scholarly journals EFFECT OF CHROMIUM COATINGS ON THE MECHANICAL PROPERTIES OF Zr1Nb FUEL CLADDINGS IN LONGITUDINAL AND TRANSVERSE DIRECTIONS

2019 ◽  
pp. 142-146
Author(s):  
V.А. Belous ◽  
V.N. Voyevodin ◽  
S.V. Gozhenko ◽  
Y.А. Krainyuk ◽  
А.S. Kuprin ◽  
...  

This study was aimed at investigating the chromium coating effect on the mechanical properties of Zr1Nb fuel claddings in the case of a tensile fracture in longitudinal and transverse directions at temperatures of 20 and 350 °С. Tests were carried out using the samples of a similar shape, namely, with an equal test portion length that is important for comparison of results. The obtained results have shown that at a test temperature of 20 °С the mechanical properties of initial samples are higher in the longitudinal direction than in the transverse direction. The ductility is slightly higher at T = 350 °С in the longitudinal direction, and σ0.2 and σв are practically equal. The preliminary deformation of ring samples increases their ductility from 23 to 34% independently on the test temperature. Deposition of the chromium coatings on the samples leads to the slight increase of mechanical properties in the transverse direction and decrease of σ0.2 with unchanged σв and δ% in the longitudinal direction at the room test temperature, and at 350 °С it practically do not change the properties of coated samples in both the directions except the ring sample ductility decrease.

2012 ◽  
Vol 217-219 ◽  
pp. 2381-2387
Author(s):  
Doru Romulus Pascu ◽  
Radu Alexandru Roşu ◽  
Iuliana Duma ◽  
Horia Daşcău

Non-alloyed P355NH steel according to EN 10028-3:2003 belongs to a group of fine-grained steels for pressure vessels being used in welded construction at decompression chamber for divers. Values of the chemical, structural and mechanical characteristics and steel toughness experimentally determined fit the analyzed steel in P355NH steel group according to EN 10028-3:2003. The toughness of the analyzed steel at the test temperature of -30°C is characterized by high values of fracture energy KV in longitudinal direction between 48 and 86 J and on transverse direction between 17 and 34J. Steel toughness at the test temperature of -30°C required by ABS standard (in Section 4/5.3 and Table 1) provides for breaking energy KV of min. 35J, with ductile fracture surfaces, value that is not respected at some lots of the three batches (A, B, C) of steel. Finally, based on the direct correlation established between HV10 hardness of the fine structure and the toughness it was made a selection of the lots of non-alloy steel P355NH which correspond to ABS norm for welded construction of the decompression chamber for divers


2021 ◽  
Vol 6 (3) ◽  
pp. 175-181
Author(s):  
R. B. Lysenko ◽  
◽  
V. I. Lіakhovskyi ◽  
V. R. Lysenko

