The Study on in Situ Asymmetric Bending Behavior of Structural Bamboo Materials Under Combined Tension-Bending Loads

2021 ◽  
Author(s):  
Jiucheng Zhao ◽  
Jie Wan ◽  
Changyi Liu ◽  
Zhuang Ren ◽  
Zhaoxin Wang ◽  
...  
2018 ◽  
Vol 124 (18) ◽  
pp. 185104 ◽  
Author(s):  
Z. Ren ◽  
T. W. Cornelius ◽  
C. Leclere ◽  
A. Davydok ◽  
J.-S. Micha ◽  
...  

2015 ◽  
Vol 1125 ◽  
pp. 94-99 ◽  
Author(s):  
Aldyandra Hami Seno ◽  
Eko Koswara ◽  
Hendri Syamsudin ◽  
Djarot Widagdo

This research was done to evaluate the bending behavior (load-deflection curve and failuremode) of sandwich structures using Tali Bamboo strips as sandwich skin material. Bending tests wereconducted on sandwich specimens with end grain balsa (3-point bending) and polypropylene (PP)honeycomb cores (4-point bending) to evaluate their bending behavior. From the test results,analytical and numerical models were developed to simulate the observed bending behavior. Themodels are able to simulate the pre-failure bending behavior and failure modes (core shear failure) ofthe specimens. It is also shown that for thin (length/thickness > 20) sandwiches the models are moreaccurate since shear effects are less prominent. With the obtained models a predictive comparison isdone between the PP and balsa cored specimens since the testing configuration for each type wasdifferent. The analysis results show that balsa cored specimens are able to withstand higher transversebending loads due to the higher shear strength of the balsa core. These prediction results are to beproven by specimen testing which is the subject of future research.


2011 ◽  
Vol 675-677 ◽  
pp. 685-688
Author(s):  
Jie Lu ◽  
Guang Ping Zou ◽  
Bao Jun Liu

Honeycomb sandwich structures are generally designed to carry flexural loads. However, mechanical properties can be influenced by accidental impacts, or service conditions. Thus a nondestructive detection testing is desired for them. In contrast to many conventional nondestructive evaluation (NDE) techniques, acoustic emission (AE) technique permits continuous damage inspection, classification and identification of failure modes in real time. In this work the fracture process of steel honeycomb sandwich beams has been investigated by in-situ AE technique. Pre-cracks were made both for L-direction and W-direction specimens subjected to three-points bending loads. Damage initiation sites were observed in the vicinity of the crack tip. A series of curves among the AE hits, AE amplitude, AE energy and loading time were obtained. Damage characteristics were discussed based on the above parameters. The results indicate AE characteristic parameters can reflect the damage and failure process of specimens. A good agreement was found between the experimental and analytical results.


1999 ◽  
Vol 604 ◽  
Author(s):  
J.Q Cheng ◽  
T.Y. Zhang ◽  
M.H. Zhao ◽  
C.F. Qian ◽  
S. W. R. Lee ◽  
...  

AbstractThis Paper investigates the bending behavior of piezoelectric laminates under combined mechanical and electrical loading. The laminate has a PZT - 5H ceramic core sandwiched by graphite/epoxy plates. Three-point bending tests and in-situ acoustic emission measurements were conducted on the PZT-5H laminates preloaded by an applied electric field. The results show that the PZT-5H core fractures first and then delaminaton occurs along the tensile stressed interface between the PZT ceremic and the graphite/epoxy layer. Finite element analysis was performed to analyze stresses in the sandwich structure under combined mechanical and electrical loading. Consequently, the bending strength of the PZT core was evaluated from the experiment data. The electric field, either positive or negative, reduces the fracture strength of the pzt core.


Author(s):  
Chongyao Zhou ◽  
Naiquan Ye ◽  
Svein Sævik

The service life of a flexible riser is often dominated by the metallic layers under cyclic bending loads, particularly the tensile armor layers. The effect of the anti-wear tapes is normally omitted during cross section modelling, where a plane-remain-plane assumption is usually used for stick condition. Significant differences have been observed between numerical analysis assuming plane surfaces remain plane and laboratory measurements studying the bending moment versus curvature for a flexible riser which has anti-wear tapes between the two tensile armor layers. A new shear interaction algorithm has been developed in the numerical model to improve the modeling of the anti-wear tapes by taking the thickness and shear modulus of the anti-wear material into account. The impact of these parameters on the bending behavior of the flexible riser is demonstrated by comparing the numerical analysis results with the laboratory measurements.


2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Tokushi Kizuka ◽  
Kun'ichi Miyazawa ◽  
Takayuki Tokumine

Single-crystal nanowhiskers (NWs) composed of fullerene C70molecules were synthesized by the liquid-liquid interfacial precipitation method that usedm-xylene as a saturated solution of C70molecules. Bending behavior of the individual NWs was observed byin situtransmission electron microscopy equipped with nanonewton force measurements using an optical deflection method. The Young’s modulus of the NWs was estimated to be 0.3–1.9 GPa, which was 2–7% of the moduli of fullerene NWs with similar diameters synthesized using other solvents, that is, toluene and pyridine. The influence of the solvent used in the precipitation method on Young’s modulus is discussed.


2017 ◽  
Vol 13 ◽  
pp. 378-385 ◽  
Author(s):  
Yali Dong ◽  
Xiaolei Shi ◽  
Zhongya Zhang ◽  
Bing Pan

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.


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