scholarly journals Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

2021 ◽  
Vol 13 (10) ◽  
pp. 5494
Author(s):  
Lucie Kucíková ◽  
Michal Šejnoha ◽  
Tomáš Janda ◽  
Jan Sýkora ◽  
Pavel Padevět ◽  
...  

Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual bending strength. A negative impact of high temperature on residual strength has also been observed from simple tensile tests, although limited to a very narrow layer adjacent to the charring front not even exceeding a typically adopted value of the zero-strength layer d0=7 mm. On the contrary, the impact on stiffness is relatively mild supporting the thermal recovery property of wood.

2019 ◽  
Vol 58 (1) ◽  
pp. 218-225
Author(s):  
Damian S. Nakonieczny ◽  
Agata Sambok ◽  
Magdalena Antonowicz ◽  
Marcin Basiaga ◽  
Zbigniew K. Paszenda ◽  
...  

Abstract Purpose: This part of the study focuses on the influence of zirconia heat treatment for surface morphology, phase composition and mechanical properties Methods: Zirconia samples was prepared with ISO 13356:2013 and ISO 14704:2008 recommendations. X-ray diffraction, observations (SEM) and (AFM), microhardness (Olivera & Phara method), and static bending test (4PBT) were taken. Results: characterization of YSZ and high temperature heat treatment has clearly shown that the aging process influences the change in phase composition of the material, significantly worsening the topography. In turn, re-treatment of the high temperature made after the artificial aging process results in reverse transformation of the desired tetragonal phase, but does not affect the improvement of surface morphology. Conclusions: The research made it possible to assess the negative impact of the zirconium oxide aging simulation process. Because of the failure to achieve the intended results, it was also proved that the high-temperature re-processing was not appropriate.


2021 ◽  
Vol 40 (1) ◽  
pp. 325-336
Author(s):  
Binqi Zhang ◽  
Shaodong Ju ◽  
Chuangang Liu ◽  
Yingwen Ma ◽  
Haiyan Chen ◽  
...  

Abstract High-temperature tensile tests at 25, 150, 250, and 350°C were carried out on 30CrMo, 42CrMo, 1Cr13, and 304 steels. The changes in tensile strength, yield strength, elongation, and area reduction ratio with temperature were determined. By analyzing the fracture morphology and the relationship between strength and hardness, the influence of high-temperature mechanical properties on crack sensitivity and the mechanism of crack formation is discussed. Experimental results indicated that both the tensile and yield strengths of the four steels gradually decrease with the increase in temperature. The yield ratios of 30CrMo, 42CrMo, 1Cr13, and 304 steels are, respectively, 0.71–0.77, 0.79–0.86, 0.84–0.88, and 0.33–0.40 which shows that among the four steels, 304 has the best ductility, while 1Cr13 has the worst ductility. As for the four steels, the values of reduction ratio of area are greater than 60%, except for 42CrMo which is slightly lower than 60% at 150 and 250°C, indicating that the four steels have low crack sensitivity within the test temperature range. Ductile fracture is the main fracture mechanism for 30CrMo, 42CrMo, and 304 steel, whereas brittle fracture is predominant for 1Cr13. There is a linear regression relationship between the strength and hardness at different temperatures. The obtained linear regression relationship can be used to predict and estimate the strength of 30CrMo, 42CrMo, 1Cr13, and 304 steels at different temperatures according to the hardness results.


Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1094
Author(s):  
M. A. Lakhdari ◽  
F. Krajcarz ◽  
J. D. Mithieux ◽  
H. P. Van Landeghem ◽  
M. Veron

The impact of microstructure evolution on mechanical properties in superduplex stainless steel UNS S32750 (EN 1.4410) was investigated. To this end, different thermomechanical treatments were carried out in order to obtain clearly distinct duplex microstructures. Optical microscopy and scanning electron microscopy, together with texture measurements, were used to characterize the morphology and the preferred orientations of ferrite and austenite in all microstructures. Additionally, the mechanical properties were assessed by tensile tests with digital image correlation. Phase morphology was not found to significantly affect the mechanical properties and neither were phase volume fractions within 13% of the 50/50 ratio. Austenite texture was the same combined Goss/Brass texture regardless of thermomechanical processing, while ferrite texture was mainly described by α-fiber orientations. Ferrite texture and average phase spacing were found to have a notable effect on mechanical properties. One of the original microstructures of superduplex stainless steel obtained here shows a strength improvement by the order of 120 MPa over the industrial material.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1242
Author(s):  
Olga Mysiukiewicz ◽  
Paulina Kosmela ◽  
Mateusz Barczewski ◽  
Aleksander Hejna

Investigations related to polymer/metal composites are often limited to the analysis of the electrical and thermal conductivity of the materials. The presented study aims to analyze the impact of aluminum (Al) filler content (from 1 to 20 wt%) on the rarely investigated properties of composites based on the high-density polyethylene (HDPE) matrix. The crystalline structure, rheological (melt flow index and oscillatory rheometry), thermal (differential scanning calorimetry), as well as static (tensile tests, hardness, rebound resilience) and dynamic (dynamical mechanical analysis) mechanical properties of composites were investigated. The incorporation of 1 and 2 wt% of aluminum filler resulted in small enhancements of mechanical properties, while loadings of 5 and 10 wt% provided materials with a similar performance to neat HDPE. Such results were supported by the lack of disturbances in the rheological behavior of composites. The presented results indicate that a significant content of aluminum filler may be introduced into the HDPE matrix without additional pre-treatment and does not cause the deterioration of composites’ performance, which should be considered beneficial when engineering PE/metal composites.


