scholarly journals Wash Analyses of Flexible and Wearable Printed Circuits for E-Textiles and Their Prediction of Damages

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1362
Author(s):  
Shahood uz Zaman ◽  
Xuyuan Tao ◽  
Cédric Cochrane ◽  
Vladan Koncar

The development of specific user-based wearable smart textiles is gaining interest. The reliability and washability of e-textiles, especially electronic-based components of e-textiles, are under particular investigation nowadays. This is because e-textiles cannot be washed like normal textile products and washing electronic products is not common practice in our daily life. To adopt the e-textile products in our daily life, new standards, based on product usage, should be developed especially for flexibility and washability. The wearable motherboards are the main component for e-textile systems. They should be washing reliable and flexible for better adoption in the system. In this manuscript, flexible wearable PCBs were prepared with different conductive track widths and protected with silicone coatings. The samples were washed for 50 washing cycles in the household washing machine, and provoked damages were investigated. The PCBs were also investigated for bending tests (simulating mechanical stresses in the washing machine), and resultant damages were discussed and co-related with washing damages. The bending test was performed by bending the FPCBs at 90° over the circular rod and under the known hanging load.

Author(s):  
Ho-Sang Shin ◽  
Jin-Ki Hong ◽  
Koo-Kab Chung ◽  
Hae-Dong Chung ◽  
Gwang-Yil Kim ◽  
...  

As the design life of new nuclear power plant increases, the austenitic stainless cladding integrity of reactor vessel becomes one of the new concerns. Since 1970’s, there have been some specific recommendations on delta ferrite content of austenitic cladding of reactor vessels and welds. It has been known that the delta ferrite is beneficial for reducing micro-fissure in welds, though the high delta ferrite content increases the probability of embrittlment of welds. In this study, the mechanical and microstructural properties of austenitic weld metals with the limit values of the recommended range (5 ∼ 18 FN) of the delta ferrite control on low alloy steels were characterized by using bending test and scanning electron microscopy. The base metal was ASME Code Sec. II specification SA 508 Gr. 3 Cl. 1 plate and weld materials were EQ308L and EQ309L strips. Four kinds of cladding were deposited with submerged arc welding process on SA508 cl.3 plates. The bending tests were performed through ASME code Sec. IX and the microstructure of fractured surfaces was analyzed by scanning electron microscopy (SEM). In bending tests, there were no fractures except the highest delta ferrite content specimens (28FN). From the SEM observation of fractured surfaces, cracks initiated from the interface between austenite and ferrites phases in the cladding layer and propagated through the continuous interfaces between two phases. For specimens without continuous interfaces of two phases, though the cracks were observed in the interface of phases, the propagation of cracks was not observed. From the test results, continuous interfaces between austenite matrix and ferrite phase provide the path for crack propagation. And the delta ferrite content affects the integrity of cladding of reactor vessel.


Author(s):  
Hisakazu Tajika ◽  
Takahiro Sakimoto ◽  
Tsunehisa Handa ◽  
Rinsei Ikeda ◽  
Joe Kondo

Recently high grade pipeline project have been planned in hostile environment like landslide in mountain area, liquefaction in reclaimed land or the frost heave in Polar Regions. Geohazards bring large scale ground deformation and effect on the varied pipeline to cause large deformation. Therefore, strain capacity is important for the pipeline and strain based design is also needed to keep gas transportation project in safe. High grade steel pipe for linepipe tends to have higher yield to tensile (Y/T) ratio and it has been investigated that the lower Y/T ratio of the material improves strain capacity in buckling and tensile limit state. In onshore pipeline project, pipe usually transported in 12 or 18m each and jointed in the field. Girth weld (GW) is indispensable so strength matching of girth weld towards pipe body is important. In this study strain capacity of Grade X70 high strain pipes with size of 36″ OD and 23mm WT was investigated with two types of experiments, which are full scale pipe bending tests and curved wide plate tests. The length of the specimen of full scale bending tests were approximately 8m and girth weld was made in the middle of joint length. A fixed internal pressure was applied during the bending test. Actual pipe situation in work was simulated and both circumferential and longitudinal stress occurred in this test. Test pipes were cut and welded, GTAW in first two layer and then finished by GMAW. In one pipe, YS-TS over-matching girth weld (OVM) joint was prepared considering the pipe body grade. For the other pipe, intentionally under-matching girth weld (UDM) joint was prepared. After the girth welding, elliptical EDM notch were installed in the GW HAZ as simulated weld defect. In both pipe bending tests, the buckling occurred in the pipe body at approximately 300mm apart from the GW and after that, deformation concentrated to buckling wrinkle. Test pipe breaking locations were different in the two tests. In OVM, tensile rupture occurred in pipe body on the backside of buckling wrinkle. In UDM, tensile rupture occurred from notch in the HAZ. In CWP test, breaking location was the HAZ notch. There were significant differences in CTOD growth in HAZ notch in these tests.


