Rolling shear modulus and strength of beech wood laminations

Holzforschung ◽  
2016 ◽  
Vol 70 (8) ◽  
pp. 773-781 ◽  
Author(s):  
Simon Aicher ◽  
Zachary Christian ◽  
Maren Hirsch
Keyword(s):  
Shear Strength ◽  
Shear Modulus ◽  
Beech Wood ◽  
European Beech ◽  
Rolling Shear ◽  
Shear Properties ◽  
Shear Moduli ◽  
Major Interest ◽  
Characteristic Values ◽  
Cross Layers

Abstract Previous research indicated that the rolling shear properties of European beech wood (Fagus sylvatica) are considerably higher than those of softwood. The aim of the presented investigation was to substantiate previous data on rolling shear modulus and strength of European beech wood and to further evaluate its substitution of softwoods in applications where shear properties are influential, namely as cross layers in cross-laminated timber (CLT). Further, the effect of the annual ring orientation within the boards on shear modulus and strength was of major interest. The beech specimens comprised four different sawing patterns, classified unambiguously with reference to the pith location. The shear properties were determined by 50, two-plate shear tests with specimen cross-section dimensions of 33 mm × 135 mm. A mean rolling shear modulus of 370 N mm-2 was obtained, whereby no significant detrimental effect for pith boards with cracks was observed. In agreement with continuum mechanics, the semi-quarter-sawn boards revealed the highest shear moduli whereas the quarter-sawn boards showed roughly 30% lower values. The mean rolling shear strength was 5.6 N mm-2 for all specimens, whereby pith specimens resulted in generally lower values. The 5% quantile, disregarding pith specimens, was 4.5 N mm-2. In conclusion, the rolling shear strength and modulus exceed the respective characteristic values for softwoods by roughly factors of 5 and 7, indicating great potential for beech wood cross-layers in CLT.

ASSESSMENT OF SHEAR ANALOGY AND TIMOSHENKO METHOD FOR ANALYZING HYBRID CLT UNDER OUT-OF-PLANE LOADING

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
MD Tanvir Rahman ◽  
Mahud Ashraf ◽  
Kazem Ghabraie ◽  
Mahbube Subhani
Keyword(s):  
Shear Modulus ◽  
Numerical Models ◽  
Natural Material ◽  
Fiber Direction ◽  
Viable Option ◽  
Rolling Shear ◽  
Significant Interest ◽  
Out Of Plane ◽  
Superior Mechanical Properties ◽  
Cross Layers

Timber is a natural material which offers superior mechanical properties in parallel to fiber direction when compared against those in perpendicular to the fibers. Cross-laminated timber (CLT) is made up of layers of structurally graded timber, orthogonally oriented in layers whereby it can sustain loading in both directions. CLT is often used as floor panels, and hence, its performance under out-of-plane loading is of significant interest. Low rolling shear modulus resulting in higher shear flexibility of the cross-layers tend to decrease the effective bending stiffness of CLT sections. Developing hybrid CLT using timbers with higher rolling shear modulus as cross-layers in CLT is considered a viable option to improve its performance under out-of-plane loading. The present study investigates the performance of shear analogy and Timoshenko methods in predicting the deflection of hybrid CLT panels while considering different span-to-depth ratios and various combinations of rolling shear modulus. Numerical models were developed to conduct a parametric study and obtained deflection results were compared against those calculated from the shear analogy method and Timoshenko method. It was observed that for CLT with a small span-to-depth ratio and cross-layers made from material with higher rolling shear modulus, the deflection calculated from the analytical methods deviates from the values obtained from the numerical model.

Dynamic Shear Properties of Rubberlike Polymers

1951 ◽  
Vol 24 (3) ◽  
pp. 507-519 ◽  
Author(s):  
I. L. Hopkins
Keyword(s):  
Shear Modulus ◽  
Dynamic Properties ◽  
Dynamic Shear ◽  
Shear Properties ◽  
Shear Moduli ◽  
Test Range ◽  
Simple Apparatus

Abstract A simple apparatus for determining the dynamic properties of elastomers in shear at audio frequencies is appraised. Typical values of shear modulus and viscosity for several elastomers are given, both at room conditions and at 150° F. The frequencies of test range from 100 to 5250 cycles per second, the shear moduli from 0.5×106 to 480×106 dynes per sq. cm. and the viscosities from 20 to 75,000 poises.

