Statistical analysis of different mathematical models for stress-strain curves of AISI 321 stainless steel

This paper presents statistical analysis of data obtained by uniaxial tensile testing of AISI 321 stainless steel. This data is required as material input in numerical software, such as Abaqus, Ansys, MSC Marc, Nastran, etc. This data can be provided in the software as a set of points (piecewise linear model) that is cumbersome to enter, or it can be provided as a mathematical model, in the case of which the Finite Element Method (FEM) software calculates desired points directly from the mathematical model. Various mathematical models can be used to approximate tensile test data depending on the material loading state (linear, elasto-plastic, plastic). In this paper, the same uniaxial test data is analyzed, and curve fitting parameters are shown for each mathematical model

Statistical analysis of different mathematical models for stress-strain curves of AISI 321 stainless steel

This paper presents statistical analysis of data obtained by uniaxial tensile testing of AISI 321 stainless steel. This data is required as material input in numerical software, such as Abaqus, Ansys, MSC Marc, Nastran, etc. This data can be provided in the software as a set of points (piecewise linear model) that is cumbersome to enter, or it can be provided as a mathematical model, in the case of which the Finite Element Method (FEM) software calculates desired points directly from the mathematical model. Various mathematical models can be used to approximate tensile test data depending on the material loading state (linear, elasto-plastic, plastic). In this paper, the same uniaxial test data is analyzed, and curve fitting parameters are shown for each mathematical model

Compressive stresses of mould mixture

The source of compressive stresses lies in the structure of quartz sand. By reaching the critical temperature (from 560 to 580 °C), the quartz sand grains increase volume. The increase in volume causes the movement of surrounding grains of sand. In this paper, it is shown by the dilatometric investigations of different granulometric compositions of quartz sands how the granulometric composition affects the size of the mould dilatation caused by heating during pouring of the melt

Influence of process parameters on castability at full mold casting

This paper examines the effect of the temperature of pouring the melt, the density of the model of foamed polystyrene and the casting with or without a vent on castability. The testing was carried out in accordance with the experiment plan 23 i.e. during testing the value of the parameters of influence was changed at two levels: the melt pouring temperature of 640 °C and 600 °C, casting with or without a vent, and the density of foamed polystyrene model of 15 kg/m3 and 30 kg/m3

Epistasis and genotype-by-environment interaction of grain protein content in durum wheat

Parental, F1 , F 2 , BC 1 and BC 2 generations of four crosses involving four cultivars of durum wheat (Triticum durum Desf.) were evaluated at two sites in Tunisia. A three-parameter model was found inadequate for all cases except crosses Chili x Cocorit 71 at site Sidi Thabet and Inrat 69 x Karim at both sites. In most cases a digenic epistatic model was sufficient to explain variation in generation means. Dominance effects (h) and additive x additive epistasis (i) (when significant) were more important than additive (d) effects and other epistatic components. Considering the genotype-by-environment interaction, the non-interactive model (m, d, h, e) was found adequate. Additive variance was higher than environmental variance in three crosses at both sites. The estimated values of narrow-sense heritability were dependent upon the cross and the sites and were 0%-85%. The results indicate that appropriate choice of environment and selection in later generations would increase grain protein content in durum wheat

Strategic crossing of biomass and harvest index—source and sink—achieves genetic gains in wheat

To accelerate genetic gains in breeding, physiological trait (PT) characterization of candidate parents can help make more strategic crosses, increasing the probability of accumulating favorable alleles compared to crossing relatively uncharacterized lines. In this study, crosses were designed to complement “source” with “sink” traits, where at least one parent was selected for favorable expression of biomass and/or radiation use efficiency—source—and the other for sink-related traits like harvest-index, kernel weight and grains per spike. Female parents were selected from among genetic resources—including landraces and products of wide-crossing (i.e. synthetic wheat)—that had been evaluated in Mexico at high yield potential or under heat stress, while elite lines were used as males. Progeny of crosses were advanced to the F4 generation within Mexico, and F4-derived F5 and F6 generations were yield tested to populate four international nurseries, targeted to high yield environments (2nd and 3rd WYCYT) for yield potential, and heat stressed environments (2nd and 4th SATYN) for climate resilience, respectively. Each nursery was grown as multi-location yield trials. Genetic gains were achieved in both temperate and hot environments, with most new PT-derived lines expressing superior yield and biomass compared to local checks at almost all international sites. Furthermore, the tendency across all four nurseries indicated either the superiority of the best new PT lines compared with the CIMMYT elite checks, or the superiority of all new PT lines as a group compared with all checks, and in some cases, both. Results support—in a realistic breeding context—the hypothesis that yield and radiation use efficiency can be increased by improving source:sink balance, and validate the feasibility of incorporating exotic germplasm into mainstream breeding efforts to accelerate genetic gains for yield potential and climate resilience