Studying the Normal Operation of Grain Harvesters within the Warranty Period

Introduction. Grain harvesters are used for no more than two months within a year. They must have maximum operating reliability, since even short downtime during the harvesting period result in large crop losses. The purpose of the study is to identify the causes of combine harvester failures within the warranty period. Materials and Methods. Identifying consequences of failures and ensuring the reliability of grain harvesters are based on an improved classification of failures. In the process of studying, there have been proposed the ways to solve the problem of combine harvester downtime based on the analysis of the time for grain harvester troubleshooting. The category of severity of failure consequences was taken into account. Results. Through monitoring in the period from 2018 to 2020, there were found failures of units and systems of grain harvesters with low reliability indexes within the warranty period. Most of the failures (59.2%) were found in Russian-manufactured combines, of which operational failures are 55.9%, structural failures – 26.7%, and production failures – 17.4%. The general patterns of changes in the average time for combine troubleshooting have been determined. A geometric model of a detail for the trouble-free operation of combines (header auger shaft) was created. The finite element analysis (ANSYS) was used to identify parts, which are subject to maximum workload. There have been identified units and parts, which fail to function within the warranty period, because of design and technological defects. Discussion and Conclusion. In order to reduce the time to find the consequences of failures, it is necessary to create a more extensive network of enterprises providing a wide range of services, improve the organization of technical service and expand direct links with the manufacturers of equipment in order to respond quickly and make the necessary design and technological decisions.

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Nonlinear Viscoelastic Finite Element Analysis of Adhesive Joints

Tire Science and Technology ◽

10.2346/1.2148803 ◽

1988 ◽

Vol 16 (3) ◽

pp. 146-170 ◽

Cited By ~ 4

Author(s):

S. Roy ◽

J. N. Reddy

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Viscoelastic Behavior ◽

Bonded Joints ◽

Adhesively Bonded ◽

Element Analysis ◽

Adhesively Bonded Joints ◽

Nonlinear Viscoelastic ◽

Structural Failures ◽

Updated Lagrangian

Abstract A good understanding of the process of adhesion from the mechanics viewpoint and the predictive capability for structural failures associated with adhesively bonded joints require a realistic modeling (both constitutive and kinematic) of the constituent materials. The present investigation deals with the development of an Updated Lagrangian formulation and the associated finite element analysis of adhesively bonded joints. The formulation accounts for the geometric nonlinearity of the adherends and the nonlinear viscoelastic behavior of the adhesive. Sample numerical problems are presented to show the stress and strain distributions in bonded joints.

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Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

Biogeosciences ◽

10.5194/bg-12-5871-2015 ◽

2015 ◽

Vol 12 (19) ◽

pp. 5871-5883 ◽

Cited By ~ 7

Author(s):

L. A. Melbourne ◽

J. Griffin ◽

D. N. Schmidt ◽

E. J. Rayfield

Keyword(s):

Climate Change ◽

Finite Element ◽

Structural Integrity ◽

Geometric Model ◽

Algal Growth ◽

Coralline Algae ◽

Rocky Shores ◽

Element Analysis ◽

Scan Data ◽

The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

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Site‐specific nitrogen balances based on spatially variable soil and plant properties

Precision Agriculture ◽

10.1007/s11119-021-09789-9 ◽

2021 ◽

Author(s):

Martin Mittermayer ◽

August Gilg ◽

Franz-Xaver Maidl ◽

Ludwig Nätscher ◽

Kurt-Jürgen Hülsbergen

Keyword(s):

