scholarly journals Improved Predictive Modeling Techniques for Non-Linear Solder Material Behavior

2021 ◽  
Author(s):  
◽  
Arman Ahari
Keyword(s):  
Predictive Modeling ◽  
Material Behavior ◽  
Solder Material ◽  
Modeling Techniques ◽  
Non Linear

Predictive modeling techniques of software quality from software measures

1992 ◽  
Vol 18 (11) ◽  
pp. 979-987 ◽  
Author(s):  
T.M. Khoshgoftaar ◽  
J.C. Munson ◽  
B.B. Bhattacharya ◽  
G.D. Richardson
Keyword(s):  
Predictive Modeling ◽  
Software Quality ◽  
Modeling Techniques ◽  
Software Measures

An Analysis of the Use of Predictive Modeling with Business Intelligence Systems for Exploration of Precious Metals Using Biogeochemical Data

2013 ◽  
Vol 4 (2) ◽  
pp. 39-53 ◽  
Author(s):  
Thomas A. Woolman ◽  
John C. Yi
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Anomaly Detection ◽  
Predictive Modeling ◽  
Business Intelligence ◽  
Precious Metals ◽  
Geological Exploration ◽  
Feed Forward ◽  
Business Intelligence Systems ◽  
Modeling Techniques

This study addresses the use of predictive modeling techniques; primarily feed-forward artificial neural networks as a tool for forecasting geological exploration targets for gold prospecting. It also provides evidence of effectiveness of using Business Intelligence systems to model pathfinder variables, anomaly detection, and forecasting to locate potential exploration sites for precious metals. The results indicate that the use of advanced Business Intelligence systems can be of extremely high value to the extractive minerals exploration industry.

Aggregation for Predictive Modeling with Relational Data

2011 ◽  
pp. 33-38
Author(s):  
Claudia Perlich ◽  
Foster Provost
Keyword(s):  
Data Mining ◽  
Predictive Modeling ◽  
Relational Databases ◽  
Feature Vector ◽  
Relational Data ◽  
Government Organizations ◽  
Modeling Techniques ◽  
Aggregation Of Information ◽  
New Challenges

Most data mining and modeling techniques have been developed for data represented as a single table, where every row is a feature vector that captures the characteristics of an observation. However, data in most domains are not of this form and consist of multiple tables with several types of entities. Such relational data are ubiquitous; both because of the large number of multi-table relational databases kept by businesses and government organizations, and because of the natural, linked nature of people, organizations, computers, and etc. Relational data pose new challenges for modeling and data mining, including the exploration of related entities and the aggregation of information from multi-sets (“bags”) of related entities.

Soil-Structure Interaction of Heated Pipeline Buried in Soft Clay

2002 ◽  
Author(s):  
Alvaro Maia da Costa ◽  
Carlos de Oliveira Cardoso ◽  
Claudio dos Santos Amaral ◽  
Alejandro Andueza
Keyword(s):  
Challenging Behavior ◽  
Soft Clay ◽  
Back Analysis ◽  
Interaction Model ◽  
Material Behavior ◽  
Soil Reaction ◽  
Inelastic Behavior ◽  
Guanabara Bay ◽  
Structure Interaction ◽  
Non Linear

Heated pipelines buried in soft clay can develop a very challenging behavior. The thermal expansion of the pipelines normally induces buckles, which will be supported by the passive soil reaction. The buckles of the pipelines in soft clay can generate a non-linear inelastic behavior that is an unstable situation named “snap through”. In such situation the pipeline can jump from a configuration of a few centimeters displacement to another of meters displacement. Once the snap through situation has developed, there is the possibility of a local pipeline buckling, causing the pipeline rupture and as a consequence an oil spill. This paper presents the results obtained during the analysis of the rupture of a buried heated pipeline in the Guanabara Bay of Rio de Janeiro, Brazil. A very sophisticated procedure including a simulation of the thermal mechanical interactions between the soil and the pipeline structure was developed for back analysis of the thermal inelastic pipeline buckling. Computer modeling was carried out using the finite element method considering of the non-linear material behavior of the soil and pipeline, and nonlinear geometrical behavior of the pipeline. A cyclic thermal-mechanical soil-pipeline structure interaction model was the challenging aspect of the simulation, that explains the trigger mechanism of the snap through behavior of heated pipelines, which was responsible for the rupture of the pipeline in Guanabara Bay.

