scholarly journals Force parameters of metal deformation during sheet drawing

2020 ◽  
Vol 16 (6) ◽  
pp. 493-503
Author(s):  
Yury A. Morozov
Keyword(s):  
Stress State ◽  
Strain State ◽  
Sheet Material ◽  
Forming Force ◽  
High Quality ◽  
State Process ◽  
The Matrix ◽  
Metal Deformation ◽  
Volumetric Stress ◽  
Steady State Process

The aim of the work. The effect of the curvature of the rounding of torus surfaces during the formation of a cylindrical product (glass) is investigated, taking into account the plastic thinning of the deformable material at the end edges of the matrix and pressing punch. Methods. The existing scheme for determining the power parameters of sheet drawing is analyzed, based on the assumption of the implementation of some abstract stress state in the material; mainly conditional tensile strength. At the same time, the possibility of forming the product without destruction determines the obvious overestimation of the stress level. A mathematical model of the volumetric stress state of the metal is being developed, which makes it possible to assess the deformation and stress state during the formation of a cold-drawn product, i. e. the folding of the sheet blank along the end radius of the rounding of the pressing punch and the steady-state process of drawing the blank into the deformation zone with successive bending/straightening of the material along the edge of the matrix are considered. The level of radial stresses during folding and stretching of sheet material is estimated, taking into account its strain hardening and thinning, which determine the forming force. The obtained results will make it possible to simulate the stress-strain state of the metal during the development of sheet drawing technology: to establish the amount of thinning, to estimate the level of radial stresses in the formation of rounding of torus surfaces along the end edges of the matrix and the pressing punch, as well as to determine the power parameters of the formation, which will prevent the destruction of the pulled part, guaranteeing obtaining high-quality products and more accurately choosing the deforming equipment.

Cosserat Modeling of Size Effects in Crystalline Solids

2000 ◽  
Vol 653 ◽  
Author(s):  
Samuel Forest
Keyword(s):  
Stress State ◽  
Size Effects ◽  
Elastic Inclusion ◽  
Characteristic Size ◽  
Infinite Matrix ◽  
Crystalline Solids ◽  
Generalized Continua ◽  
Absolute Size ◽  
Kink Bands ◽  
The Matrix

AbstractThe mechanics of generalized continua provides an efficient way of introducing intrinsic length scales into continuum models of materials. A Cosserat framework is presented here to descrine the mechanical behavior of crystalline solids. The first application deals with the problem of the stress field at a crak tip in Cosserat single crystals. It is shown that the strain localization patterns developping at the crack tip differ from the classical picture : the Cosserat continuum acts as a bifurcation mode selector, whereby kink bands arising in the classical framework disappear in generalized single crystal plasticity. The problem of a Cosserat elastic inclusion embedded in an infinite matrix is then considered to show that the stress state inside the inclusion depends on its absolute size lc. Two saturation regimes are observed : when the size R of the inclusion is much larger than a characteristic size of the medium, the classical Eshelby solution is recovered. When R is much small than the inclusion, a much higher stress is reached (for an inclusion stiffer than the matrix) that does not depend on the size any more. There is a transition regime for which the stress state is not homogeneous inside the inclusion. Similar regimes are obtained in the study of grain size effects in polycrystalline aggregates of Cosserat grains.

Effects of temperature and organic loading on the performance of upflow anaerobic sludge blanket reactors

1995 ◽  
Vol 22 (1) ◽  
pp. 143-149 ◽  
Author(s):  
Shannon Grant ◽  
Kwan-Chow Lin
Keyword(s):  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Organic Loading ◽  
Reactor Kinetics ◽  
State Process ◽  
Kinetic Coefficients ◽  
Reactor Temperature ◽  
Effects Of Temperature ◽  
Anaerobic Sludge Blanket ◽  
Steady State Process

A study investigating the effects of temperature and organic loading on the performance of upflow anaerobic sludge blanket reactors was carried out in the laboratory. Laboratory-scale reactors of 3.2 L volume were semicontinuously fed a synthetic substrate consisting of beef consommé and macro- and micro-nutrient compounds. Temperatures ranged from 10 to 42 °C; organic loadings ranged from 2.0 to 30 kg COD/(m3∙d). Steady-state process kinetics and efficiencies were evaluated for the various conditions. Based on the assumption that upflow anaerobic sludge blanket reactor kinetics in the temperature range of 10–30 °C could be approximated by Monod and modified Arrhenius equation relationships, effluent SCOD concentrations and removals were used to determine the maximum rate of substrate utilization, the half-velocity constant, and the temperature coefficient. A design and operating chart was constructed based on the kinetic coefficients determined from the experimental data. Key words: upflow anaerobic sludge blanket reactor, temperature, loading, performance, kinetics.

Applying sustainability indicators in the analysis and segmentation of tourist demand - implications for marine visitor experiences on the Tremiti Islands, Italy.

2021 ◽  
pp. 192-204
Author(s):  
Nicolaia Iaffaldano ◽  
Sonia Ferrari
Keyword(s):  
National Park ◽  
Marine Reserve ◽  
Sustainability Indicators ◽  
High Quality ◽  
Visitor Experiences ◽  
Different Types ◽  
The Matrix ◽  
Crucial Information ◽  
Tourist Demand ◽  
Questionnaire Research

Abstract This chapter presents the findings of qualitative questionnaire research carried out in the Tremiti Islands Marine Reserve, which is part of Gargano National Park, Italy. The study have identified different segments of tourists visiting Tremiti by means of the model proposed by Arnegger et al. (2010), using the matrix suggested in the model. The model was used to understand and categorize visitor characteristics, their expectations and levels of satisfaction, and the strengths and weaknesses of local offerings. This is crucial information for the managers of the marine reserve who require thorough knowledge of the different types of visitors to adapt to the needs, expectations and preferences of the visitors in order to offer high-quality services and memorable experiences.

Sign in / Sign up

Export Citation Format

Share Document