Soil Properties ◽

N Uptake ◽

Nitrate Content ◽

Site Specific ◽

Nitrate Losses ◽

Wide Range ◽

Reduction Strategies ◽

Combine Harvester ◽

Digital Methods ◽

Collection Methods

AbstractIn this study, site-specific N balances were calculated for a 13.1 ha heterogeneous field. Yields and N uptake as input data for N balances were determined with data from a combine harvester, reflectance measurements from satellites and tractor-mounted sensors. The correlations between the measured grain yields and yields determined by digital methods were moderate. The calculated values for the N surpluses had a wide range within the field. Nitrogen surpluses were calculated from − 76.4 to 91.3 kg ha−1, with a mean of 24.0 kg ha−1. The use of different data sources and data collection methods had an impact on the results of N balancing. The results show the need for further optimization and improvement in the accuracy of digital methods. The factors influencing N uptake and N surplus were determined by analysing soil properties of georeferenced soil samples. Soil properties showed considerable spatial variation within the field. Soil organic carbon correlated very strongly with total nitrogen content (r = 0.97), moderately with N uptake (sensor, r = 0.60) and negatively with N surplus (satellite, r = − 0.46; sensor, r = − 0.56; harvester, r = − 0.60). Nitrate content was analysed in soil cores (0 to 9 m) taken in different yield zones, and compared with the calculated N surplus; there was a strong correlation between the measured nitrate content and calculated N surplus (r = 0.82). Site-specific N balancing can contribute to a more precise identification of the risk of nitrate losses and the development of targeted nitrate reduction strategies.

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Design of 3D Additively Manufactured Hybrid Structures for Cranioplasty

Materials ◽

10.3390/ma14010181 ◽

2021 ◽

Vol 14 (1) ◽

pp. 181

Author(s):

Roberto De Santis ◽

Teresa Russo ◽

Julietta V. Rau ◽

Ida Papallo ◽

Massimo Martorelli ◽

...

Keyword(s):

Physical Models ◽

Cranial Bone ◽

Head Model ◽

Rigid Sphere ◽

Element Analysis ◽

Aliphatic Polyesters ◽

Hybrid Device ◽

Wide Range ◽

Hybrid Devices ◽

Technical Solutions

A wide range of materials has been considered to repair cranial defects. In the field of cranioplasty, poly(methyl methacrylate) (PMMA)-based bone cements and modifications through the inclusion of copper doped tricalcium phosphate (Cu-TCP) particles have been already investigated. On the other hand, aliphatic polyesters such as poly(ε-caprolactone) (PCL) and polylactic acid (PLA) have been frequently investigated to make scaffolds for cranial bone regeneration. Accordingly, the aim of the current research was to design and fabricate customized hybrid devices for the repair of large cranial defects integrating the reverse engineering approach with additive manufacturing, The hybrid device consisted of a 3D additive manufactured polyester porous structures infiltrated with PMMA/Cu-TCP (97.5/2.5 w/w) bone cement. Temperature profiles were first evaluated for 3D hybrid devices (PCL/PMMA, PLA/PMMA, PCL/PMMA/Cu-TCP and PLA/PMMA/Cu-TCP). Peak temperatures recorded for hybrid PCL/PMMA and PCL/PMMA/Cu-TCP were significantly lower than those found for the PLA-based ones. Virtual and physical models of customized devices for large cranial defect were developed to assess the feasibility of the proposed technical solutions. A theoretical analysis was preliminarily performed on the entire head model trying to simulate severe impact conditions for people with the customized hybrid device (PCL/PMMA/Cu-TCP) (i.e., a rigid sphere impacting the implant region of the head). Results from finite element analysis (FEA) provided information on the different components of the model.

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Improvement of the Detection Sensitivity of Edxrf Trace Element Analysis by Means of Efficient X-Ray Focusing Based on Strongly Curved Hopg Crystals

Advances in X-ray Analysis ◽

10.1154/s0376030800022515 ◽

1995 ◽

Vol 39 ◽

pp. 109-117

Author(s):

Burkhard Beckhoff ◽

Birgit Kanngießer

Keyword(s):

High Intensity ◽

Focal Plane ◽

Bragg Reflection ◽

Pyrolytic Graphite ◽

Trace Element Analysis ◽

Detection Sensitivity ◽

Element Analysis ◽

X Ray ◽

Wide Range ◽

Very High

X-ray focusing based on Bragg reflection at curved crystals allows collection of a large solid angle of incident radiation, monochromatization of this radiation, and condensation of the beam reflected at the crystal into a small spatial cross-section in a pre-selected focal plane. Thus, for the Bragg reflected radiation, one can achieve higher intensities than for the radiation passing directly to the same small area in the focal plane. In that case one can profit considerably from X-ray focusing in an EDXRF arrangement. The 00 2 reflection at Highly Oriented Pyrolytic Graphite (HOPG) crystals offers a very high intensity of the Bragg reflected beam for a wide range of photon energies. Furthermore, curvature radii smaller than 10 mm can be achieved for HOPG crystals ensuring efficient X-ray focusing in EDXRF applications. For the trace analysis of very small amounts of specimen material deposited on small areas of thin-filter backings, HOPG based X-ray focusing may be used to achieve a very high intensity of monochromatic excitation radiation.

