scholarly journals A Geometry-Based Welding Distortion Prediction Tool

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4789
Author(s):  
Ignacio Granell ◽  
Abel Ramos ◽  
Alberto Carnicero
Keyword(s):  
Material Properties ◽  
Nonlinear Material ◽  
Welding Distortion ◽  
Coupled Analysis ◽  
Simulation Tool ◽  
Loosely Coupled ◽  
Python Scripting ◽  
Automated Simulation ◽  
Definition Of ◽  
Automatic Simulation

The prediction of welding distortion requires expertise in computer simulation programs, a clear definition of the nonlinear material properties, and mesh settings together with the nonlinear solution settings of a coupled thermal–structural analysis. The purpose of this paper is to present the validation of an automatic simulation tool implemented in Ansys using Python scripting. This tool allows users to automate the preparation of the simulation model with a reduced number of inputs. The goal was, based on some assumptions, to provide an automated simulation setup that enables users to predict accurate distortion during the welding manufacturing process. Any geometry prepared in a CAD software can be used as the input, which gave us much geometrical flexibility in the shapes and sizes to be modeled. A thermomechanical loosely coupled analysis approach together with element birth and death technology was used to predict the distortions. The automation of the setup enables both simulation and manufacturing engineers to perform welding-induced distortion prediction. The results showed that the method proposed predicts distortion with 80–98% accuracy.

scholarly journals Connecting Data Publication to the Research Workflow: A Preliminary Analysis

2017 ◽  
Vol 12 (1) ◽  
pp. 88-105 ◽  
Author(s):  
Sünje Dallmeier-Tiessen ◽  
Varsha Khodiyar ◽  
Fiona Murphy ◽  
Amy Nurnberger ◽  
Lisa Raymond ◽  
...  
Keyword(s):  
Working Group ◽  
Research Data ◽  
Data Publishing ◽  
Data Repository ◽  
Research Activity ◽  
Data Repositories ◽  
Data Publication ◽  
Loosely Coupled ◽  
Definition Of ◽  
Data Documentation

The data curation community has long encouraged researchers to document collected research data during active stages of the research workflow, to provide robust metadata earlier, and support research data publication and preservation. Data documentation with robust metadata is one of a number of steps in effective data publication. Data publication is the process of making digital research objects ‘FAIR’, i.e. findable, accessible, interoperable, and reusable; attributes increasingly expected by research communities, funders and society. Research data publishing workflows are the means to that end. Currently, however, much published research data remains inconsistently and inadequately documented by researchers. Documentation of data closer in time to data collection would help mitigate the high cost that repositories associate with the ingest process. More effective data publication and sharing should in principle result from early interactions between researchers and their selected data repository. This paper describes a short study undertaken by members of the Research Data Alliance (RDA) and World Data System (WDS) working group on Publishing Data Workflows. We present a collection of recent examples of data publication workflows that connect data repositories and publishing platforms with research activity ‘upstream’ of the ingest process. We re-articulate previous recommendations of the working group, to account for the varied upstream service components and platforms that support the flow of contextual and provenance information downstream. These workflows should be open and loosely coupled to support interoperability, including with preservation and publication environments. Our recommendations aim to stimulate further work on researchers’ views of data publishing and the extent to which available services and infrastructure facilitate the publication of FAIR data. We also aim to stimulate further dialogue about, and definition of, the roles and responsibilities of research data services and platform providers for the ‘FAIRness’ of research data publication workflows themselves.

Design of an Isotropic Metamaterial With Constant Stiffness and Zero Poisson's Ratio Over Large Deformations

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
A. Delissen ◽  
G. Radaelli ◽  
L. A. Shaw ◽  
J. B. Hopkins ◽  
J. L. Herder
Keyword(s):  
Young’S Modulus ◽  
Material Properties ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Sufficient Conditions ◽  
Material Design ◽  
Poisson's Ratio ◽  
Nonlinear Material ◽  
Large Strains ◽  
Planar Lattice

A great deal of engineering effort is focused on changing mechanical material properties by creating microstructural architectures instead of modifying chemical composition. This results in meta-materials, which can exhibit properties not found in natural materials and can be tuned to the needs of the user. To change Poisson's ratio and Young's modulus, many current designs exploit mechanisms and hinges to obtain the desired behavior. However, this can lead to nonlinear material properties and anisotropy, especially for large strains. In this work, we propose a new material design that makes use of curved leaf springs in a planar lattice. First, analytical ideal springs are employed to establish sufficient conditions for linear elasticity, isotropy, and a zero Poisson's ratio. Additionally, Young's modulus is directly related to the spring stiffness. Second, a design method from the literature is employed to obtain a spring, closely matching the desired properties. Next, numerical simulations of larger lattices show that the expectations hold, and a feasible material design is presented with an in-plane Young's modulus error of only 2% and Poisson's ratio of 2.78×10−3. These properties are isotropic and linear up to compressive and tensile strains of 0.12. The manufacturability and validity of the numerical model is shown by a prototype.

