scholarly journals Experimental study on LBL beams

2019 ◽  
Vol 275 ◽  
pp. 01026
Author(s):  
Chenjie Zhao ◽  
Xiaohong Xiong ◽  
Zhenhua Xiong ◽  
Kangwen Wu ◽  
Zhen Cao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Elastic Modulus ◽  
Standard Deviation ◽  
Cross Section ◽  
Beam Theory ◽  
Bending Moment ◽  
Modulus Of Rupture ◽  
Loading Process ◽  
The Mean

Six specimens were made and tested to study the mechanical properties of LBL beams. The mean ultimate loading value is 68.39 MPa with a standard deviation of 6.37 MPa, giving a characteristic strength (expected to be exceeded by 95% of specimens) of 57.91 MPa, and the mean ultimate deflection is 53.3 mm with a standard deviation of 5.5 mm, giving the characteristic elastic modulus of 44.3 mm. The mean ultimate bending moment is 20.18 kN.m with a standard deviation of 1.88 kN.m, giving the characteristic elastic modulus of 17.08 kN.m. The mean elastic modulus is 9688 MPa with a standard deviation of 1765 MPa, giving the characteristic elastic modulus of 6785 MPa, and the mean modulus of rupture is 93.3 MPa with a standard deviation of 8.6 MPa, giving the characteristic elastic modulus of 79.2 MPa. The strain across the cross-section for all LBL beams is basically linear throughout the loading process, following standard beam theory.

Performance Enhancement of Recycled Aggregate Concrete – An Experimental Study

2021 ◽  
Author(s):  
Sivamani Jagan ◽  
Thurvas Renganathan Neelakantan ◽  
Palaniraj Saravanakumar
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Elastic Modulus ◽  
Performance Enhancement ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Coarse Aggregates ◽  
Durability Properties ◽  
Concrete Mixtures

Extensive studies have been performed on the mechanical and durability properties of the concrete prepared with recycled coarse aggregates (RCA), however, only modest consideration has been given to the studies on the behaviour of RAC prepared by alternative mixing approach techniques. This study presents the mechanical properties of the recycled aggregate concrete (RAC) with different percentages of RCA prepared by normal mixing approach (NMA), two-stage mixing approach (TSMA) and sand enveloped mixing approach (SEMA) techniques. The manufactured concrete mixtures were tested for compression, tension, flexure and elastic modulus at 7, 28 and 90 days. The results indicate that the mechanical properties of the RAC (with 100% of RCA) prepared through TSMA and SEMA were improved by 9.36 and 12.14% at 28 days. Perhaps, prolonged curing to TSMA and SEMA mixtures improved the mechanical properties of the RAC that is nearly equal to normal aggregate concrete (NAC) prepared by NMA.

On Torsion and Transverse Flexure of Orthotropic Elastic Plates

1980 ◽  
Vol 47 (4) ◽  
pp. 855-860 ◽  
Author(s):  
E. Reissner
Keyword(s):  
Cross Section ◽  
Beam Theory ◽  
Bending Moment ◽  
Rate Of Change ◽  
Elastic Plates ◽  
Shear Center ◽  
Explicit Consideration ◽  
The Difference ◽  
Shear Deformable ◽  
Shear Deformable Plates

The equations of transverse bending of shear-deformable plates are used for the derivation of a system of one-dimensional equations for beams with unsymmetrical cross section, with account for warping stiffness, in addition to bending, shearing, and twisting stiffness. Significant results of the analysis include the observation that the rate of change of differential bending moment is given by the difference between torque contribution due to plate twisting moments and torque contribution due to plate shear stress resultants; a formula for shear center location which generalizes a result by Griffith and Taylor so as to account for transverse shear deformability and end-section warping restraint; a second-order compatibility equation for the differential bending moment; a contracted boundary condition of support for unsymmetrical cross-section beam theory in place of an explicit consideration of the warping deformation boundary layer; and construction of a problem where the effect of the conditions of support of the beam is such as to give noncoincident shear center and twist center locations.

scholarly journals Experimental Study on the Stiffness of Steel Beam-to-Upright Connections for Storage Racking Systems

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2949
Author(s):  
Florin Dumbrava ◽  
Camelia Cerbu
Keyword(s):  
Experimental Study ◽  
Cross Section ◽  
Bending Moment ◽  
Steel Beam ◽  
Rotational Stiffness ◽  
Safety Coefficient ◽  
Flexural Tests ◽  
Different Thickness

The aspects regarding the stiffness of the connections between the beams that support the storage pallets and the uprights is very important in the analysis of the displacements and stresses in the storage racking systems. The main purpose of this paper is to study the effects of both upright thickness and tab connector type on the rotational stiffness and on the capable bending moment of the connection. For this purpose, a number of 18 different groups of beam-connector-upright assemblies are prepared by combining three types of beams (different sizes of the box cross section), three kinds of uprights profiles (with a different thickness of the section walls), and two types of connectors (four-tab connectors and five-tab connectors). Flexural tests were carried out on 101 assemblies. For the assemblies containing the uprights having the thickness of 1.5 mm, the five-tab connector leads to a higher value of the capable moment and higher rotational stiffness than similar assemblies with four-tab connectors. A contrary phenomenon happens in case of the assemblies containing the upright profiles having a thickness of 2.0 mm regarding the capable design moment. It is shown how the safety coefficient of connection depends on both the rotational stiffness and capable bending moment.

