scholarly journals Efficiently, accurately, intelligently dissecting bamboo: characteristic of vascular bundle in Phyllostachys

2021 ◽  
Author(s):  
Haocheng Xu ◽  
Ying Zhang ◽  
Jiajun Wang ◽  
Tuhua Zhong ◽  
Xinxin Ma ◽  
...  
Keyword(s):  
Cross Section ◽  
Radial Distribution ◽  
Vascular Bundle ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Width Ratio ◽  
Vascular Bundles ◽  
Fiber Volume ◽  
Detection Model ◽  
Gradient Change

AbstractA comprehensive understanding of vascular bundles is the key to elucidate the excellent intrinsic mechanical properties of bamboo. This research aims to investigate the gradient distribution of fiber volume fraction and the gradient changes in the shape of vascular bundles along the radial axis in Phyllostachys. We constructed a universal transfer-learning-based vascular bundle detection model with high precision of up to 96.97%, which can help to acquire the characteristics of vascular bundles quickly and accurately. The total number of vascular bundles, total fiber sheath area, the length, width and area of fiber sheath of individual vascular bundles within the entire cross-section were counted, and the results showed that these parameters had a strongly positive linear correlation with the outer circumference and wall thickness of bamboo culms, but the fiber volume fraction (around 25.5 %) and the length-to-width ratio of the vascular bundles (around 1.226) were relatively constant. Furthermore, we layered the cross section of bamboo according to the wall thickness finely and counted the characteristics of vascular bundle in each layer. The results showed that the radial distribution of fiber volume fraction decreased exponentially, the radial distribution of the length-to-width ratio of vascular bundle decreased quadratically, the radial distribution of the width of vascular bundle increased linearly. The trends of the gradient change in vascular bundle’s characteristics were found highly consistent among 29 bamboo species in Phyllostachys.One sentence summaryA universal vascular bundle detection model can efficiently dissect vascular bundles in Phyllostachys, and the radial gradient change of vascular bundles in cross-section are found highly consistent.

Parametric Generation of Random Distribution of Fibers in Long-Fiber Reinforced Composites and Micromechanical FE Analysis

2010 ◽  
Vol 452-453 ◽  
pp. 117-120
Author(s):  
Zhen Qing Wang ◽  
Xiao Qiang Wang ◽  
Ji Feng Zhang ◽  
Song Zhou
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Fiber Volume Fraction ◽  
Random Distribution ◽  
Volume Fraction ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Parametric Generation ◽  
High Fiber ◽  
Damage Initiation

A method for the parametric generation of the transversal cross-section microstructure model of unidirectional long-fiber reinforced composite (LFRC) is presented in this paper. Meanwhile, both the random distribution of the fibers and high fiber volume fraction are considered in the algorithm. The fiber distribution in the cross-section is generated through random movements of the fibers from their initial regular square arrangement. Furthermore, cohesive zone element is introduced into modeling the interphase between the fiber and the matrix. All these processes are carried out by the secondary development of the finite element codes (ABAQUS) via Python language programming. Based on the model generated, micromechanical finite element analysis (FEA) is performed to predict the damage initiation and subsequent evolution of the composites. The results show that this technique is capable of capturing the random distribution nature of these composites even for high fiber volume fraction. Moreover, the results prove that a good agreement with the experimental results is found.

Monitoring of mechanical properties of prestressed glass fiber epoxy composites over 12 months after fabrication

2021 ◽  
pp. 002199832110047
Author(s):  
Mahmoud Mohamed ◽  
Siddhartha Brahma ◽  
Haibin Ning ◽  
Selvum Pillay
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Flexural Strength ◽  
Compressive Residual Stress ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Epoxy Composites ◽  
Flexural Properties ◽  
Initial Increase ◽  
Fiber Volume

Fiber prestressing during matrix curing can significantly improve the mechanical properties of fiber-reinforced polymer composites. One primary reason behind this improvement is the generated compressive residual stress within the cured matrix, which impedes cracks initiation and propagation. However, the prestressing force might diminish progressively with time due to the creep of the compressed matrix and the relaxation of the tensioned fiber. As a result, the initial compressive residual stress and the acquired improvement in mechanical properties are prone to decline over time. Therefore, it is necessary to evaluate the mechanical properties of the prestressed composites as time proceeds. This study monitors the change in the tensile and flexural properties of unidirectional prestressed glass fiber reinforced epoxy composites over a period of 12 months after manufacturing. The composites were prepared using three different fiber volume fractions 25%, 30%, and 40%. The results of mechanical testing showed that the prestressed composites acquired an initial increase up to 29% in the tensile properties and up to 32% in the flexural properties compared to the non-prestressed counterparts. Throughout the 12 months of study, the initial increase in both tensile and flexural strength showed a progressive reduction. The loss ratio of the initial increase was observed to be inversely proportional to the fiber volume fraction. For the prestressed composites fabricated with 25%, 30%, and 40% fiber volume fraction, the initial increase in tensile and flexural strength dropped by 29%, 25%, and 17%, respectively and by 34%, 26%, and 21%, respectively at the end of the study. Approximately 50% of the total loss took place over the first month after the manufacture, while after the sixth month, the reduction in mechanical properties became insignificant. Tensile modulus started to show a very slight reduction after the fourth/sixth month, while the flexural modulus reduction was observed from the beginning. Although the prestressed composites displayed time-dependent losses, their long-term mechanical properties still outperformed the non-prestressed counterparts.

scholarly journals Effect of Fiber Volume Fraction on Behavior of Concrete Beams Made with Recycled Concrete Aggregates

2019 ◽  
Vol 253 ◽  
pp. 02004
Author(s):  
Wael Alnahhal ◽  
Omar Aljidda
Keyword(s):  
Fiber Volume Fraction ◽  
Concrete Beams ◽  
Volume Fraction ◽  
Recycled Concrete ◽  
Flexural Behavior ◽  
Beam Specimen ◽  
Rc Beam ◽  
Fiber Volume ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates

This study investigates the effect of using different volume fractions of basalt macro fibers (BMF) on the flexural behavior of concrete beams made with 100% recycled concrete aggregates (RCA) experimentally. A total of 4 reinforced concrete (RC) beam specimens were flexural tested until failure. The parameter investigated included the BMF volume fraction (0%, 0.5%, 1%, and 1.5%). The testing results of the specimens were compared to control beam specimen made with no added fibers. The experimental results showed that adding BMF improves the flexural capacity of the tested beams.

The Effects of Fiber Volume Fraction on the Experiment Modal Behavior of 45°/-45° Carbon Fiber Plain Woven Fabric/Epoxy Resin Composites

2012 ◽  
Vol 583 ◽  
pp. 150-153
Author(s):  
Qian Liu ◽  
Xiao Yuan Pei ◽  
Jia Lu Li
Keyword(s):  
Carbon Fiber ◽  
Epoxy Resin ◽  
Natural Frequency ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Laminated Composites ◽  
Woven Fabric ◽  
Resin Composites ◽  
Fiber Volume ◽  
Epoxy Resin Composites

The modal properties of carbon fiber woven fabric (with fiber orientation of 45°/-45°) / epoxy resin composites with different fiber volume fraction were studied by using single input and single output free vibration of cantilever beam hammering modal analysis method. The effect of different fiber volume fraction on the modal parameters of laminated composites was analyzed. The experimental results show that with the fiber volume fraction increasing, the natural frequency of laminated composites becomes larger and damping ratio becomes smaller. The fiber volume fraction smaller, the peak value of natural frequency becomes lower and the attenuating degree of acceleration amplitude becomes faster.

Sign in / Sign up

Export Citation Format

Share Document