Evaluation of the Temperature Effect on the Viscoelastic Responses of Flexible Risers

2019 ◽  
Author(s):  
Junpeng Liu ◽  
Jinsheng Ma ◽  
Murilo Augusto Vaz ◽  
Menglan Duan
Keyword(s):  
Material Properties ◽  
Global Analysis ◽  
Viscoelastic Behavior ◽  
Step Test ◽  
Nonlinear Material ◽  
Polymer Layer ◽  
Axial Stiffness ◽  
Loading Frequency ◽  
Flexible Risers ◽  
Improved Model

Abstract Mechanical behavior of flexible risers can be challenging due largely to its complex design generating strong nonlinear problems. Nonlinear material properties, as one of them, from polymer layers dominate the overall viscoelastic responses of flexible risers which may play an inevitable role on the global analysis in deepwater application. An alternative to predict the viscoelastic behavior comprising of the time domain and the frequency domain has been proposed recently by the authors (Liu and Vaz, 2016). Given the fact that polymeric material properties are temperature-dependent and that the temperature profiles in flexile risers vary continuously in both axial and radial direction, the temperature of the internal hydrocarbons must affect the viscoelastic responses. However, such phenomenon dose not draw much attention in previous studies. This paper presents an improved model for overcoming some drawbacks in the proposed model involving assumption of steady temperature distribution in polymer layer and no gap appearance between the adjacent layers. The computing method of model is developed by using a step by step test approach. Consequently, some important parameters like equivalent axial stiffness, contact pressure or gap between the near layers, and force-deformation relationship can be observed. Parametric studies are conducted on the axisymmetric viscoelastic behavior of flexible risers to study the role of input temperature and loading frequency. Results show that equivalent axial stiffness given by the improved model is smaller than before. It can also be found that the gap between metal layer and polymer layer appear easily and increases as time goes on.

scholarly journals Setting the Common Ground: A Generic Framework for Material Flow Analysis of Complex Systems

Recycling ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 23 ◽  
Author(s):  
Julia Tanzer ◽  
Helmut Rechberger
Keyword(s):  
Material Flow ◽  
Common Ground ◽  
Flow Analysis ◽  
Material Flow Analysis ◽  
Coupled Analysis ◽  
Private Institutions ◽  
Common Basis ◽  
Generic Framework ◽  
Multiple Materials ◽  
Definition Of

Circular economy is currently characterized by various definitions, measurement approaches, and critical analyses thereof coexisting alongside each other. Whether the concept eventually prevails or collapses will depend to some extent on our success in harmonizing assessment methods among public, scientific, and private institutions, as well as across different materials and scales. Therefore, in this article, we present a generic material flow analysis framework that might serve as a common basis for circularity assessment, and test it by means of three case studies. It proved impossible to eliminate all subjective assumptions when transforming a real complex system into the generic framework, especially regarding the definition of by-products. However, by introducing subsystems it is at least possible to make such assumptions transparent. Therefore, adequate comparability across regions, materials, and scales is provided. Moreover, the generic system allows for coupled analysis of multiple materials simultaneously so that interactions between them can be studied, as well and a deeper insight into overall sustainability of the system can be gained.

Fracture Prediction for the Proximal Femur Using Finite Element Models: Part I—Linear Analysis

1991 ◽  
Vol 113 (4) ◽  
pp. 353-360 ◽  
Author(s):  
J. C. Lotz ◽  
E. J. Cheal ◽  
W. C. Hayes
Keyword(s):  
Finite Element ◽  
Fracture Risk ◽  
Strain Gage ◽  
Proximal Femur ◽  
Material Properties ◽  
The United States ◽  
Nonlinear Material ◽  
Finite Element Models ◽  
Model Predictions

Over 90 percent of the more than 250,000 hip fractures that occur annually in the United States are the result of falls from standing height. Despite this, the stresses associated with femoral fracture from a fall have not been investigated previously. Our objectives were to use three-dimensional finite element models of the proximal femur (with geometries and material properties based directly on quantitative computed tomography) to compare predicted stress distributions for one-legged stance and for a fall to the lateral greater trochanter. We also wished to test the correspondence between model predictions and in vitro strain gage data and failure loads for cadaveric femora subjected to these loading conditions. An additional goal was to use the model predictions to compare the sensitivity of several imaging sites in the proximal femur which are used for the in vivo prediction of hip fracture risk. In this first of two parts, linear finite element models of two unpaired human cadaveric femora were generated. In Part II, the models were extended to include nonlinear material properties for the cortical and trabecular bone. While there was poor correspondence between strain gage data and model predictions, there was excellent agreement between the in vitro failure data and the linear model, especially using a von Mises effective strain failure criterion. Both the onset of structural yielding (within 22 and 4 percent) and the load at fracture (within 8 and 5 percent) were predicted accurately for the two femora tested. For the simulation of one-legged stance, the peak stresses occurred in the primary compressive trabeculae of the subcapital region. However, for a simulated fall, the peak stresses were in the intertrochanteric region. The Ward’s triangle (basicervical) site commonly used for the clinical assessment of osteoporosis was not heavily loaded in either situation. These findings suggest that the intertrochanteric region may be the most sensitive site for the assessment of fracture risk due to a fall and the subcapital region for fracture risk due to repetitive activities such as walking.

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