Effect of Silica Fume on Mechanical Properties and Carbonation Resistance of Concrete

2012 ◽  
Vol 238 ◽  
pp. 161-164 ◽  
Author(s):  
Qing Long Wang ◽  
Jun Chao Bao
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Elastic Modulus ◽  
Silica Fume ◽  
Compression Strength ◽  
Considerable Increase ◽  
Carbonation Resistance

A designed experimental study has been conducted to investigate the effect of silica fume on mechanical properties and carbonation resistance of concrete, a large number of experiments have been carried out in this study. The results indicate that the addition of silica fume has improved the compression strength and elastic modulus of concrete. A considerable increase for the compression strength and elastic modulus of the concrete was observed by increasing the dosage of silica fume. Besides, the addition of silica fume can improve the carbonation resistance of the concrete composite evidently, and the carbonation resistance is becoming better and better as the silica fume content is increasing gradually.

Effect of Powder Types on Mechanical Properties of D-Gun Coatings

1997 ◽  
Author(s):  
M.C. Kim ◽  
S.B. Kim ◽  
J.W. Hong
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Fracture Strain ◽  
Modulus Of Rupture ◽  
Special Device ◽  
High Fracture ◽  
Spray Coatings ◽  
Bend Tests ◽  
Point Bend ◽  
Four Point Bend Test

Abstract Mechanical properties of WC-Co D-Gun coatings produced from various powders were determined by using a four-point bend test equipped with a special device for strain measurements. The MOR(Modulus of Rupture), elastic modulus, fracture strain and toughness were measured from stress-strain curves using the four-point bend tests. The fracture strength values were increased in the order of clad, sintered, agglomerated(no densification), blended and cast & crushed powder coatings. The Co content blended with WC-Co cermet powders significantly increased fracture strain values and decreased elastic modulus values. It was found that the type of powder more significantly influenced the mechanical properties of D-Gun coatings than the composition of powders. The toughness of thermal spray coatings was increased by using WC-Co powders (high MOR) blended with self-fluxing alloy powders (high fracture strain).

Experimental Study on Welding Process of TC4 Titanium Alloy with Different Welding Wires

2021 ◽  
Vol 1035 ◽  
pp. 57-62
Author(s):  
Guo Qiang Shang ◽  
Li Ping Li ◽  
Xin Nan Wang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Tensile Strength ◽  
Titanium Alloy ◽  
Cross Section ◽  
Welding Process ◽  
Alloy Wire ◽  
Tc4 Titanium Alloy ◽  
Weld Area ◽  
Evolution Of Microstructure

In present study, the effects of different welding wires on the evolution of microstructure and mechanical properties of TC4 titanium alloy test plates were studied. The results show that the test plates welded by TA20 titanium alloy wire, TC3 titanium alloy wire and TC4 titanium alloy wire are well formed, no defects are found in the cross section of the weld. The microstructures of these test plates are similar, and needle-like martensite exists in the weld area. In comparison, this is little obvious difference in tensile strength among these test plates welded by different welding wires, while the plates welded by TC4 titanium alloy has better elongation, contraction of aera, impact toughness and better balance of strength and toughness.

Variability Assessment of the Compressive and Tensile Strength of Fibred Earthen Composites

2022 ◽  
Author(s):  
Philippe Poullain ◽  
Mircea Barnaure ◽  
Stéphanie Bonnet
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Standard Deviation ◽  
Probability Density Function ◽  
Building Materials ◽  
Mean Value ◽  
Rammed Earth ◽  
The Mean ◽  
The Many

Earthen composites (rammed earth, cob, adobe, daub, CEB...) are experiencing renewed interest from builders due to the many advantages of these building materials, and in particular their eco-friendliness. Nevertheless, the widespreading of these materials, as certified materials and conforming to construction standards, comes against the lack of data concerning their mechanical properties. Indeed, the literature generally gives the average values of the properties without indicating the number of specimens tested neither the distribution of the data. Yet, the mean value of the compressive strength is not enough to assess the reliability of a given earthen composite to build a wall and it would be better to indicate the value of a defined percentile (characteristic value just like with concrete composites). The aim of this paper is to analyze the data about the mechanical properties (tensile and compressive strength) obtained on different formulations of cob including natural fibres or not. The tests performed allowed to determine the probability density function and the average values, the standard deviation and the percentiles, for the various properties.