FEA Based Reliability Predictions for PBGA Packages Subjected to Isothermal Aging Prior to Thermal Cycling

2015 ◽  
Author(s):  
Munshi Basit ◽  
Mohammad Motalab ◽  
Jeffrey C. Suhling ◽  
John L. Evans ◽  
Pradeep Lall
Keyword(s):  
Finite Element ◽  
Solder Joint ◽  
Thermal Cycling ◽  
Isothermal Aging ◽  
Material Behavior ◽  
Lead Free ◽  
Stress Strain ◽  
Solder Material ◽  
Free Solder ◽  
Temperature Aging

The microstructure, mechanical response, and failure behavior of lead free solder joints in electronic assemblies are constantly evolving when exposed to isothermal aging and/or thermal cycling environments. In our prior work on aging effects, we have demonstrated that the observed material behavior degradations of Sn-Ag-Cu (SAC) lead free solders during room temperature aging (25 C) and elevated temperature aging (50, 75, 100, 125, and 150 C) were unexpectedly large. The measured stress-strain data demonstrated large reductions in stiffness, yield stress, ultimate strength, and strain to failure (up to 50%) during the first 6 months after reflow solidification. In this study, we have used both accelerated life testing and finite element modeling to explore how prior isothermal aging affects the overall reliability of PBGA packages subjected to thermal cycling. In the experimental work, an extensive test matrix of thermal cycling reliability testing has been performed using a test vehicle incorporating several sizes (5, 10, 15, 19 mm) of BGA daisy chain components with 0.4 and 0.8 mm solder joint pitches (SAC305). PCB test boards with 3 different surface finishes (ImAg, ENIG and ENEPIG) were utilized. In this paper, we concentrate on the reporting the results for a PBGA component with 15 mm body size. Before thermal cycling began, the assembled test boards were divided up into test groups that were subjected to several sets of aging conditions (preconditioning) including 0, 6, and 12 months aging at T = 125 °C. After aging, the assemblies were subjected to thermal cycling (−40 to +125 °C) until failure occurred. The Weibull data failure plots have demonstrated that the thermal cycling reliabilities of pre-aged assemblies were significantly less than those of non-aged assemblies. A three-dimensional finite element model of the tested 15 mm PBGA packages was also developed. The cross-sectional details of the solder ball and the internal structure of the BGA were examined by scanning electron microscopy (SEM) to capture the real geometry of the package. Simulations of thermal cycling from −40 to 125 C were performed. To include the effects of aging in the calculations, we have used a revised set of Anand viscoplastic stress-strain relations for the SAC305 Pb-free solder material that includes material parameters that evolve with the thermal history of the solder material. The accumulated plastic work (energy density dissipation) was used is the failure variable; and the Darveaux approach to predict crack initiation and crack growth was applied with aging dependent parameters to estimate the fatigue lives of the studied packages. We have obtained good correlation between our new reliability modeling procedure that includes aging and the measured solder joint reliability data. As expected from our prior studies on degradation of SAC material properties with aging, the reliability reductions were more severe for higher aging temperature and longer aging times.

Finite Element Analysis of a Locked Bolt With an Initial Crack

2009 ◽  
Author(s):  
Jean Paul Kabche ◽  
Mauri´cio Rangel Pacheco ◽  
Ivan Thesi ◽  
Luiz Carlos Largura
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Operating Conditions ◽  
Material Behavior ◽  
Isotropic Hardening ◽  
Stress Concentrations ◽  
Engineering Structures ◽  
Element Analysis ◽  
Micro Cracks ◽  
Non Linear

Bolted connections are largely employed in various types of engineering structures to transfer loads from one member to another. In particular, the off-shore industry has made extensive use of these connections, predominantly at the sub-sea level. In spite of their advantages, bolted joints are critical regions and may become sources of structural weakness due to large stress concentrations. Under severe operating conditions, micro-cracks can develop in the bolt, creating regions of elevated stress which may significantly reduce the integrity of the connection and ultimately lead to failure. This paper presents the three-dimensional finite element analysis of a steel locked bolt assembly aimed to assess the effect of micro-cracks on the structural integrity of the assembly using the commercial finite element package ANSYS. Non-linear contact between the bolt and nut threads is considered, where frictional sliding between components is allowed. A bi-linear isotropic hardening model is used to account for non-linear material behavior. The assembly is loaded by applying a pre-load of fifty percent of the yield stress of the material, according to the API-6A Norm. Two geometric models are investigated: a healthy locked bolt assembly with no initial cracks; and a damaged model, where a circular crack is introduced at the root of the bolt threads. The effect of the crack size is studied by modeling the crack with three different radius sizes. The J-Integral fracture mechanics methodology was used to study the stress concentrations in the damaged model.

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