2006 ◽  
Vol 309-311 ◽  
pp. 1191-1194
Author(s):  
Shuichi Wakayama ◽  
Teppei Kawakami ◽  
Junji Ikeda

Microfracture process during bending tests of alumina ceramics used for artificial joints was evaluated by acoustic emission (AE) technique. Four-point bending tests were carried out in air, refined water, physiological saline and simulated body fluid. AE behavior during bending test inhibited the rapid increasing point of AE events and energy prior to the final unstable fracture. It was understood that the bending stress at the increasing point corresponds to the critical stress for maincrack formation. The critical stress was affected by water in environments more strongly than fracture strength. Consequently, it was suggested that the characterization of maincrack formation is essential for the long-term reliability assessment of load-bearing bioceramics.


Author(s):  
Tomáš Binar ◽  
Jiří Švarc ◽  
Petr Dostál ◽  
Michal Šustr ◽  
Jan Tippner

This article deals with the spread of corrosion in material at different exposure times, and its effect on the measured brittle fracture and notch impact strength under different temperature conditions. To assess the degradational effect of corrosion on the material characteristics represented by the measured impact strength, we conducted a fractographic analysis of fracture surfaces, the aim of which was to evaluate the spread of corrosion in the material. In the first part of the experiment, two corrosion tests are simulated with a duration time of 432 and 648 hours, to compare the degradation effect of corrosion on the notch impact strength, depending on the duration of the corrosion tests. The following part shows the results of the impact bending test, where the experiment was conducted in an area of reduced and increased temperatures. The final part summarizes the results of the fractographic analysis of sample fracture surfaces from the impact bending tests. Based on the measured the length of the corrosion cracks, we analyzed the sample at the notch and from the material surface after the impact bending test.


Author(s):  
L. A. Ryabicheva ◽  
R. E. Velikotskii

Meeting the high requirements to the whole complex of mechanical characteristics is the main criteria of reliability and long service life of shipbuilding steels. To determine them it is necessary to apply modern methodologies of metal science analysis. Revelation of regularity of influence of alloying, carbon equivalent, microstructure and production technology on results of bending test of low-alloyed grades А32, D32, Е32 shipbuilding steels was the purpose of the study. Production of steel, rolling, thermal treatment, mechanical tests and metal science studies of the low-alloyed shipbuilding steels was made in Alchevsk steel-works. A quantity estimation of the D32 grade sheets microstructure was made as a result of studies, having both satisfactory and not satisfactory results of bending tests. It was determined, that stitch oxides have the most negative influence on the results of bending tests for both hot-rolled and normalized sheets. Sheets with not satisfactory results of bending tests differ from those, which passed the tests by higher value of streakiness points, particular of perlite, and in normalized condition – by higher value of Widmanstatten pattern. Sheets, which did not passed the tests, have yield strength by 5–25 MPa and tensile strength by 14–39 MPa higher, while the tensile strength was by 1.2–4.8% lower. For stable yield in bending tests within 98–100% it is necessary the tensile strength level to be not less than 30%. It is reasonably all the sheets of 10–20 mm thick out of heats with carbon equivalent higher 0.54% to subject compulsory normalization. Further increase of the sheets product yield can be achieved by decreasing of phosphor mass share and increasing of general steel purity, first of all, by decreasing of oxide inclusions


Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5190 ◽  
Author(s):  
Miriam Alvarado ◽  
Silvia De La Flor ◽  
Eduard Llobet ◽  
Alfonso Romero ◽  
José Luis Ramírez

