Damping Properties of Selected Tropical Wood Species from Cameroon Forest Assessed Via Free Transverse Vibration Method | Chapter 1 | Engineering Research: Perspectives on Recent Advances Vol. 8

Despite the diverse use of wood in industrial construction, some technological properties of tropical wood species are still little known. This concerns more particularly the logarithmic decrement, viscous damping ratio, loss factor, quality factor and specific damping ratio, which were little studied and documented in the literature, which hinders the reliable design of structures under dynamic solicitation. This study describes a non-destructive method for determining the damping properties of wood. It was based on the analysis of the attenuation of the free transverse vibrations of a fixed support-free specimen following excitation. Cameroonian forests abound with important species that were much in demand for structural applications and were often subjected to dynamic loads. However, in the literature and in the available databases, very little information was available on the vibration properties of these wood species. To solve this problem, three specimens of twenty-four wood species with a cross-section of 10 mm × 20 mm, with a length of 1600 mm, were prepared and subjected to a free vibration test in the fixed support-free configuration. The accelerations as a function of time were obtained. Displacement data were derived from recorded accelerations, and the logarithmic decrement was calculated using the first twenty-one amplitude peaks. Using known relationships between parameters, the viscous damping ratio, loss factor, quality factor and specific damping ratio were deduced. The results obtained were relatively variable between species. Among the studied wood species, Azobé exhibited the highest damping ratio, while Wengé showed the lowest. Compared with the data available in the literature for the same species, there was a considerable difference.

 

Author (s) Details

 

Nkibeu Jean Bertin
Laboratory Civil Engineering and Mechanics, National Advanced School of Engineering, The University of Yaoundé 1, Cameroon.

 

Makomra Valentin
Department of Civil Engineering, National Advanced School of Public Works, Cameroon.

 

Moussa Sali
Laboratory of Materials, Mechanics and Civil Engineering, National Advanced School of Engineering, The University of Maroua, Cameroon and Department of Civil Engineering, Advanced Teachers Training College of the Technical Education, The University of Douala, Cameroon.

 

MadjaDoumbaye Jerémie
Department of Civil Engineering, National Advanced School of Public Works, Cameroon.

 

 

Please see the book here:- https://doi.org/10.9734/bpi/erpra/v8/5605

Mechanical Properties of Metal Rubber Inner Core of O-Type Seal with Large Ring-To-Diameter Ratio: A Recent Study| Chapter 1 | Research Aspects in Chemical and Materials Sciences Vol. 6

 In order to address the failings of common rubber seals, to a degree extreme- and depressed-temperature opposition, smooth stale, and inadequate load-posture act, O-type ore rubber seals accompanying a abundant ring-to-diameter percentage were constructed utilizing the cold stamping method and without a stain fortify line as raw material. Heat situation and porosity were examined for their belongings on the compression and pliable features of test samples. It was found during uniaxial condensation experiment that the test sample shown typical hysteresis characteristics, what the misfortune factor and strength wantonness of the sample accompanying the same capacity but different porosity increased accompanying the decline in porosity. The heat-medicated sample's loss determinant and strength disappearance were less than those of the not cooked sample. As a result, strength entertainment and change of loss determinant are two together raised with abating porosity. Four samples accompanying variable levels of porosity had their yield strength, greatest stiffness, and modulus of stretchiness evaluated. It was found that the three versification raised as porosity decreased. Additionally, as porosity curtailed, the generated power of the thermal situation red-pink. The three earlier parameters were all usually bred. This illustrated that metal elastic matters have good machinelike properties in extreme-hotness surroundings, effectively proposing the issue of common gaze' susceptibility to developing and breakdown under usual working environments. This has important manufacturing applications in two together belief and practice.

Author(s) Details:

Zhiying Ren,
School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China and Engineering Research Center for Metal Rubber, Fuzhou University, Fuzhou 350116, China.

Linwei Shi,
School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China and Engineering Research Center for Metal Rubber, Fuzhou University, Fuzhou 350116, China.

Zihao Huang,
School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China and Engineering Research Center for Metal Rubber, Fuzhou University, Fuzhou 350116, China.

Yangyang Yang,
School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China and Engineering Research Center for Metal Rubber, Fuzhou University, Fuzhou 350116, China.

Hongbai Bai,
School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350116, China and Engineering Research Center for Metal Rubber, Fuzhou University, Fuzhou 350116, China.

Please see the link here: https://stm.bookpi.org/RACMS-V6/article/view/9329