scholarly journals Prediksi Nilai Kuat Lentur Kayu Tropis Berdasarkan Nilai Modulus Elastis

2021 ◽  
Vol 18 (1) ◽  
pp. 27-42
Author(s):  
Ali Awaludin ◽  
Urwatul Wusqo
Keyword(s):  
Wave Velocity ◽  
Stress Wave ◽  
Stress Wave Velocity

Dalam SNI 7973:2013, nilai modulus elastisitas statik kayu (MoEs) digunakan sebagai dasar pengelompokan mutu kayu. Nilai MoEs juga dapat digunakan untuk memprediksi sifat mekanika kayu yang lain. Penelitian ini melakukan kajian untuk mendapatkan persamaan yang dapat digunakan untuk memprediksi nilai berdasarkan nilai rata rata modulus elastisitas dan persamaan untuk mendapatkan nilai kekuatan lentur (MoR) berdasarkan nilai MoEsnya dari kayu tropis yang ada di Indonesia. Uji lentur statik dilakukan berdasarkan EN 408, sementara itu uji lentur dinamik dilakukan menggunakan metode stress wave velocity. Selain itu, data sekunder hasil pengujian lentur dari para peneliti terdahulu juga digunakan dalam penelitian ini. Dari hasil analisis, nilai adalah sebesar 0,754 dari . Analisis regresi linear menunjukkan bahwa nilai MoR dapat didekati dengan persamaan 𝑀𝑜𝑅 = −1,359 + 0,0061, dimana dari persamaan ini dapat diketahui bahwa nilai desain acuan yang ada pada Tabel 4.2.1 SNI 7973:2013 cenderung memberikan faktor keamanan yang memadai. Pengujian lentur dinamik kayu menunjukkan bahwa hubungan antara modulus elastisitas dinamik (MoEd) dan MoEsdapat didekati melalui persamaan = −1330,1 + 1,254 dengan koefisien determinasi () sebesar 0,69.

Propagation velocity model of stress waves in larch wood (Larix gmelinii) three-dimensional space with different moisture contents

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6680-6695
Author(s):  
Xiwen Wei ◽  
Liping Sun ◽  
Hongjv Zhou ◽  
Yang Yang ◽  
Yifan Wang ◽  
...  
Keyword(s):  
Moisture Content ◽  
Wave Velocity ◽  
Stress Wave ◽  
Propagation Velocity ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Stress Waves ◽  
Moisture Contents ◽  
Direction Angle ◽  
Stress Wave Velocity

Based on the effects of stress wave propagation in larch (Larix gmelinii) wood, the propagation mechanism of stress wave was explored, and a theoretical model of the propagation velocity of stress waves in the three-dimensional space of wood was developed. The cross and longitudinal propagation velocities of stress wave were measured in larch wood under different moisture contents (46% to 87%, 56% to 96%, 20% to 62%, and 11% to 30%) in a laboratory setting. The relationships between the propagation velocity of stress waves and the direction angle or chord angle with different moisture contents were analyzed, and the three-dimensional regression models among four parameters were established. The analysis results indicated that under the same moisture content, stress wave velocity increased as the direction angle increased and decreased as chord angle increased, and the radial velocity was the largest. Under different moisture contents, stress wave velocity gradually decreased as moisture content increased, and the stress wave velocity was more noticeably affected by moisture content when moisture content was below the fiber saturation point (FSP, 30%). The nonlinear regression models of the direction angle, chord angle, moisture content, and the propagation velocity of stress wave fit the experiment data well (R2 ≥ 0.97).

STRESS WAVE VELOCITY AND CRACK SYSTEM OF A MEDIUM *

1974 ◽  
Vol 22 (4) ◽  
pp. 710-721
Author(s):  
V. SCHENK ◽  
Z. SCHENKOVA
Keyword(s):  
Wave Velocity ◽  
Stress Wave ◽  
Crack System ◽  
Stress Wave Velocity

scholarly journals Influence of moisture content on estimating Young’s modulus of full-scale timber using stress wave velocity

2017 ◽  
Vol 63 (3) ◽  
pp. 225-235 ◽  
Author(s):  
Mariko Yamasaki ◽  
Chika Tsuzuki ◽  
Yasutoshi Sasaki ◽  
Yuji Onishi
Keyword(s):  
Moisture Content ◽  
Young’S Modulus ◽  
Wave Velocity ◽  
Stress Wave ◽  
Young's Modulus ◽  
Full Scale ◽  
Stress Wave Velocity

Stress Wave Velocities in Bovine Patellar Tendon

1998 ◽  
Vol 120 (3) ◽  
pp. 321-326 ◽  
Author(s):  
J. J. Crisco ◽  
T. C. Dunn ◽  
R. D. McGovern
Keyword(s):  
Elastic Modulus ◽  
Strain Rate ◽  
Wave Velocity ◽  
Patellar Tendon ◽  
Stress Wave ◽  
Stress Waves ◽  
Force Transmission ◽  
Static Testing ◽  
Wave Velocities ◽  
Stress Wave Velocity

The velocity of longitudinal stress waves in an elastic body is given by the square root of the ratio of its elastic modulus to its density. In tendinous and ligamentous tissue, the elastic modulus increases with strain and with strain rate. Therefore, it was postulated that stress wave velocity would also increase with increasing strain and strain rate. The purpose of this study was to determine the velocity of stress waves in tendinous tissue as a function of strain and to compare these values to those predicted using the elastic modulus derived from quasi-static testing. Five bovine patellar tendons were harvested and potted as bone–tendon–bone specimens. Quasi-static mechanical properties were determined in tension at a deformation rate of 100 mm/s. Impact loading was employed to determine wave velocity at various strain levels, achieved by preloading the tendon. Following impact, there was a measurable delay in force transmission across the specimen and this delay decreased with increasing tendon strain. The wave velocities at tendon strains of 0.0075, 0.015, and 0.0225 were determined to be 260 ± 52 m/s, 360 ± 71 m/s, and 461 ± 94 m/s, respectively. These velocities were significantly (p < 0.01) faster than those predicted using elastic moduli derived from the quasi-static tests by 52, 45, and 41 percent, respectively. This study has documented that stress wave velocity in patellar tendon increases with increasing strain and is underestimated with a modulus estimated from quasi-static testing.

Effect of cross-sectional change of a board specimen on stress wave velocity determination

Holzforschung ◽  
2005 ◽  
Vol 59 (2) ◽  
pp. 230-231 ◽  
Author(s):  
Ferenc Divos ◽  
Levente Denes ◽  
Guillermo Iñiguez
Keyword(s):  
Wave Velocity ◽  
Stress Wave ◽  
Cross Sectional ◽  
Stress Wave Velocity
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