Stress-Strain-Analysis of Grapevine Pruning with Powered and Non-Powered Hand Tools

2000 ◽  
Vol 44 (22) ◽  
pp. 639-642 ◽  
Author(s):  
Jurij Wakula ◽  
Thomas Beckmann ◽  
Michael Hett ◽  
Kurt Landau
Keyword(s):  
Strain Analysis ◽  
Stress Factors ◽  
Climate Condition ◽  
Hand Tools ◽  
Stress Strain ◽  
Repetitive Movements ◽  
Power Tools ◽  
Power Hand Tools ◽  
External Forces

Non-power and power cutting hand tools are mainly used every day in vineyards for grapevines pruning during 5 months (November - March). The grapevines pruning with the help of non-power tools is very stressful for wine growers. Repetitive movements combined with external forces in finger-hand-wrist-system, extreme positions in arm-shoulder-system, climate condition are some of the stress factors. Grapevines pruning with 5 manual prunes produced by 3 different manufacture and 2 power hand tools (electrically and pneumatically) were analysed. The results reveal that grapevines pruning with pneumatic and electric prunes is up to 30% more effective (according to productivity) than cutting with non-powered hand tools. At the same time is grapevines cutting with power tools more stressful as with non-powered one.

Ergonomic analysis of grapevine pruning and wine harvesting to define work and hand tools design requirements

2000 ◽  
Vol 2 (3) ◽  
pp. 151-161
Author(s):  
Jurij Wakula ◽  
Thomas Beckmann ◽  
Michael Hett ◽  
Kurt Landau
Keyword(s):  
Cutting Tools ◽  
Strain Analysis ◽  
Upper Limbs ◽  
Cumulative Trauma ◽  
Hand Tools ◽  
Stress Strain ◽  
High Incidence ◽  
Design Requirements ◽  
Ergonomic Analysis ◽  
Trauma Disorders

Knowledge of the stress-strain analysis while grapevines pruning and wine harvesting in vineyards will make a significant contribution towards reducing the risk of cumulative trauma disorders (CTD) in the upper limbs of vineyard workers. The stress-strain analysis in field and laboratory studies show that pruning grapevines and wine harvesting involves a combination of dynamic and sensorimotoric work, and also a high incidence of ergonomically undesirable postures of the trunk, the upper limbs and the head irrespective of cutting tools used. The information obtained can be applied in the ergonomic redesign of pruning tasks and pruning tools to reduce incidence of trauma.

scholarly journals Direct method of load simulation in hull strength analysis of catamaran

2020 ◽  
Vol S-I (2) ◽  
pp. 230-236
Author(s):  
R. Chistyakov ◽  
◽  
P. Mudrik ◽  
Keyword(s):  
Direct Method ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Strength Analysis ◽  
Ship Motions ◽  
Regular Waves ◽  
Stress Strain ◽  
Internal Forces ◽  
External Forces ◽  
Force Calculation

This paper discusses three-dimensional formulation for the problem of external forces acting on catamaran hull, as well as performs stress-strain state analysis of the structures affected by the loads thus calculated. The purpose of this study was to develop a modern methodology for joint solution to the first and the second problem of naval structural mechanics based on panelpotential and finite-element models in three-dimensional formulation for the conditions of still water and regular waves. The study discusses various formulations of the problem and various methods of external force calculation. External load is estimated in two formulations: static (based on hydrostatic methods) and stationary dynamic (based on the linear theory of ship motions). Also, external forces and their respective stresses were estimated as per the procedure of the classification society. The case study of a catamaran illustrates the process of load calculation and stress-strain analysis, giving the results for various external forces, with their assessment and analysis of internal forces and displacements induced by them. The study yielded rather handy technique for stress-strain analysis of catamaran hull in 3D formulation, including spatial static trimming in still water and in waves of given profile, as well as calculation of displacement amplitudes in regular waves, calculation of phase pressure fields and accelerations on catamaran hull, with further export of calculated external loads to FE analysis software for stressstrain investigation of structurally similar model needed to understand how conservative this model is.

