Effect of a high loading rate on the compressive properties of beech wood in the longitudinal direction

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 4093-4105
Author(s):  
Kristijan Radmanović ◽  
Robert Roginić ◽  
Ružica Beljo Lučić ◽  
Juraj Jovanović ◽  
Matija Jug ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Specific Energy ◽  
Maximum Stress ◽  
Beech Wood ◽  
Compressive Force ◽  
Longitudinal Direction ◽  
Mathematical Functions ◽  
Plastic Properties ◽  
Loading Rates ◽  
High Loading Rate

Because of its hardness, wear-resistance, strength, and bending capabilities, beech wood is a widely-used hardwood in Europe. It is mainly used for furniture, floors, construction, veneer boards, and laminated wood. For such uses, the mechanical properties are very important, especially in cases of impact loads. The aim of this work is to analyse the mechanical properties of beech wood samples exposed to compressive force in the longitudinal direction based on different loading rates (in the range from 10 mm/min to 500 mm/min). Stress–strain diagrams were made with the experimental data, and mathematical functions were fit to them. Using the fit functions, the following properties of beech wood samples were determined: the stress and strain at the elastic limit; the maximum stress and associated strain; the modulus of elasticity; the tangent modulus; the specific energy of elastic strain; and the specific energy of plastic strain. The results showed that by increasing the loading rates, the elastic properties of beech wood increase, while the analysed plastic properties do not show a clear tendency of changes with increase of the loading rates.

Architected functionally graded porous lattice structures for optimized elastic-plastic behavior

2020 ◽  
Vol 234 (8) ◽  
pp. 1099-1116 ◽  
Author(s):  
Mahshid Mahbod ◽  
Masoud Asgari ◽  
Christian Mittelstedt
Keyword(s):  
Mechanical Properties ◽  
Energy Absorption ◽  
Specific Energy ◽  
Elastic Moduli ◽  
Maximum Stress ◽  
Functionally Graded ◽  
Plastic Behavior ◽  
Lattice Structures ◽  
Porous Structures ◽  
Specific Energy Absorption

In this paper, the elastic–plastic mechanical properties of regular and functionally graded additively manufactured porous structures made by a double pyramid dodecahedron unit cell are investigated. The elastic moduli and also energy absorption are evaluated via finite element analysis. Experimental compression tests are performed which demonstrated the accuracy of numerical simulations. Next, single and multi-objective optimizations are performed in order to propose optimized structural designs. Surrogated models are developed for both elastic and plastic mechanical properties. The results show that elastic moduli and the plastic behavior of the lattice structures are considerably affected by the cell geometry and relative density of layers. Consequently, the optimization leads to a significantly better performance of both regular and functionally graded porous structures. The optimization of regular lattice structures leads to great improvement in both elastic and plastic properties. Specific energy absorption, maximum stress, and the elastic moduli in x- and y-directions are improved by 24%, 79%, 56%, and 9%, respectively, compared to the base model. In addition, in the functionally graded optimized models, specific energy absorption and normalized maximum stress are improved by 64% and 56%, respectively, in comparison with the base models.

Development of Combined Machining Modes, Investigation of Mechanical Properties and Structure of Deformed Semi-Finished Products from Alloy 01417

2020 ◽  
Vol 992 ◽  
pp. 498-503
Author(s):  
S. Sidelnikov ◽  
D. Voroshilov ◽  
M. Motkov ◽  
M. Voroshilova ◽  
V. Bespalov
Keyword(s):  
Mechanical Properties ◽  
Rare Earth Metals ◽  
Electrophysical Properties ◽  
Intermediate Annealing ◽  
Plastic Properties ◽  
Bar Rolling ◽  
Annealing Temperatures ◽  
Continuous Ingot ◽  
The Wire ◽  
Deformation Modes

The article presents the results of studies on the production of wire with a diameter of 0.5 mm from aluminum alloy 01417 with a content of rare-earth metals (REM) in the amount of 7-9% for aircraft construction needs. The deformation modes, the experimental technique and equipment for the implementation of the proposed technology described. The wire was obtained by drawing and bar rolling with subsequent drawing from a rod with a diameter of 5 mm, obtained previously using the process of combined rolling-extruding (CRE) from a continuous ingot with a diameter of 12 mm, cast in an electromagnetic mold (EMM). The wire obtained by the presented technology was subjected to 4 different heat treatment modes with annealing temperatures from 350 to 500 °C and holding time of 1 h in the furnace to achieve mechanical and electrophysical properties corresponding to TS 1-809-1038-2018. The level of strength and plastic properties obtained in the course of research required only one intermediate annealing. The microstructure of the wire was investigated and the modes were revealed that made it possible to obtain the required level of mechanical properties and electrical resistivity, satisfying TS 1-809-1038-2018.

Influence of loading rates on morpholgy and mechanical properties of PLA/clay nanocomposites

2012 ◽  
Vol 7 (5) ◽  
pp. 390
Author(s):  
Mustapha Kaci ◽  
Lynda Zaidi ◽  
Stéphane Bruzaud ◽  
Alain Bourmaud ◽  
Pascal Médéric ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Clay Nanocomposites ◽  
Loading Rates

Comparison of mechanical properties of thermally modified wood at growth ring and cell wall level by means of instrumented indentation tests

Holzforschung ◽  
2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Stefanie Stanzl-Tschegg ◽  
Wilfried Beikircher ◽  
Dieter Loidl
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Thermal Treatment ◽  
Mechanical Performance ◽  
Growth Ring ◽  
Beech Wood ◽  
Thermal Modification ◽  
Wood Structure ◽  
Instrumented Indentation ◽  
Indentation Tests

Abstract Thermal modification is a well established method to improve the dimensional stability and the durability for outdoor use of wood. Unfortunately, these improvements are usually accompanied with a deterioration of mechanical performance (e.g., reduced strength or higher brittleness). In contrast, our investigations of the hardness properties in the longitudinal direction of beech wood revealed a significant improvement with thermal modification. Furthermore, we applied instrumented indentation tests on different hierarchical levels of wood structure (growth ring and cell wall level) to gain closer insights on the mechanisms of thermal treatment of wood on mechanical properties. This approach provides a variety of mechanical data (e.g., elastic parameters, hardness parameters, and viscoelastic properties) from one single experiment. Investigations on the influence of thermal treatment on the mechanical properties of beech revealed similar trends on the growth ring as well as the on the cell wall level of the wood structure.