The effect of edge gaps on shear strength and rolling shear modulus of cross laminated timber panels

2020 ◽  
Vol 259 ◽  
pp. 119710
Author(s):  
Charles Gardner ◽  
William G. Davids ◽  
Roberto Lopez-Anido ◽  
Benjamin Herzog ◽  
Russell Edgar ◽  
...  
Keyword(s):  
Shear Strength ◽  
Shear Modulus ◽  
Rolling Shear ◽  
Cross Laminated Timber

scholarly journals Multidirectional measures of shear modulus in skeletal muscle

2021 ◽  
Author(s):  
William E Reyna ◽  
Eric J. Perreault ◽  
Daniel Ludvig
Keyword(s):  
Skeletal Muscle ◽  
Shear Modulus ◽  
Material Properties ◽  
Joint Motion ◽  
Muscle Type ◽  
Shear Properties ◽  
Fiber Alignment ◽  
Shear Moduli ◽  
Whole Muscle ◽  
Other Orientation

The material properties of muscle play a central role in how muscle resists joint motion, transmits forces internally, and repairs itself. While many studies have evaluated muscle's tensile material properties, few have investigated muscle's shear properties. None of which have taken into account muscle's anisotropic structure or investigated how different muscle architecture affect muscle's shear properties. The objective of this study was to quantify the shear moduli of skeletal muscle in three orientations relevant to the function of whole muscle. We collected data from the extensor digitorum longus, tibialis anterior, and soleus harvested from both hindlimbs of 12 rats. These muscles were chosen to further evaluate the consistency of shear moduli across muscles with different architectures. We calculated the shear modulus in three orientations: parallel, perpendicular, and across with respect to muscle fiber alignment; while the muscle was subjected to increasing shear strain. For all muscles and orientations, the shear modulus increased with increasing strain. The shear modulus measured perpendicular to fibers was greater than in any other orientation. Despite architectural differences between muscles, we did not find a significant effect of muscle type on shear modulus. Our results show that in rat, muscles' shear moduli vary with respect to fiber orientation and are not influenced by architectural differences in muscles.

A Review of Shear Properties for Malaysian Tropical Timber in Structural Size

2021 ◽  
Vol 1025 ◽  
pp. 325-333
Author(s):  
Muhammad Bazli Faliq Mohd Puaad ◽  
Zakiah Ahmad ◽  
Nurul Faiizin Abdul Aziz ◽  
Adrina Rosseira Abu Talip ◽  
Mohd Hanafie Yasin
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Shear Modulus ◽  
Physical And Mechanical Properties ◽  
Torsion Test ◽  
Timber Species ◽  
Shear Properties ◽  
Tropical Timber ◽  
Structural Size ◽  
Numerous Data

In recent years, the studies on producing data on physical and mechanical properties of Malaysian timber specimens have evolved from small clear specimen to structural size specimen, where most of the research method was based on the American Standard Testing Manual ASTM D198. Numerous data regarding mechanical properties on structural size specimen have been produced through this method, such as bending and compression test. Unfortunately, studies on shear properties on structural size timber are very scarce. It has reviewed that the global timber researchers are focusing to produce data on shear properties of European timber species such as Oak, Spruce and Pine where both shear strength and shear modulus data were obtained from bending and torsion test. Furthermore, from the review of the existing literature, it is clear that there is no proper studies focusing on development of shear properties of Malaysian tropical timber, especially torsion test in accordance with EN 408:2010. Therefore, the aim of this study is to investigate the shear properties (shear strength and shear modulus) of Malaysian Tropical Timber in large size.

scholarly journals Evaluating Timoshenko Method for Analyzing CLT under Out-of-Plane Loading

Buildings ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 184
Author(s):  
MD Tanvir Rahman ◽  
Mahmud Ashraf ◽  
Kazem Ghabraie ◽  
Mahbube Subhani
Keyword(s):  
Shear Modulus ◽  
Shear Deformation ◽  
Numerical Study ◽  
Wood Products ◽  
Tangential Plane ◽  
Rolling Shear ◽  
Laminated Veneer Lumber ◽  
Engineered Wood ◽  
Out Of Plane ◽  
Cross Layers

Cross-laminated timber (CLT) is an engineered wood product made up of layers of structurally graded timber, where subsequent layers are oriented orthogonally to each other. In CLT, the layers oriented in transverse direction, generally termed as cross-layer, are subjected to shear in radial–tangential plane, which is commonly known as rolling shear. As the shear modulus of cross-layers is significantly lower than that in other planes, CLT exhibits higher shear deformation under out-of-plane loading in contrast to other engineered wood products such as laminated veneer lumber (LVL) and glue laminated timber (GLT). Several analytical methods such as Timoshenko, modified gamma and shear analogy methods were proposed to account for this excessive shear deformation in CLT. This paper focuses on the effectiveness of Timoshenko method in hybrid CLT, in which hardwood cross-layers are used due to their higher rolling shear modulus. A comprehensive numerical study was conducted and obtained results were carefully analyzed for a range of hybrid combinations. It was observed that Timoshenko method could not accurately predict the shear response of CLTs with hardwood cross layers. Comprehensive parametric analysis was conducted to generate reliable numerical results, which were subsequently used to propose modified design equations for hybrid CLTs.

scholarly journals Effects of Grain Pattern on the Rolling Shear Properties of Wood in Cross-Laminated Timber

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 668
Author(s):  
Guofang Wu ◽  
Yong Zhong ◽  
Haiqing Ren
Keyword(s):  
Shear Modulus ◽  
Mechanical Performance ◽  
Wood Products ◽  
Rolling Shear ◽  
Shear Moduli ◽  
Factors Affecting ◽  
Cross Laminated Timber ◽  
Aspect Ratios ◽  
Shear Property ◽  
Pure Rolling

