Effect of non-zero mean stress bending-torsion fatigue on fracture surface parameters of 34CrNiMo6 steel notched bars

Modern methods of testing materials require the use of the latest technologies and combining measurement and calculation methods. It is important to find a quantitative way of describing, among other things, the failures so that it can help to design with high accuracy. This paper studies loading orientations on crack shape and fracture surface changes. The advantage of the entire fracture surface method is simplicity and applicability in studies on other materials, shapes and loadings. A higher values of fracture surface parameters (Sx, Vx) was observed in failure specimens with lower σ/τ (B/T) ratios. It has been observed that largest crack lengths with a small number of cycles occur for loading combinations different then B=T. As well as analyzed surface parameters Sx, Vx, are higher for larger number of cycles to crack initiation (Ni) values

Effect of non-zero mean stress bending-torsion fatigue on fracture surface parameters of 34CrNiMo6 steel notched bars

Modern methods of testing materials require the use of the latest technologies and combining meas-urement and calculation methods. It is important to find a quantitative way of describing, among other things, the failures so that it can help to design with high accuracy. This paper studies loading orien-tations on crack shape and fracture surface changes. The advantage of the entire fracture surface method is simplicity and applicability in studies on other materials, shapes and loadings. A higher values of fracture surface parameters (Sx, Vx) was observed in failure specimens with lower σ/τ (B/T) ratios. It has been observed that largest crack lengths with a small number of cycles occur for loading combinations different then B=T. As well as analyzed surface parameters Sx, Vx, are higher for larger number of cycles to crack initiation (Ni) values

Fracture Surface Behavior of 34CrNiMo6 High-Strength Steel Bars with Blind Holes under Bending-Torsion Fatigue

The present study evaluates the fracture surface response of fatigued 34CrNiMo6 steel bars with transverse blind holes subjected to bending with torsion loading. The analysis of the geometric product specification was performed by means of height parameters Sx, functional volume parameters Vx, and fractal dimension Df. Surface topography measurements were carried out using an optical profilometer with focus variation technology. The experimental results show that the doubling the bending to torsion moment ratio B/T from B/T = 1 to B/T = 2, maintaining the same normal stress amplitude, greatly reduces both Sa, Vv as well as the fractal dimension Df of the analyzed specimen fractures by 32.1%, 29.8%, and 16.0%, respectively. However, as expected, a two-fold increase in the B/T ratio, maintaining the same normal stress amplitude, resulted in a larger number of cycles to fatigue crack initiation, Ni, which can be explained by the lower shear stress level. These experiments prove that parameters Sx, Vx, Df are smaller for larger Ni values, which is an important finding. In addition, it was found a high consistency of surface topography measurements for the two sides of the broken specimens. The proposed methodology is both reliable and applicable for other engineering applications involving different geometries and loading conditions. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Production potential of biodiesel, methane and electricity in the largest steamed rice industry in Rio Grande do Sul, Brazil: case study

The potential for energy production from effluents and husks generated in grain processing in the rice parboiling industries in Brazil is capable of promoting energy self-sufficiency in the sector, through the production and use of syngas and biogas. However, the production of methane from residues of the rice parboiling industries is still little explored by academic studies, in general studies on the potential of methane production by this same type of effluent are found in the south of the country, however, the same is not true for the production of biodiesel from rice bran oil. The objective of this study was to determine the production potential of biodiesel, methane and electric energy of the largest parboiled rice industry in Rio Grande do Sul, located in the southern region of the country. According to this study, the rice parboiling industry located in Rio Grande do Sul, Brazil, has a production potential of 1.2-10² m³ /day of biodiesel, 2.93-10 Nm³ /day of methane and 1.89-10⁴ kWh/day of electricity. Despite being a significant and high potential, which may reduce the financial expenses of the industry regarding the purchase of energy from concessionaires, it is not able to promote its energy self-sufficiency. At the same time, it would be necessary to add the energy production potential of the rice husk gasification syngas highlighted in other studiem

Production potential of biodiesel, methane and electricity in the largest steamed rice industry in Rio Grande do Sul, Brazil: case study

The potential for energy production from effluents and husks generated in grain processing in the rice parboiling industries in Brazil is capable of promoting energy self-sufficiency in the sector, through the production and use of syngas and biogas. However, the production of methane from residues of the rice parboiling industries is still little explored by academic studies, in general studies on the potential of methane production by this same type of effluent are found in the south of the country, however, the same is not true for the production of biodiesel from rice bran oil. The objective of this study was to determine the production potential of biodiesel, methane and electric energy of the largest parboiled rice industry in Rio Grande do Sul, located in the southern region of the country. According to this study, the rice parboiling industry located in Rio Grande do Sul, Brazil, has a production potential of 1.2-10² m³ /day of biodiesel, 2.93-10 Nm³ /day of methane and 1.89-10⁴ kWh/day of electricity. Despite being a significant and high potential, which may reduce the financial expenses of the industry regarding the purchase of energy from concessionaires, it is not able to promote its energy self-sufficiency. At the same time, it would be necessary to add the energy production potential of the rice husk gasification syngas highlighted in other studiem