Reverse Plasticity in Nanoindentation

2007 ◽  
Vol 1049 ◽  
Author(s):  
Yongjiang Huang ◽  
Nursiani Indah Tjahyono ◽  
Jun Shen ◽  
Yu Lung Chiu
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Glass Transition ◽  
Single Crystal ◽  
Metallic Glasses ◽  
Deformation Mechanisms ◽  
Glass Transition Temperatures ◽  
Loading Rates ◽  
Nanoindentation Experiment ◽  
Properties Of Materials

AbstractThis paper summarises our recent cyclic nanoindentation experiment studies on a range of materials including single crystal and nanocrystalline copper, single crystal aluminium and bulk metallic glasses with different glass transition temperatures. The unloading and reloading processes of the nanoindentation curves have been analysed. The reverse plasticity will be discussed in the context of plastic deformation mechanisms involved. The effect of loading rates on the mechanical properties of materials upon cyclic loading will also be discussed.

Influence of loading rates on mechanical properties of cobalt-chromium alloys

BDJ ◽  
1975 ◽  
Vol 138 (8) ◽  
pp. 295-298 ◽  
Author(s):  
M H Reisbick ◽  
A A Caputo
Keyword(s):  
Mechanical Properties ◽  
Cobalt Chromium ◽  
Loading Rates ◽  
Chromium Alloys

The effect of long-term annealing simulating the parameters of dry storage of VVER-1000 fuel rods on the mechanical properties of E110 alloy shells in the longitudinal direction

2021 ◽  
Vol 4 ◽  
pp. 42-49
Author(s):  
G. P. Kobylyansky ◽  
◽  
А. О. Mazaev ◽  
Е. А. Zvir ◽  
S. G. Eremin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Relative Elongation ◽  
Mechanical Test ◽  
Longitudinal Direction ◽  
Radiation Defects ◽  
Thermal Tests ◽  
Fuel Rods ◽  
Dry Storage

Presented are the results of mechanical tensile tests of longitudinal (segmental) samples cut from the midsection of claddings spent as VVER-1000 FA during one- and six-year campaigns and subject to thermal tests in helium at 480 °С during 468 full days. An average burnup of these fuel rods achieved ~ 20 and ~ 70 (MW·day)/kg U, respectively. The tests followed the examinations for cladding mechanical properties performed using the tests results for ring samples cut from the specified fuel rods. These fuel rods were tested in the experiments to determine impact of long-term thermal tests that model dry storage conditions on mechanical properties of Zr E110 claddings. Based on mechanical tests results at room temperature and at 380 °С there was determined as follows: ultimate strength sв, yield strength s0,2 and total relative elongation d0 of claddings length-wise on the fuel rod segments at the fuel column midsection. The obtained characteristics were compared to corresponding values for initial (unirradiated) cladding tubes and mechanical test results of the ring samples in the transverse direction. Long-term thermal tests have led to partial return to initial (before operation) values sв, s0,2 and d0 of radiation-hardened claddings; this return was more prominent in the longitudinal direction than in the transverse one. A radiation hardening decrease was accompanied with an increase in total relative elongation values in both cladding directions. Anisotropy of yield strength has changed as well. These changes can be explained by partial annealing of radiation defects, which are obstacles to dislocation movements during cladding strain. The morphology of above radiation defects is different in various sliding planes in texturized grains of cladding material.

Mechanical properties of the tracheal mucosal membrane in the rabbit. II. Morphometric analysis

2000 ◽  
Vol 88 (3) ◽  
pp. 1022-1028 ◽  
Author(s):  
Lu Wang ◽  
Kenneth L. Pinder ◽  
Joel L. Bert ◽  
Mitsushi Okazawa ◽  
Peter D. Paré
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Mechanical Load ◽  
Morphological Structure ◽  
Longitudinal Direction ◽  
Smooth Muscle Contraction ◽  
Elastic Fibers ◽  
Tissue Samples ◽  
Mucosal Membrane ◽  
Simple Geometry

Folding of the airway mucosal membrane provides a mechanical load that impedes airway smooth muscle contraction. Mechanical testing of rabbit tracheal mucosal membrane showed that the membrane is stiffer in the longitudinal than in the circumferential direction of the airway. To explain this difference in the mechanical properties, we studied the morphological structure of the rabbit tracheal mucosal membrane in both longitudinal and circumferential directions. The collagen fibers were found to form a random meshwork, which would not account for differences in stiffness in the longitudinal and circumferential directions. The volume fraction of the elastic fibers was measured using a point-counting technique. The orientation of the elastic fibers in the tissue samples was measured using a new method based on simple geometry and probability. The results showed that the volume fraction of the elastic fibers in the rabbit tracheal mucosal membrane was ∼5% and that the elastic fibers were mainly oriented in the longitudinal direction. Age had no statistically significant effect on either the volume fraction or the orientation of the elastic fibers. Linear correlations were found between the steady-state stiffness and the quantity of the elastic fibers oriented in the direction of testing.

Sign in / Sign up

Export Citation Format

Share Document