Many sensors are developed over flexible substrates to be used as wearables, which does not guarantee that they will actually withstand being bent. This work evaluates the gas sensing performance of metal oxide devices of three different types, before and after having undergone automated, repetitive bending tests. These tests were aimed at demonstrating that the fabricated sensors were actually flexible, which cannot be taken for granted beforehand. The active layer in these sensors consisted of WO3 nanowires (NWs) grown directly over a Kapton foil by means of the aerosol-assisted chemical vapor deposition. Their response to different H2 concentrations was measured at first. Then, they were cyclically bent, and finally, their response to H2 was measured again. Sensors based on pristine WO3-NWs over Ag electrodes and on Pd-decorated NWs over Au electrodes maintained their performance after having been bent. Ag electrodes covered with Pd-decorated NWs became fragile and lost their usefulness. To summarize, two different types of truly flexible metal oxide gas sensor were fabricated, whereas a third one was not flexible, despite being grown over a flexible substrate following the same method. Finally, we recommend that one standard bending test procedure should be established to clearly determine the flexibility of a sensor considering its intended application.


2019 ◽  
Vol 292 ◽  
pp. 9-14 ◽  
Author(s):  
Oldrich Sucharda ◽  
Vlastimil Bilek

Concrete is typical composite material and its properties can be very variable. Material properties are also influenced with the technology of processing, manufacturing and treatment after concreting. Reinforcement in form of fibers is often added for improving tensile strength. This paper deals with specific testing of fibre concrete. Test results of series of specimens are presented for selected transport concrete composition, which is reinforced with amount of fibers 25, 50, 75 kg / m3. Fibers were added directly into the into the concrete mixer in the factory. Each series includes more than 25 test samples. The tests include the compressive strength of a cube and cylindrical, testing of modulus of elasticity, and the split tensile strength in the direction perpendicular to and parallel to the filling. Within the research project also a few types of bending tests were performed. Four variants of bending test that vary in span of 500 or 600 mm, samples with and without a notch, and in a three- / four-point configuration. As a summary, broader evaluation and functional dependencies are derived.


2018 ◽  
Vol 7 (3.34) ◽  
pp. 133
Author(s):  
Mr. S.K.Manigandan ◽  
Mrs. R.Latha ◽  
Mr. S.MohamedAsik ◽  
J Velmurugan ◽  
D Ramya

In our these days life on-line purchase associated e-commerce website   has changing into   an mandatory  things   in  our  daily  life vogue  since,  it conjointly  have  some  major  issue  like  purchasing  a product  with  unhappy  mode  and   lack  of data  in product  usage.  therefore as to  overcome  these  drawback we  have  a tendency to   have new entranceway referred to as   live chat  in on-line looking. We have a tendency to  will  offer    this  live   chat  in  most   safest  method  exploitation   the   end  to  finish cryptography  methodology , most  of  the  looking can  have  a   live  chat however  they Weren’t   provided   a cut price options and most e-commerce website   don’t   have Chat choices.  We have a tendency to will even enable the client and producer to Share their thoughts.  


Author(s):  
Mahbub Ahmed ◽  
Md. R. Islam ◽  
Justin Vanhoose ◽  
Lionel Hewavitharana ◽  
Aaron Stanich ◽  
...  

3D printing technology has become more affordable than ever before. Today 3D printers are not only used for making prototypes but are also being used to make good quality 3D parts for different purposes. A wide variety of filament materials are used in the market. Finding bending stiffness of different plastic filaments is the particular interest in the current study. The purpose of the project is to investigate the bending stiffness of different 3D printed beam samples. A series of samples for performing bending tests were designed using a solid modeling tool. These samples were printed with four different plastic filaments on a 3D printer in the engineering Lab of Southern Arkansas University. The samples were tested for flexural stiffness (bending) using a materials testing system. A popular 3-point bending test was conducted for this purpose. The force vs. deflection data was obtained to obtain the flexural stiffness of the beam samples. The results were discussed in detail in the result section of this paper.


2015 ◽  
Vol 1083 ◽  
pp. 90-96 ◽  
Author(s):  
Ana Almerich-Chulia ◽  
E. Fenollosa ◽  
I. Cabrera

In order to obtain GFRP reinforcement bars it is necessary to undertake tests regulated code which require important mechanical tools. This paper presents a method which allows for determining GFRP rebars tensile strength value from their flexural strength value which has been obtained with a simple, inexpensive and reliable test. This method results will be verified by applying it to values obtained in a series of bending tests and comparing these results with values obtained in tensile tests. Values concordance for small diameter GFRP rebars is very good.


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