Delamination in the scoring and folding of paperboard

TAPPI Journal ◽  
2012 ◽  
Vol 11 (1) ◽  
pp. 61-66 ◽  
Author(s):  
DOEUNG D. CHOI ◽  
SERGIY A. LAVRYKOV ◽  
BANDARU V. RAMARAO
Keyword(s):  
Finite Element ◽  
Plane Deformation ◽  
Strain Analysis ◽  
Local Strain ◽  
Uniaxial Stress ◽  
Material Model ◽  
Element Model ◽  
Plastic Behavior ◽  
Stress Strain ◽  
Strain Fields

Delamination between layers occurs during the creasing and subsequent folding of paperboard. Delamination is necessary to provide some stiffness properties, but excessive or uncontrolled delamination can weaken the fold, and therefore needs to be controlled. An understanding of the mechanics of delamination is predicated upon the availability of reliable and properly calibrated simulation tools to predict experimental observations. This paper describes a finite element simulation of paper mechanics applied to the scoring and folding of multi-ply carton board. Our goal was to provide an understanding of the mechanics of these operations and the proper models of elastic and plastic behavior of the material that enable us to simulate the deformation and delamination behavior. Our material model accounted for plasticity and sheet anisotropy in the in-plane and z-direction (ZD) dimensions. We used different ZD stress-strain curves during loading and unloading. Material parameters for in-plane deformation were obtained by fitting uniaxial stress-strain data to Ramberg-Osgood plasticity models and the ZD deformation was modeled using a modified power law. Two-dimensional strain fields resulting from loading board typical of a scoring operation were calculated. The strain field was symmetric in the initial stages, but increasing deformation led to asymmetry and heterogeneity. These regions were precursors to delamination and failure. Delamination of the layers occurred in regions of significant shear strain and resulted primarily from the development of large plastic strains. The model predictions were confirmed by experimental observation of the local strain fields using visual microscopy and linear image strain analysis. The finite element model predicted sheet delamination matching the patterns and effects that were observed in experiments.

Stress-Strain Analysis and Simulation for Estimation of Cutting Forces on the Skin

2015 ◽  
Vol 9 (6) ◽  
pp. 583
Author(s):  
Dario German Buitrago ◽  
Luis Carlos Ruíz ◽  
Olga Lucia Ramos
Keyword(s):  
Cutting Forces ◽  
Strain Analysis ◽  
Stress Strain

scholarly journals Horizontal Movement of Fast Ice in the North Water Area

1977 ◽  
Vol 19 (81) ◽  
pp. 547-554 ◽  
Author(s):  
Hajime Ito ◽  
Fritz Müller
Keyword(s):  
Sea Ice ◽  
Water Area ◽  
Physical Characteristics ◽  
Stress Strain ◽  
Horizontal Movement ◽  
The North ◽  
North Water ◽  
Fast Ice ◽  
External Forces

AbstractThe understanding of the horizontal movement of fast ice is important for applied sea-ice mechanics. A case study, carried out in conjunction with a polynya known as North Water, is presented in this paper. The displacements of the fast-ire arches which separate the polynya from the surrounding ice-covered sea, were measured and found to be small. It is, therefore, confirmed that these arches prevent the influx of large quantities of sea ice into the polynya. The results are then explained in terms of the external forces (wind and current), the stress- strain situations and some physical characteristics (temperature and thickness) which were measured simultaneously.

Stress Analysis of Pipeline Subjected to Differential Frost Heave

2013 ◽  
Author(s):  
Yan Di ◽  
Jian Shuai ◽  
Lingzhen Kong ◽  
Xiayi Zhou
Keyword(s):  
Strain Analysis ◽  
Element Model ◽  
Frozen Soil ◽  
Computational Method ◽  
Frost Heave ◽  
Safe Operation ◽  
Stress Strain ◽  
Segregation Potential ◽  
Differential Frost Heave ◽  
Design Construction

Frost heave must be considered in cases where pipelines are laid in permafrost in order to protect the pipelines from overstress and to maintain the safe operation. In this paper, a finite element model for stress/strain analysis in a pipeline subjected to differential frost heave was presented, in which the amount of frost heave is calculated using a segregation potential model and considering creep effects of the frozen soil. In addition, a computational method for the temperature field around a pipeline was proposed so that the frozen depth and temperature variation gradient could be obtained. Using the procedure proposed in this paper, stress/strain can be calculated according to the temperature on the surface of soil and in a pipeline. The result shows the characteristics of deformation and loading of a pipeline subjected to differential frost heave. In general, the methods and results in this paper can provide a reference for the design, construction and operation of pipelines in permafrost areas.