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CFD Simulation of Fluid Flow Through Porous Media: Application to Decomposed Gases Flow Through Foam Pattern in Lost Foam Casting

Materials ◽

10.1115/imece2003-43500 ◽

2003 ◽

Cited By ~ 1

Author(s):

Sayavur I. Bakhtiyarov ◽

Ruel A. Overfelt

Keyword(s):

Cfd Simulation ◽

Reynolds Numbers ◽

Phase Flow ◽

Flow Through Porous Media ◽

Foam Material ◽

Element Analysis ◽

Wide Range ◽

Flow Through ◽

Foam Pattern ◽

Lost Foam

Numerical simulation of decomposed gases through foam pattern was conducted using finite element analysis. A new kinetic model is proposed for gaseos phase flow between molten metal and foam material. The computations were performed for a wide range of Reynolds numbers. The results of the simulations are compared with the experiemental data obtained in this study.

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NOVEL COUPLING CONSTRAINT TECHNIQUE FOR EXPLICIT FINITE ELEMENT ANALYSIS

International Journal of Computational Methods ◽

10.1142/s0219876204000150 ◽

2004 ◽

Vol 01 (02) ◽

pp. 309-328

Author(s):

R. J. HO ◽

S. A. MEGUID ◽

R. G. SAUVÉ

Keyword(s):

Finite Element ◽

Current Method ◽

Explicit Integration ◽

Rotation Tensor ◽

Element Analysis ◽

Explicit Finite Element ◽

Explicit Finite Element Analysis ◽

Wide Range ◽

Large Rotations ◽

Generalized Constraint

This paper presents a unified novel technique for enforcing nonlinear beam-to-shell, beam-to-solid, and shell-to-solid constraints in explicit finite element formulations. The limitations of classical multi-point constraint approaches are examined at length, particularly in the context of explicit solution schemes. Novel formulation of a generalized constraint method that ensures proper element coupling is then presented, and its computer implementation in explicit integration algorithms is discussed. Crucial in this regard is the accurate and efficient representation of finite rotations, accomplished using an incremental rotation tensor. The results of some illustrative test cases show the accuracy and robustness of the newly developed algorithm for a wide range of deformation, including that in which large rotations are encountered. When compared to existing works, the salient features of the current method are in evidence.

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Measurement and Calculation of Elastic Properties in Low Carbon Steel Sheet

Materials Science Forum ◽

10.4028/www.scientific.net/msf.495-497.1591 ◽

2005 ◽

Vol 495-497 ◽

pp. 1591-1596 ◽

Cited By ~ 3

Author(s):

Vladimir Luzin ◽

S. Banovic ◽

Thomas Gnäupel-Herold ◽

Henry Prask ◽

R.E. Ricker

Keyword(s):

Carbon Steel ◽

Elastic Property ◽

Elastic Properties ◽

Steel Sheet ◽

Low Carbon Steel ◽

Low Carbon ◽

Forming Process ◽

Element Analysis ◽

Wide Range ◽

Carbon Steel Sheet

Low carbon steel (usually in sheet form) has found a wide range of applications in industry due to its high formability. The inner and outer panels of a car body are good examples of such an implementation. While low carbon steel has been used in this application for many decades, a reliable predictive capability of the forming process and “springback” has still not been achieved. NIST has been involved in addressing this and other formability problems for several years. In this paper, texture produced by the in-plane straining and its relationship to springback is reported. Low carbon steel sheet was examined in the as-received condition and after balanced biaxial straining to 25%. This was performed using the Marciniak in-plane stretching test. Both experimental measurements and numerical calculations have been utilized to evaluate anisotropy and evolution of the elastic properties during forming. We employ several techniques for elastic property measurements (dynamic mechanical analysis, static four point bending, mechanical resonance frequency measurements), and several calculation schemes (orientation distribution function averaging, finite element analysis) which are based on texture measurements (neutron diffraction, electron back scattering diffraction). The following objectives are pursued: a) To test a range of different experimental techniques for elastic property measurements in sheet metals; b) To validate numerical calculation methods of the elastic properties by experiments; c) To evaluate elastic property changes (and texture development) during biaxial straining. On the basis of the investigation, recommendations are made for the evaluation of elastic properties in textured sheet metal.