Thermo-Mechanical Treatment to Improve Properties of Sisal Fibres for Composites

2010 ◽  
Vol 636-637 ◽  
pp. 253-259 ◽  
Author(s):  
L.A.C. Motta ◽  
Vanderley M. John ◽  
Vahan Agopyan
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Cross Section ◽  
Mechanical Treatment ◽  
Moisture Absorption ◽  
Thermo Mechanical Treatment ◽  
The Cross

The cross section variation, mechanical properties and moisture absorption of vegetable sisal fibres compressed at temperatures of 120, 160 and 200 °C were determined and compared with values obtained in non-compressed fibres. The thermo-mechanical treatment carried out resulted in a relevant increasing of fibre stiffness (elastic modulus) and decreasing of fibre moisture absorption.

scholarly journals Monte Carlo Simulation of the Formation of Snowflakes

2005 ◽  
Vol 62 (5) ◽  
pp. 1529-1544 ◽  
Author(s):  
Ken-ichi Maruyama ◽  
Yasushi Fujiyoshi
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Standard Deviation ◽  
Cross Section ◽  
Collision Cross Section ◽  
Initial Distribution ◽  
Sphere Model ◽  
Aggregate Model ◽  
Mean Diameter ◽  
The Mean

Abstract A stochastic microphysical model of snow aggregation that combines a simple aggregation model with a Monte Carlo method was developed. Explicit treatment of the shape of individual snowflakes in the new model facilitates examination of the structure of snowflakes and the relationships between the parameters of the generated snowflakes, such as mass versus diameter, in addition to comparisons with observations. In this study, complexities in the shape of snowflakes are successfully simulated, and the understanding of the evolution of their size distribution is advanced. The mean diameter of snow particles evolves more rapidly in the aggregate model than in the sphere model. However, growth rates of the aggregates greatly depend on the collision section of particles in aggregation. The mean mass of snowflakes in the aggregate model grows more slowly than the mass in the sphere model when the sum of the particle cross section is used as the collision cross section. The mean mass grows more quickly when a circle is used whose radius is the sum of the radii of two particles. Sensitivity experiments showed that aggregation also depends on the mean and standard deviation of the initial distribution, and on the density of constituent particles.

Effects of Osteopontin Deficiency and Aging on Nanomechanics of Mouse Bone

2004 ◽  
Vol 841 ◽  
Author(s):  
B. Kavukcuoglu ◽  
C. West ◽  
D. T. Denhardt ◽  
A. B. Mann
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Standard Deviation ◽  
Bone Mineralization ◽  
Bone Matrix ◽  
Age Groups ◽  
Matrix Proteins ◽  
Significant Difference ◽  
Bone Matrix Proteins ◽  
New Treatments

ABSTRACTOsteopontin (OPN), a phosphorylated glycoprotein, is among the most abundant non-collageneous bone matrix proteins produced by osteoblasts and osteoclasts. OPN has been implicated in bone formation, resorption and remodeling. However, previous studies have presented contradictory results regarding the effect of OPN on the mechanics and microstructure of bone. This study has used nanoindentation to identify local variations in elastic modulus and hardness of OPN deficient (OPN -/-) and wild-type control (OPN+/+) mouse bones. Specifically, the study has looked at changes in the mechanical properties of OPN-/- and OPN+/+ mouse bones with the mouse's age. Cortical sections of femurs from different age groups ranging from 3 weeks to 58 weeks were tested and compared. The results suggest that there are large, abrupt variations in mechanical properties across the femur's radial section for 3-week-old mouse bone. The hardness (H) drops significantly towards the inner and outer sections so the cortical bone has a mean H=3.66 GPa with a standard deviation of 2.44 GPa. In contrast, the hardness of the 58-week-old mouse bone had a standard deviation of 0.35 GPa and a mean H=1.45 GPa. The hardness across the radial axis of the 58-week-old bone was found to be quite uniform. The elastic modulus showed similar variations to the hardness with respect to age and position on the bone. We conclude that the mechanical properties of the mouse bones decrease substantially with maturity, and statistically the hardness and elastic modulus are more uniform in mature bones than young ones. Surprisingly we found a similar variation in both OPN-/- and OPN+/+ bones, with no statistically significant difference in the mechanical properties of the OPN -/- and OPN+/+ bones. The results for OPN-/- and OPN+/+ mouse bones are particularly important as control of OPN activity has been postulated as a potential treatment for bone pathologies that exhibit a change in the bone mineralization, such as osteoporosis, osteopetrosis and Paget's disease. Understanding the effects of OPN on bone mechanics is a vital step in the development of these new treatments.

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