimens. This paper investigates both tensile and bending test methods for a suitable characterization of material stiffness in polymer microparts. For this purpose a down-scaled standard specimen is used and tested with different testing methods. The investigations reveal that the different testing methods result in comparable mechanical values. The effects of process-induced modified mechanical behaviour are observable in the investigated testing methods. Consequently, a microbending test is potentially a suitable method for characterizing material stiffness using microspecimens.

Sign in / Sign up

Export Citation Format

Share Document