Rolling shear modulus and strength are the key factors affecting the mechanical performance of some wood products such as cross-laminated timber (CLT). As reported, rolling shear property strongly depends on the sawing pattern such as the aspect ratio and grain direction (grain mode). However, the mechanism behind this phenomenon has not yet been clarified. In this work, the rolling shear modulus and strength of spruce-pine-fir (SPF) with different grain modes and aspect ratios were experimentally investigated. In addition, a theoretical investigation was carried out to reveal the mechanism behind this phenomenon. The results exhibited that the rolling shear moduli of 0° and 90° grain-mode wood were the same. This value can be called the pure rolling shear modulus. Rolling shear modulus of wood with angles other than 0° and 90° can be calculated from the pure rolling shear modulus and grain angle. Therefore, this modulus can be called the apparent rolling shear modulus. Thus, using 0° and 90° grain-mode specimens to determine the pure rolling shear modulus and strength of wood is recommended.

scholarly journals Microstructure and shear properties of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints under thermal cycling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jianguo Cui ◽  
Keke Zhang ◽  
Di Zhao ◽  
Yibo Pan
Keyword(s):  
Shear Strength ◽  
Thermal Cycling ◽  
Solder Joints ◽  
High Reliability ◽  
Sharp Decrease ◽  
Thermal Shock Test ◽  
Shear Properties ◽  
Equivalent Time ◽  
Ultrasonic Assisted ◽  
Reliability Of Solder Joints

AbstractThrough ultrasonic wave assisted Sn2.5Ag0.7Cu0.1RExNi/Cu (x = 0, 0.05, 0.1) soldering test and − 40 to 125 °C thermal shock test, the microstructure and shear properties of Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints under thermal cycling were studied by the SEM, EDS and XRD. The results show that the Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints with high quality and high reliability can be obtained by ultrasonic assistance. When the ultrasonic vibration power is 88 W, the ultrasonic-assisted Sn2.5Ag0.7Cu0.1RE0.05Ni/Cu solder joints exhibits the optimized performance. During the thermal cycling process, the shear strength of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints had a linear relationship with the thickness of interfacial intermetallic compound (IMC). Under the thermal cycling, the interfacial IMC layer of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints consisted of (Cu,Ni)6Sn5 and Cu3Sn. The thickness of interfacial IMC of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints was linearly related to the square root of equivalent time. The growth of interfacial IMC of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints had an incubation period, and the growth of IMC was slow within 300 cycles. And after 300 cycles, the IMC grew rapidly, the granular IMC began to merge, and the thickness and roughness of IMC increased obviously, which led to a sharp decrease in the shear strength of the solder joints. The 0.05 wt% Ni could inhibit the excessive growth of IMC, improve the shear strength of solder joints and improve the reliability of solder joints. The fracture mechanism of ultrasonic-assisted Sn2.5Ag0.7Cu0.1RExNi/Cu solder joints changed from the ductile–brittle mixed fracture in the solder/IMC transition zone to the brittle fracture in the interfacial IMC.

scholarly journals Estimation of quadriceps femoris muscle dysfunction in the early period after surgery of the knee joint using shear-wave elastography

2018 ◽  
Vol 4 (1) ◽  
pp. e000381 ◽  
Author(s):  
Makoto Kawai ◽  
Keigo Taniguchi ◽  
Tomoyuki Suzuki ◽  
Masaki Katayose
Keyword(s):  
Shear Modulus ◽  
Knee Joint ◽  
Patient Group ◽  
Quadriceps Femoris ◽  
Control Group ◽  
Muscle Dysfunction ◽  
Shear Moduli ◽  
Quadriceps Femoris Muscle ◽  
Contraction Ratio ◽  
Femoris Muscle

ObjectivesOrthopaedic surgery of the knee joint results in functional deterioration of the quadriceps femoris muscle. However, little is known about quadriceps femoris muscle dysfunction in the early postsurgical period. Therefore, we examined the stiffness of the quadriceps femoris muscle in the early postsurgical period.MethodsSeven patients and seven healthy controls performed quadriceps contraction exercises. In resting and contraction conditions, the shear modulus, muscle thickness and pennation angle were measured for the vastus medialis (VM), vastus lateralis (VL) and the rectus femoris (RF) using ultrasound elastography.ResultsThe shear moduli of the VM, VL and RF in the control group did not significantly interact, while the shear moduli in the patient group did show a significant interaction. In the resting condition, there was no difference between the unaffected and affected sides in the patient group, but the shear moduli of the VM and VL in the contraction condition was significantly lower on the affected side than the unaffected side.The contraction ratios between muscles by limbs did not significantly interact. However, there were main effects due to muscle and limb factors. The VM and VL had a significantly higher contraction ratio than the RF, and the control and unaffected limbs had a higher contraction ratio than the affected limb.ConclusionThe results demonstrated a decrease in muscle stiffness during contraction in patients with quadriceps femoris dysfunction. Measurement of the shear modulus has potential as a new evaluation index and with high sensitivity to decreases in muscle contraction.

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