Mechanical Properties of Wood and Timber Bridge Evaluation

2014 ◽  
Vol 587-589 ◽  
pp. 1381-1385
Author(s):  
Ling Ling Yu ◽  
Jie Jun Wang ◽  
Te Huang
Keyword(s):  
Mechanical Properties ◽  
Structural Integrity ◽  
Strength Properties ◽  
Structural Elements ◽  
Bridge Evaluation ◽  
Bridge Structures ◽  
And Performance ◽  
Inspection Techniques ◽  
Non Destructive ◽  
Timber Bridges

Wood possesses material properties that may be significantly different from other materials normally encountered in structural design. It is necessary for the engineer to have a general understanding of the properties and characteristics that affect the strength and performance of wood in bridge applications. This paper discusses the mechanical properties of wood, including elastics properties and strength properties. Timber bridge are often exposed to harsh environment conditions. Over time, this exposure can lead to deterioration. In turn, this deterioration may lead to a loss of structural integrity that is detrimental to the structure and its users. Timber structural elements are susceptible to degradation due to environmental and loading conditions. A variety of inspection techniques can be employed to locate damage and decay in timber members in order to maintain structural performance. Methods of non-destructive techniques for timber bridges are getting more and more important. This paper presents several non-destructive methods to timber bridge structures.

scholarly journals Creation of Polymer Coatings for Improving of Protective Properties of Surfaces

2021 ◽  
Vol 12 (2) ◽  
pp. 2698-2702
Author(s):  
A.A. Orekhov, Et. al.
Keyword(s):  
Mathematical Modeling ◽  
Mechanical Properties ◽  
Polymer Coatings ◽  
Strength Properties ◽  
Structural Elements ◽  
Properties Of Coatings ◽  
Mechanical Loads ◽  
Protective Properties ◽  
Modeling Methods ◽  
Metal Plates

In this paper, the preparation of polymer coatings on the surface of metal structural elements is considered to improve their physical, mechanical and strength properties. It is shown that the behavior of substrate samples under mechanical loads can be estimated using mathematical modeling methods. The properties of coatings and the mechanical properties of coated and uncoated metal plates have been evaluated. Methods for constructing mathematical models of metal plates of various structures are proposed.

Application of a portable indentation rig with Rockwell indenter to determine mechanical properties and residual stresses on an aluminum plate

2020 ◽  
Vol 55 (7-8) ◽  
pp. 246-257
Author(s):  
Saba Salmani Ghanbari ◽  
Amir-Hossein Mahmoudi
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Indentation Load ◽  
Instrumented Indentation ◽  
Unknown Parameters ◽  
Plastic Properties ◽  
Wide Range ◽  
Portable Apparatus ◽  
Non Destructive

Measuring residual stresses is still a dilemma in many engineering applications. It is even more crucial when the industrial requirements demand for a non-destructive technique in order to avoid compromising the structural integrity of the engineering components. Furthermore, estimating the mechanical properties of the materials, especially when the components are aged, is of importance. Instrumented indentation has gained much interest in recent years. There are many studies in the literature which are focused on measuring residual stresses or mechanical properties using instrumented indentation. Since in many cases there is no possibility of transferring large samples or those under service, for possible measurements, having a portable rig can be very useful. Furthermore, indentation procedure is a low-cost non-destructive method with high accuracy which is able to measure the plastic properties of material as well as its residual stresses on which the designing and construction of the portable apparatus were based. The instrumented indentation testing details were followed according to the ASTM E2546-15 standard practice. In this research, a wide range of simulations were performed on a group of aluminum alloys in order to estimate the equi-biaxial residual stresses by analyzing the indentation load–displacement curves which were obtained from the experimental outcomes. Then neural networks were employed to estimate the unknown parameters. The performance accuracy of the designed portable apparatus and the acceptable precision of the introduced method were then verified with experimental tests performed on Al 2024-T351.

Instrumented Indentation Technique to Measure Flow Properties: A Novel Way to Enhance the Accuracy of Integrity Assessment

2003 ◽  
Author(s):  
Jae-Il Jang ◽  
Yeol Choi ◽  
Yun-Hee Lee ◽  
Jung-Suk Lee ◽  
Dongil Kwon ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Crack Detection ◽  
Structural Integrity ◽  
Instrumented Indentation ◽  
Flow Properties ◽  
Integrity Assessment ◽  
Indentation Technique ◽  
Failure Assessment ◽  
Similar Vein ◽  
Non Destructive

While most in-field technologies for structural integrity diagnosis focus on precise crack detection, the instrumented indentation technique has emerged as one of the most practically useful technologies for non-destructive and quantitative in-field measurement of mechanical properties. In a similar vein, here an advanced indentation technique for determining tensile properties and its application to structural integrity assessment are introduced and discussed. This novel indentation technique can enhance the accuracy of fitness-for-service (FFS) assessment by application to failure assessment diagram (FAD) construction.