The purpose of the study was to investigate the changes in the mechanical properties of the anterior abdominal wall at maximum functional loads. Materials and methods. The study was conducted on 112 volunteers aged 18 to 49 years old who were examined and treated in the surgical department of the Medical Diagnostic and Treatment Center "Medion" Poltava for the period from June 2020 to May 2021. There were 60 women (53.6 %), and 52 (46.4%) men. Volunteers were divided into 2 groups: the main group (n=58), which underwent the analysis of movement and deformation changes of the anterior abdominal wall during maximal abdominal inflation during the examination, and the control group (n=54), which were operated laparoscopically due to the schedule. Results and discussion. The results of the study showed the following changes in the mechanical properties of the tissues of the anterior abdominal wall: the average deformation in the longitudinal direction was 6% in the main group and 12% in the control one; deformations in the transverse direction were 3% in the main group and 8% in the control group; deformation in the longitudinal direction exceeded the deformation in the transverse by 38-54% (on average by 46%); the area of the anterior abdominal wall in the main group increased by 10%, and in the control one – by 22% (on average by 16%). During the studies, the anterior abdominal wall underwent greater stresses in the transverse orientation than in the longitudinal one (anisotropy coefficient ~2). The Young's modulus of anterior abdominal wall in the sagittal plane is defined as 23.5±2.6 kPa, while in the transverse – 42.5±7.0 kPa. The mechanical properties of human anterior abdominal wall tissues differed along and across the white line of the abdomen: the modulus of elasticity of anterior abdominal wall tissues, with the same force of impact, in the longitudinal direction is less than the transverse average of 44% (p >0.05). That is, the longitudinal stiffness of the anterior abdominal wall is lower than the transverse one. The maximum strength of the anterior abdominal wall is across the white line of the abdomen, and the greatest elasticity – along. The anterior abdominal wall in women showed increased elasticity compared to men, while the stiffness of the anterior abdominal wall tissue in men in both directions was statistically significantly higher than in women (p >0.05). Conclusion. Reconstruction of the spatial distribution of the mechanical properties of anterior abdominal wall tissues according to the nature of their deformation at maximum functional loads provides an additional opportunity to assess the biomechanics of anterior abdominal wall. The mechanical properties of the musculo-aponeurotic structures of anterior abdominal wall in humans differ in the longitudinal and transverse directions. They have the greatest elasticity in the longitudinal direction, and the maximum rigidity and strength in the transverse direction. The strength of the anterior abdominal wall tissue in men is higher, and the elasticity is less than in women. Changes in the mechanical anisotropic characteristics of anterior abdominal wall tissues at maximum functional loads should be taken into account when performing the anterior abdominal wall alloplasty technique


2007 ◽  
Vol 80 (5) ◽  
pp. 809-819 ◽  
Author(s):  
C. V. Marykutty ◽  
G. Mathew ◽  
Sabu Thomas

Abstract The concept of double networks, which impart chain orientation to elastomers, is a rather new idea. Double networks were induced in natural rubber vulcanizates cured with different accelerator systems. Double networked natural rubber with different extensions cured with N-cyclohexyl benzothiazyl sulphenamide (CBS) and 1-phenyl 5-ortho -tolyl 2,4 dithiobiuret was studied and the effect of extension on the mechanical properties and swelling was analyzed. The extent of chain orientation was analyzed through anisotropic swelling studies. The modulus, tensile strength and tear strength showed an increase with increased residual extension ratio. The effect was more predominant in the longitudinal direction than in the transverse direction. The ultimate tensile elongation showed a slight deterioration. It was revealed that the formation of double networks with higher residual extension ratios restricted the entry of the solvent. Based on the studies it was concluded that residual extension has a profound effect in determining the final properties of vulcanizates.


2007 ◽  
Vol 334-335 ◽  
pp. 829-832
Author(s):  
Joon Hyung Byun ◽  
Kyeong Sik Min ◽  
Yeun Ho Yu ◽  
Moon Kwang Um ◽  
Sang Kwan Lee

This study describes a method of good dispersion and alignment of VGCFs, and examines the effect of nanofiber content on the mechanical properties of nanocomposites. The dispersion of nanofibers was carried out by solution blending, mechanical mixing, and sonication. Levels of 4% – 31% volume content of VGCFs were mixed with polypropylene (PP) powder, and then were melt-mixed using a twin-screw extruder. For the further alignment of fibers, extruded rods were stacked in the mold cavity for the compression molding. In the case of 31% volume content, tensile modulus and strength improved by 100% and 40%, and the flexural modulus and strength increased by 120% and 25%, respectively. The shear modulus showed 65% increase, but the strength dropped sharply by 40%. In the transverse direction, the tensile, flexural, and shear strength decreased as more fibers were added. The matrix modification by maleic anhydride (MAPP) increased the tensile and flexural properties of VGCF/PP by 20% - 30% in the longitudinal direction, and 40% - 250% increase in the transverse direction. The fiber surface treatment by plasma improved tensile and flexural properties of untreated VGCF/PP (18 % vol) composites by 10% - 30% in the longitudinal direction, but strength in the transverse direction decreased by 30% - 40%.


