Evaluation of macro finite elements for use in global/local analysis of textile composites

2011 ◽  
Vol 46 (9) ◽  
pp. 1111-1125 ◽  
Author(s):  
Kevin S Maxwell ◽  
John D Whitcomb

Textile composites are ideal candidates for global/local finite element analysis because the global response of composites is so dependent on the complex microstructure of the weave. However, most global/local methods use homogenization to approximate the global material properties, which results in loss of information about material architecture. In this work, single field and multi-field macro-elements were used to account for material inhomogeneity within each element in the global region. The effectiveness of these macro-elements vs. using homogenized properties was evaluated for several configurations. It was found that using macro-elements in the global region of a model generally yields greater accuracy than using homogenized properties.

Author(s):  
Joonas Ponkala ◽  
Mohsin Rizwan ◽  
Panos S. Shiakolas

The current state of the art in coronary stent technology, tubular structures used to keep the lumen open, is mainly populated by metallic stents coated with certain drugs to increase biocompatibility, even though experimental biodegradable stents have appeared in the horizon. Biodegradable polymeric stent design necessitates accurate characterization of time dependent polymer material properties and mechanical behavior for analysis and optimization. This manuscript presents the process for evaluating material properties for biodegradable biocompatible polymeric composite poly(diol citrate) hydroxyapatite (POC-HA), approaches for identifying material models and three dimensional solid models for finite element analysis and fabrication of a stent. The developed material models were utilized in a nonlinear finite element analysis to evaluate the suitability of the POC-HA material for coronary stent application. In addition, the advantages of using femtosecond laser machining to fabricate the POC-HA stent are discussed showing a machined stent. The methodology presented with additional steps can be applied in the development of a biocompatible and biodegradable polymeric stents.


2006 ◽  
Vol 532-533 ◽  
pp. 993-996
Author(s):  
Anthony Yee Kai Yam ◽  
Kai Leung Yung ◽  
Chi Wo Lam

Toys that are free from drop failures normally take a long time to develop. It is often time and cost consuming after the production tooling is built to detect drop test failure. This paper introduces a new drop testing analysis method for Toys. The method uses a simple approach with a local analysis that based on the linear and non linear finite element analysis. Modeling and transient drop analysis of a pre-school toy is used as a case study to demonstrate the method. The impact analysis of the product hitting the solid concrete floor after a free fall is presented. The analysis focuses on the deformation of the housing for a product with electronic circuit and mechanical mechanism inside. Experimental data has been obtained for drop simulation of the housing and its correlation with the plastic material properties. The stress and strain of the housing during drop impact tests are noted. The effects of the material properties to the housing deflection under drop/impact shock have been investigated. Numerical results are compared with experimental results to validate the method.


2021 ◽  
Vol 21 (5) ◽  
pp. 2987-2991
Author(s):  
Geumtaek Kim ◽  
Daeil Kwon

Along with the reduction in semiconductor chip size and enhanced performance of electronic devices, high input/output density is a desired factor in the electronics industry. To satisfy the high input/output density, fan-out wafer-level packaging has attracted significant attention. While fan-out wafer-level packaging has several advantages, such as lower thickness and better thermal resistance, warpage is one of the major challenges of the fan-out wafer-level packaging process to be minimized. There have been many studies investigating the effects of material properties and package design on warpage using finite element analysis. Current warpage simulations using finite element analysis have been routinely conducted with deterministic input parameters, although the parameter values are uncertain from the manufacturing point of view. This assumption may lead to a gap between the simulation and the field results. This paper presents an uncertainty analysis of wafer warpage in fan-out wafer-level packaging by using finite element analysis. Coefficient of thermal expansion of silicon is considered as a parameter with uncertainty. The warpage and the von Mises stress are calculated and compared with and without uncertainty.


1999 ◽  
Vol 36 (04) ◽  
pp. 203-210
Author(s):  
Steven P. McGee ◽  
Armin Troesch ◽  
Nickolas Vlahopoulos

In 1994 the International Maritime Organization adopted the Code of Safety for High-Speed Craft (HSC Code). After two years of use, several shortfalls were found, one being the damage length predictor, which is based on traditional steel, mono-hulled vessels. Other damage predictors were developed based on historical data, but they do not account for variables such as aluminum or fiberglass construction, transverse members, indenter geometry variation, or for the case where the vessel comes to rest on the grounding object. This paper proposes a damage prediction model based on material properties, structural layout, grounding object geometry, and vessel speed. The model incorporates four grounding mechanisms: plate cutting, plate tearing, crushing of plate behind transverse members, and transverse member failure. The method is used to determine the resistance energy, compared to the kinetic energy, of the vessel, to determine an effective damage length. Finite-element analysis was used to model the failure of both aluminum and steel transverse members with significant differences in the results. It was found that the transverse members provided the majority of the resistance energy in one grounding mechanism and negligible resistance energy in another.


2019 ◽  
Vol 257 ◽  
pp. 02004
Author(s):  
Zhenhai Huang ◽  
Tingchun Shi ◽  
Xiuyan Yue

In view of the forming accuracy of the 3D printer, the paper, from the structure of the printer itself, discussed the influence on the precision of the printer via improving the structure of 3D printer. A typical 3D printer, such as a common type of FDM, was selected, and SOLIDWORKS software was used for solid modeling, after establishing the model, the finite element analysis was carried out on the whole structure model to obtain the deformation characteristics and the main vibration model of the printer. On the basis of finite element analysis, the influence of the level shaft bearing diameter, material properties and symmetry of the parts on the overall mechanical properties of the printer was discussed respectively. On this basis, the overall structure of the machine has been optimized and achieved remarkable results.


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