Verification of the Ultrasonic Qualification for Structural Integrity of Partially Concrete Embedded Steel Elements

2009 ◽  
Vol 65 ◽  
pp. 69-78 ◽  
Author(s):  
J. Alfredo López ◽  
Francisco J. Carrión ◽  
Juan A. Quintana ◽  
Didier Samayoa-Ochoa ◽  
María G. Lomelí ◽  
...  
Keyword(s):  
Grain Size ◽  
Structural Integrity ◽  
Fatigue Cracks ◽  
Good Condition ◽  
Ultrasonic Inspection ◽  
Structural Elements ◽  
Ultrasonic Evaluation ◽  
Statistical Mechanical ◽  
Microstructural Integrity ◽  
Non Destructive

Failure of one upper anchorage element in a cable-stayed bridge and its consequent analysis concluded that the main cause of the failure was a deficient heat treatment that resulted in large micro structural grain size and low fracture toughness, vulnerable to fatigue damage. Previous research studies demonstrated that ultrasonic evaluation could provide some insight of the microstructural integrity by correlating the ultrasonic response to the grain size. Thus, this technique was used to inspect the 112 elements in service in the bridge and 16 were qualified as structurally deficient, without direct verification of the grain size, since these elements were partially embedded in the concrete structure. Late rehabilitation of the bridge considered the replacement of the 16 structural deficient anchorage elements, plus 4 elements qualified in good condition, to complete a reliability analysis for the remaining 92 elements from the statistical mechanical properties of the removed pieces. Rehabilitation made possible the confirmation of the initial diagnosis made by ultrasonic inspection and fatigue cracks were identified in some elements. This study demonstrated that the ultrasonic non destructive evaluation is highly reliable for structural integrity qualification of steel structural elements partially embedded in concrete.

scholarly journals Mechanical Properties of Glass Fiber Composites Reinforced by Textile Fabric

2015 ◽  
Vol 1 ◽  
pp. 133
Author(s):  
Arturs Macanovskis ◽  
Andrejs Krasnikovs ◽  
Olga Kononova ◽  
Galina Harjkova ◽  
Vladislav Yevstignejevs
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Polymer Matrix ◽  
Strength Properties ◽  
Machine Building ◽  
Structural Elements ◽  
Structural Element ◽  
Glass Fiber Composites ◽  
Material Volume ◽  
External Loads

<p class="R-AbstractKeywords"><span lang="EN-US">Interest to structural application of textile reinforced polymer matrix composite materials (CM) is growing during last years. In different branches of machine building, aerospace, automotive and others industries we can find structural elements preferably be produced using such reinforcement. At the same time, such materials are exhibiting elastic and strength properties scatter. In the framework of the present investigation, we observe yarn penetrated by a resin in a composite as a reinforcing “macro” fiber. Such “macro” fiber mechanical properties were measured experimentally, for this purpose was produced and was tested by tension until fracture fiber samples, having different length. Then was elaborated and was realized structural strength probabilistic model. In the textile geometry, was picked out repeating structural element – polymer matrix volume with two curved “macro” fiber’s chunks inside it. Complete composite material volume is possible to represent as a set of repeating structural elements. External loads application leads to disperse structural elements failure. Neighboring to ruptured elements are overloaded leading to higher probability to fail for them. Using FEM was modeled stress state in “macro” fibers inside CM. Then, was numerically obtained stress distribution in composite material, having different number of broken loops. Probabilities of different numbers of failed elements were calculated.  Strength probability function, based on Weibull approach was obtained. CM samples were tested under tension and obtained results were compared with numerical modeling as well as were analyzed.</span></p>

Destructive and non-destructive evaluation of seven hardwoods and analysis of data correlation