2020 ◽  
Vol 24 (5) ◽  
pp. 1007-1018
Author(s):  
Tatiana Osipok ◽  
◽  
Semen Zaides ◽  

The purpose of the article is to establish experimentally the effect of material inhomogeneity on the characteristics of strength ( σ в, σ 0.2) and plasticity (δ) on example of a rolled steel sheet. Uniaxial tensile testing was carried out on flat samples of hot-rolled sheet made of St3 alloy cut in three directions relative to rolling: along, across and at the angle of 450. The heterogeneity of structure was established by studying the fracture surface of the destroyed samples after tensile testing. A metallographic research and micromechanical testing (measurement of microhardness) of sections parallel to the fracture surface were carried out as well. The uniaxial tensile testing of flat samples resulted in obtaining the values of the characteristics of strength ( σ в, σ 0.2) and plasticity (δ). The analysis of fracture patterns, microstructure and microhardness values of the material allowed to reveal the structural heterogeneity caused by the presence of fibrousness and a banded ferrite-pearlite structure oriented along the deformation direction. The formation reason of the latter was the presence of oriented non-metallic inclusions - elongated plastic sulfides. The study determined that the material under investigation features the anisotropy of mechanical properties and structural heterogeneity. The values of the ultimate strength ( σ в) and yield strength ( σ 0.2) decrease from the longitudinal direction to the transverse direction (relative to the rolling direction) and vice versa (from the transverse to longitudinal direction) in the first case probably due to the influence of non-metallic inclusions (plastic sulfides) and, as a result, the banded ferrite-pearlite structure; in the second case due to the influence of fiber direction. The values of the relative elongation (δ) decrease from the longitudinal direction to the direction at an angle of 450 and then increase to the transverse direction as a result of different hardening of the material during plastic deformation. This is proved by the obtained microhardness values of the investigated sections and the values of the maximum applied loads during the tensile test. The obtained values are obviously the result of the influence of fiber orientation relative to the existing maximum tensile stresses.


2017 ◽  
Vol 60 (3) ◽  
pp. 581-590 ◽  
Author(s):  
Bo Liu ◽  
A. Bulent Koc

Abstract. The mechanical properties of energy crops in the longitudinal and transverse directions are necessary for modeling and simulation of biomass stems. Modeling of biomass stems would help in analyzing the interactions between processing equipment and biomass material before building physical systems. While some of the mechanical properties of switchgrass and miscanthus stems are available in the literature, these properties are not complete for modeling and simulation of these materials. Therefore, the objective of this research was to determine the mechanical properties of switchgrass and miscanthus stems by using compressive, tensile, and shearing tests in the longitudinal and transverse directions. Tensile, compressive, and shear strengths and modulus of elasticity of switchgrass and miscanthus tended to decrease with decreasing stem diameter in both the longitudinal and transverse directions. Tensile and compressive strengths of the first internode of switchgrass were 178.0 and 27.3 MPa in the longitudinal direction and 0.7 and 4.1 MPa in the transverse direction. Shear strength for the first internode of switchgrass was 2.2 and 21.1 MPa in the longitudinal and transverse directions. Tensile and compressive strengths of the first internode of miscanthus were 373.1 and 56.9 MPa in the longitudinal direction and 1.8 and 6.3 MPa in the transverse direction. Shear strength for the first internode of miscanthus was 94.4 and 8.7 MPa in the transverse and longitudinal directions. The experimental data collected in this research would be useful for the development of simulation models for investigating the interactions between shearing tools and energy crops and in designing harvest and particle reduction equipment. Further research would be useful for determining the effects of moisture content, growth conditions, and maturity stage on the mechanical properties of these crops. Keywords: Biofuel, Compressive strength, Miscanthus, Shear strength, Switchgrass, Tensile strength.


Alloy Digest ◽  
1983 ◽  
Vol 32 (3) ◽  

Abstract AISI 1141 is a resulfurized carbon steel containing nominally 1.50% manganese and 0.08-0.13% sulfur to give it free-machining characteristics. It has relatively low hardenability. Its ductility and toughness are fairly good in the longitudinal direction but tend to be low in the transverse direction. It is highly recommended for high-production automatic-machine products. Among its many uses are screws, bolts, ball joints, spindles and light-duty gears. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-93. Producer or source: Carbon steel mills.