2013 ◽  
Vol 811 ◽  
pp. 9-13 ◽  
Author(s):  
Zakaria Boumerzoug ◽  
Zakaria Boumerzoug ◽  
Vincent Ji

In this present investigation, the mechanical properties of industrial drawn copper wires have been studied by creep tests, tensile tests and hardness Vickers. The effect of prior heat treatments at 500°C for different time on the drawn wires behavior was the main goal of this investigation. We have found that these heat treatments influenced the creep behavior of drawn wires and recorded shape curves. The creep tests were applied under ambient atmosphere at 240 °C. The creep duration before rupture decreased with the prior heat treatment time. The creep tests results were confirmed by tensile tests. A relationship between the hardness and the ultimate tensile strength of this industrial material has been established. Optical and scanning electron microscopy observations have been also used. Cross section observations of the wire after tensile or creep-rupture tests have shown that the mechanism of rupture was mainly controlled by the void formation.


2010 ◽  
Vol 56 (6) ◽  
pp. 437-443 ◽  
Author(s):  
Thomas Goodrich ◽  
Nadia Nawaz ◽  
Stefanie Feih ◽  
Brian Y. Lattimer ◽  
Adrian P. Mouritz

2012 ◽  
Vol 602-604 ◽  
pp. 627-630 ◽  
Author(s):  
Kyu Sik Kim ◽  
Kee Ahn Lee ◽  
Jong Ha Kim ◽  
Si Woo Park ◽  
Kyu Sang Cho

Inconel 713C alloy was tried to manufacture by using MIM(Metal Injection Molding) process. The high-temperature mechanical properties of MIMed Inconel 713C were also investigated. Processing defects such as pores and binders could be observed near the surface. Tensile tests were conducted from room temperature to 900°C. The result of tensile tests showed that this alloy had similar or somewhat higher strengths (YS: 734 MPa, UTS: 968 MPa, elongation: 7.16 % at room temperature) from RT to 700°C than those of conventional Inconel 713C alloys. Above 800°C, however, ultimate tensile strength decreased rapidly with increasing temperature (lower than casted Inconel 713C). Based on the observation of fractography, initial crack was found to have started near the surface defects and propagated rapidly. The superior mechanical properties of MIMed Inconel 713C could be obtained by optimizing the MIM process parameters.


Agronomy ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 145 ◽  
Author(s):  
Viola Devasirvatham ◽  
Daniel Tan

Global climate change has caused severe crop yield losses worldwide and is endangering food security in the future. The impact of climate change on food production is high in Australia and globally. Climate change is projected to have a negative impact on crop production. Chickpea is a cool season legume crop mostly grown on residual soil moisture. High temperature and terminal drought are common in different regions of chickpea production with varying intensities and frequencies. Therefore, stable chickpea production will depend on the release of new cultivars with improved adaptation to major events such as drought and high temperature. Recent progress in chickpea breeding has increased the efficiency of assessing genetic diversity in germplasm collections. This review provides an overview of the integration of new approaches and tools into breeding programs and their impact on the development of stress tolerance in chickpea.


Author(s):  
Kee-Nam Song ◽  
Sung-Deok Hong ◽  
Hong-Yoon Park

PHE (Process Heat Exchanger) is a key component in transferring the high temperature heat generated from a VHTR (Very High Temperature Reactor) to the chemical reaction for massive production of hydrogen. A performance test on a small-scale PHE prototype made of Hastelloy-X is currently undergoing in a small-scale gas loop at the Korea Atomic Energy Research Institute. Previous researches on the high-temperature structural analysis of the small-scale PHE prototype had been performed using parent material properties over the whole region. In this study, high-temperature elastic structural analysis considering mechanical properties in the weld zone was performed and the analysis result was compared with previous researches.


2015 ◽  
Vol 1127 ◽  
pp. 1-8
Author(s):  
Martin Rund ◽  
Josef Volák ◽  
Miroslava Šindelářová

The evaluation of actual mechanical properties of the in-service structures after some time of operation or determination of local properties for detailed FEM simulation yields the necessity to obtain relevant material data with high accuracy from small volume of the experimental material. Therefore, non-destructive or semi-destructive techniques using small size samples are being developed. The use of small-scale samples also enables the evaluation of material properties in various locations of tested component; for example, the mechanical properties of the individual regions of welds, local properties determination for properties anisotropy assessment and properties determination in cases when small volume of the experimental material is available e.g. residual service life assessment of in service components, bulk nanostructured materials… There are shown results of small size tensile tests (M-TT) and small sized fatigue tests (SFT). In the case of small size specimens testing a machining becomes more pronounced that in the case of standard sized specimens. The current study brings information on the machining influence on the expected results obtained by small size specimens in the case of quasi-static tensile tests and fatigue test.


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