Holzforschung ◽  
2014 ◽  
Vol 68 (8) ◽  
pp. 951-956 ◽  
Author(s):  
Dhanya Ponneth ◽  
Anoop Elaveettil Vasu ◽  
Jayasree Chandramana Easwaran ◽  
Aadarsh Mohandass ◽  
Shakti S. Chauhan
Keyword(s):  
Mechanical Properties ◽  
Specific Gravity ◽  
Penetration Depth ◽  
Physical And Mechanical Properties ◽  
Tectona Grandis ◽  
Strength Properties ◽  
Acacia Auriculiformis ◽  
Tropical Hardwood ◽  
Hardwood Species ◽  
Non Destructive

Abstract Wood physical and mechanical properties in seven tropical hardwood species viz., Acacia auriculiformis A. Cunn. ex Benth., Artocarpus hirsutus Lamk., Artocarpus heterophyllus Lamk., Swietenia macrophylla King, Xylia dolabriformis Benth., Hevea braziliensis (H.B.K.) M. A.), and Tectona grandis L.f. have been studied by means of destructive and non-destructive techniques (NDT). Mechanical strength properties and specific gravity were evaluated by conventional methods. NDT was carried out by a Pilodyn and Treesonic Microsecond Timer (TMT) to measure a steel pin penetration depth into wood and dynamic MOE, respectively. In focus was the question, whether NDT data are suitable predictors for physical and mechanical properties of the indicated hardwood species. Dynamic MOE obtained by TMT correlated strongly positive with all the strength properties studied, except shearing stress. TMT data also correlated very well to static bending MOE and MOR. A linear relationship was found between Pilodyn steel pin penetration depth and oven dry specific gravity in all the species. Both Pilodyn and TMT proved to be useful predictors of timber properties, and these instruments have a high potential for timber grading.

Metallic Nanoneedles Arrays for TEM Sample Preparation “Lift-Out”

2012 ◽  
Author(s):  
Romaneh Jalilian ◽  
David Mudd ◽  
Neil Torrez ◽  
Jose Rivera ◽  
Mehdi M. Yazdanpanah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Microscope ◽  
Sample Preparation ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Beam System ◽  
Transmission Electron ◽  
Nanoneedle Array ◽  
Superior Mechanical Properties ◽  
And Performance

Abstract The sample preparation for transmission electron microscope can be done using a method known as "lift-out". This paper demonstrates a method of using a silver-gallium nanoneedle array for a quicker sharpening process of tungsten probes with better sample viewing, covering the fabrication steps and performance of needle-tipped probes for lift-out process. First, an array of high aspect ratio silver-gallium nanoneedles was fabricated and coated to improve their conductivity and strength. Then, the nanoneedles were welded to a regular tungsten probe in the focused ion beam system at the desired angle, and used as a sharp probe for lift-out. The paper demonstrates the superior mechanical properties of crystalline silver-gallium metallic nanoneedles. Finally, a weldless lift-out process is described whereby a nano-fork gripper was fabricated by attaching two nanoneedles to a tungsten probe.

Modern european methods of non-destructive diagnostics of bridge structures

2019 ◽  
Vol 2019 (19) ◽  
pp. 38-53
Author(s):  
Ihor Ihor ◽  
◽  
Nataliia Nataliia ◽  
Valerii Vyrozhemskyi ◽  
◽  
...  
Keyword(s):  
Bridge Structures ◽  
Non Destructive

Effect of nickel on formation of transition layer during liquid-phase aluminizing of titanium

2020 ◽  
pp. 313-317
Author(s):  
A.I. Kovtunov ◽  
Yu.Yu. Khokhlov ◽  
S.V. Myamin
Keyword(s):  
Mechanical Properties ◽  
Liquid Phase ◽  
Intermetallic Layer ◽  
Reaction Diffusion ◽  
Strength Properties ◽  
Effect Of Temperature ◽  
Nickel Concentration ◽  
Aluminum Melt ◽  
Titanium Aluminum ◽  
Titanium Foam

Titanium—aluminum, titanium—foam aluminum composites and bimetals obtained by liquid-phase methods, are increasingly used in industry. At the liquid-phase methods as result of the reaction diffusion of titanium and aluminum is formed transitional intermetallic layer at the phase boundary of the composite, which reduces the mechanical properties of titanium and composite. To reduce the growth rate of the intermetallic layer between the layers of the composite and increase its mechanical properties, it is proposed to alloy aluminum melt with nickel. The studies of the interaction of titanium and molten aluminum alloyed with nickel made it possible to establish the effect of temperature and aluminizing time on the thickness, chemical and phase compositions of the transition intermetallic layer. The tests showed the effect of the temperature of the aluminum melt, the nickel concentration on the strength properties of titanium—aluminum bimetal.

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