2021 ◽  
Vol 2 (2) ◽  
pp. 419-430
Author(s):  
Ankur Bajpai ◽  
James R. Davidson ◽  
Colin Robert

The tensile fracture mechanics and thermo-mechanical properties of mixtures composed of two kinds of epoxy resins of different chemical structures and functional groups were studied. The base resin was a bi-functional epoxy resin based on diglycidyl ether of bisphenol-A (DGEBA) and the other resins were (a) distilled triglycidylether of meta-amino phenol (b) 1, 6–naphthalene di epoxy and (c) fluorene di epoxy. This research shows that a small number of multifunctional epoxy systems, both di- and tri-functional, can significantly increase tensile strength (14%) over neat DGEBA while having no negative impact on other mechanical properties including glass transition temperature and elastic modulus. In fact, when compared to unmodified DGEBA, the tri-functional epoxy shows a slight increase (5%) in glass transition temperature at 10 wt.% concentration. The enhanced crosslinking of DGEBA (90 wt.%)/distilled triglycidylether of meta-amino phenol (10 wt.%) blends may be the possible reason for the improved glass transition. Finally, the influence of strain rate, temperature and moisture were investigated for both the neat DGEBA and the best performing modified system. The neat DGEBA was steadily outperformed by its modified counterpart in every condition.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 875
Author(s):  
Hao Tian ◽  
Jianchao He ◽  
Jinbao Hou ◽  
Yanlong Lv

TiB crystal whiskers (TiBw) can be synthesized in situ in Ti alloy matrix through powder metallurgy for the preparation of a new type of ceramic fiber-reinforced Ti matrix composite (TMC) TiBw/Ti-6Al-4V. In the TiBw/Ti-6Al-4V TMC, the reinforced phase/matrix interface is clean and has superior comprehensive mechanical properties, but its machinability is degraded. Hence, the bonding of reliable materials is important. To further optimize the TiBw/Ti-6Al-4V brazing technology and determine the relationship between the microstructure and tensile property of the brazed joint, results demonstrate that the elements of brazing filler metal are under sufficient and uniform diffusion, the microstructure is the typical Widmanstätten structure, and fine granular compounds in β phase are observed. The average tensile strength of the brazing specimen is 998 MPa under room temperature, which is 97.3% of that of the base metal. During the high-temperature (400 °C) tensile process, a fracture occurred at the base metal of the highest tensile test specimen with strength reaching 689 MPa, and the tensile fracture involved a combination of intergranular and transgranular modes at both room temperature and 400 °C. The fracture surface has dimples, secondary cracks are generated by the fracture of TiB whiskers, and large holes form when whole TiB whiskers are removed. The proposed algorithm provides evidence for promoting the application of TiBw/Ti-6Al-4V TMCs in practical production.


Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Xu Xu ◽  
Zeping Zhang ◽  
Wenjuan Yao

Graphene and graphene oxide (GO) usually have grain boundaries (GBs) in the process of synthesis and preparation. Here, we “attach” GBs into GO, a new molecular configuration i.e., polycrystalline graphene oxide (PGO) is proposed. This paper aims to provide an insight into the stability and mechanical properties of PGO by using the molecular dynamics method. For this purpose, the “bottom-up” multi-structure-spatial design performance of PGO and the physical mechanism associated with the spatial structure in mixed dimensions (combination of sp2 and sp3) were studied. Also, the effect of defect coupling (GBs and functional groups) on the mechanical properties was revealed. Our results demonstrate that the existence of the GBs reduces the mechanical properties of PGO and show an “induction” role during the tensile fracture process. The presence of functional groups converts in-plane sp2 carbon atoms into out-of-plane sp3 hybrid carbons, causing uneven stress distribution. Moreover, the mechanical characteristics of PGO are very sensitive to the oxygen content of functional groups, which decrease with the increase of oxygen content. The weakening degree of epoxy groups is slightly greater than that of hydroxyl groups. Finally, we find that the mechanical properties of PGO will fall to the lowest values due to the defect coupling amplification mechanism when the functional groups are distributed at GBs.


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