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A Geometric Parametric Analysis of a Magnetorheological Engine Mount

Volume 4: 12th International Conference on Advanced Vehicle and Tire Technologies; 4th International Conference on Micro- and Nanosystems ◽

10.1115/detc2010-28941 ◽

2010 ◽

Author(s):

Walter Anderson ◽

Constantine Ciocanel ◽

Mohammad Elahinia

Keyword(s):

High Frequency ◽

New Technology ◽

Low Frequency ◽

Variable Stiffness ◽

Small Displacement ◽

Element Analysis ◽

Mr Fluid ◽

Wide Range ◽

Engine Mount ◽

Vehicle Technology

Engine vibration has caused a great deal of research for isolation to be performed. Traditionally, isolation was achieved through the use of pure elastomeric (rubber) mounts. However, with advances in vehicle technology, these types of mounts have become inadequate. The inadequacy stems from the vibration profile associated with the engine, i.e. high displacement at low frequency and small displacement at high frequency. Ideal isolation would be achieved through a stiff mount for low frequency and a soft mount for high frequency. This is contradictory to the performance of the elastomeric mounts. Hydraulic mounts were then developed to address this problem. A hydraulic mount has variable stiffness and damping due to the use of a decoupler and an inertia track. However, further advances in vehicle technology have rendered these mounts inadequate as well. Examples of these advances are hybridization (electric and hydraulic) and cylinder on demand (VCM, MDS & ACC). With these technologies, the vibration excitation has a significantly different profile, occurs over a wide range of frequencies, and calls for a new technology that can address this need. Magnetorheological (MR) fluid is a smart material that is able to change viscosity in the presence of a magnetic field. With the use of MR fluid, variable damping and stiffness can be achieved. An MR mount has been developed and tested. The performance of the mount depends on the geometry of the rubber part as well as the behavior of the MR fluid. The rubber top of the mount is the topic of this study due to its major impact on the isolation characteristics of the MR mount. To develop a design methodology to address the isolation needs of different hybrid vehicles, a geometric parametric finite element analysis has been completed and presented in this paper.

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Analysis of Thick-Walled Pipeline Elements Operating in Creep Conditions

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.712.63 ◽

2015 ◽

Vol 712 ◽

pp. 63-68

Author(s):

Przemysław Osocha ◽

Bohdan Węglowski

Keyword(s):

Finite Element ◽

Test Data ◽

Creep Test ◽

Power Plants ◽

Steam Pressure ◽

Creep Model ◽

Creep Process ◽

Fe Model ◽

Element Analysis ◽

Wide Range

In some coal-fired power plants, pipeline elements have worked for over 200 000 hours and increased number of failures is observed. The paper discuses thermal wear processes that take place in those elements and lead to rupture. Mathematical model based on creep test data, and describing creep processes for analyzed material, has been developed. Model has been verified for pipeline operating temperature, lower than tests temperature, basing on Larson-Miller relation. Prepared model has been used for thermal-strength calculations based on a finite element method. Processes taking place inside of element and leading to its failure has been described. Than, basing on prepared mathematical creep model and FE model introduced to Ansys program further researches are made. Analysis of dimensions and shape of pipe junction and its influence on operational element lifetime is presented. In the end multi variable dependence of temperature, steam pressure and element geometry is shown, allowing optimization of process parameters in function of required operational time or maximization of steam parameters. The article presents wide range of methods. The creep test data were recalculated for operational temperature using Larson-Miller parameter. The creep strain were modelled, used equations and their parameters are presented. Analysis of errors were conducted. Geometry of failing pipe junction was introduced to the Ansys program and the finite element analysis of creep process were conducted.

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