Numerical Modeling and Analytical Investigation of Autofrettage Process on the Fluid End Module of Fracture Pumps

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Mahdi Kiani ◽  
Roger Walker ◽  
Saman Babaeidarabad
Keyword(s):  
Residual Stresses ◽  
Kinematic Hardening ◽  
Analytical Formula ◽  
Strain Analysis ◽  
Material Model ◽  
Analytical Investigation ◽  
Stress Strain ◽  
Element Analysis ◽  
Hardening Material ◽  
Strain Evolution

One of the most important components in the hydraulic fracturing is a type of positive-displacement-reciprocating-pumps known as a fracture pump. The fluid end module of the pump is prone to failure due to unconventional drilling impacts of the fracking. The basis of the fluid end module can be attributed to cross bores. Stress concentration locations appear at the bores intersections and as a result of cyclic pressures failures occur. Autofrettage is one of the common technologies to enhance the fatigue resistance of the fluid end module through imposing the compressive residual stresses. However, evaluating the stress–strain evolution during the autofrettage and approximating the residual stresses are vital factors. Fluid end module geometry is complex and there is no straightforward analytical solution for prediction of the residual stresses induced by autofrettage. Finite element analysis (FEA) can be applied to simulate the autofrettage and investigate the stress–strain evolution and residual stress fields. Therefore, a nonlinear kinematic hardening material model was developed and calibrated to simulate the autofrettage process on a typical commercial triplex fluid end module. Moreover, the results were compared to a linear kinematic hardening model and a 6–12% difference between two models was observed for compressive residual hoop stress at different cross bore corners. However, implementing nonlinear FEA for solving the complicated problems is computationally expensive and time-consuming. Thus, the comparison between nonlinear FEA and a proposed analytical formula based on the notch strain analysis for a cross bore was performed and the accuracy of the analytical model was evaluated.

Stress – Strain Analysis on ZnO Nanostructures Synthesized via Wet Chemistry Method

2015 ◽  
Vol 1112 ◽  
pp. 57-61 ◽  
Author(s):  
Amalia Sholehah ◽  
Akhmad Herman Yuwono
Keyword(s):  
Crystallite Size ◽  
Strain Analysis ◽  
Xrd Analysis ◽  
Heating Process ◽  
Zno Nanostructures ◽  
Stress Strain ◽  
Wet Chemistry ◽  
Chemistry Method ◽  
Hall Method ◽  
Scherrer Equation

In the present work, ZnO nanostructures were synthesized via wet chemistry method. The seeding solution was prepared from zinc nitrate tetrahydrate and hexamethylenetetramine. Prior to the heating process, the seeding solution was immersed in cold bath (0°C). XRD analysis had shown sharp peaks in diffractogram, indicating the high crystallinity of ZnO nanostructures. The crystallite size was determined using Scherrer equation and Williamson-Hall method. Other relevant parameters including stress, strain, and energy density were calculated using Williamson-Hall assuming UDM, UDSM, and UDEDM. The results had revealed that crystallite size calculated with Williamson-Hall method is more accurate than Scherrer equation.

A multiaxial stress-strain analysis for proportional cyclic loading

1993 ◽  
Vol 28 (2) ◽  
pp. 125-133 ◽  
Author(s):  
A Navarro ◽  
M W Brown ◽  
K J Miller
Keyword(s):  
Strain Analysis ◽  
Hysteresis Loops ◽  
Strain Curve ◽  
Cyclic Stress ◽  
Strain Hardening Exponent ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Flow Equations ◽  
Deformation Response ◽  
Tubular Specimens

A simplified treatment is presented for the analysis of tubular specimens subject to in-phase tension-torsion loads in the elasto-plastic regime. Use is made of a hardening function readily obtainable from the uniaxial cyclic stress-strain curve and hysteresis loops. Expressions are given for incremental as well as deformation theories of plasticity. The reversals of loading are modelled by referring the flow equations to the point of reversal and calculating distances from the point of reversal using a yield critertion. The method has been used to predict the deformation response of in-phase tests on an En15R steel, and comparisons with experimental data are provided. The material exhibited a non-Masing type behaviour. A power law rule is developed for predicting multiaxial cyclic response from uniaxial data by incorporating a hysteretic strain hardening exponent.

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