Search Results for analytical modeling

Mathematical models have been used for over five decades in industrial heat-treating operations. Most of these modeling efforts have emanated from academia or research institutes, with the primary approach of mathematically capturing heat-treating processes and validating quality predictions. In this article, a contrarian but more realistic scenario is considered, where two industrial problem descriptions become the starting point. The technical complexity of the industry problem has been elaborated for a deeper understanding of the issue along with elaboration of the approach and potential methods for determining a solution. Then, quantitative analyses of practical industrial problems are demonstrated. Finally, the potential shift in these approaches with the advent of Industry 4.0 is outlined.

This article reviews the classical models for the pseudo-steady-state temperature distribution of the thermal field around moving point and line sources. These include thick- and thin-plate models and the medium-thick-plate model. The analytical solutions to the differential heat flow equation under conditions applicable to fusion welding are provided. The article also provides an overview of the factors affecting heat flow in a real welding situation using the analytical modeling approach because this makes it possible to derive relatively simple equations that provide the required background for an understanding of the temperature-time pattern.

There is a need for models that predict the percentage and size of porosity formed during solidification in order to effectively predict mechanical properties. This article provides an overview of equations that govern pore formation. It reviews the four classes of models, highlighting both the benefits and drawbacks of each class. These classes include criteria functions, analytical models, continuum models, and kinetic models. The article also tabulates the criteria functions for porosity prediction.

Friction stir welding (FSW) involves plastic deformation at high strain rates and elevated temperatures with resultant microstructural changes leading to joining. This article provides a link between deformation and FSW process parameters and summarizes the results of experimental temperature measurements during FSW of various metals. It considers the physical explanation of the heat input during FSW and the possible methods of their estimation. The article presents the experimental results of two analytical models, supplemented by experimental/numerical flow models on material flow during FSW. The types of defects, processing parameters affecting the generation of these defects, and results of theoretical models and simulations to understand the formation and control of defects during FSW are discussed. The article concludes with information on the microstructure and its distribution produced during FSW.

This article discusses the mechanics of chip formation and reviews the analytical modeling of the chip formation process by high-speed machining within the framework of continuum mechanics. It examines the relationship between the various high-speed machining parameters. The article describes the cutting tool systems for aluminum alloys, steel, superalloys, and titanium alloys and provides an overview of the alternative cutting tool geometries for increasing tool life. It highlights the factors considered by companies planning to employ high-speed machining systems and concludes with information on the applications of high-speed machining.

This article provides a discussion on the analytical modeling and simulation of residual stress states developed in steel parts and the reasons for these varied final stress states. It illustrates how the metallurgical phase transformation of steel alloys can be applied in the simulation of induction hardening processes and the role of these phase transformations in affecting stress and distortion. Emphasis is placed on induction surface hardening, which is the main application of induction heating in steel heat treatment. The article concludes with examples of induction surface-hardened shafts and through-hardened shafts made of plain carbon steel, alloy steel, and limited hardenability steel.

This article discusses the methods of analyzing the directional dependence of the mechanical properties of composites, especially those perpendicular to the major plane of the laminate. It provides a description of the common indirect load cases and direct out-of-plane load cases. The article concludes with a discussion on composite materials that are reinforced in the z-direction (also known as three-dimensional, or 3-D composites).

This article addresses the issue of the implementation of composite damage tolerance requirements as it relates to military aircraft. It presents a brief introduction on the durability impact threat, damage tolerance impact threat, and other damage tolerance damage threats. The article summarizes damage tolerance criteria and durability criteria for military aircraft. It discusses the damage tolerance design philosophy for metallic structures and composite structures of the aircraft. The article describes the implementation of a damage tolerance analysis methodology in terms of the mechanics based model, the regression algorithm, and the semi-empirical analysis.

This article examines how cellular automaton (CA) can be applied to the simulation of static and dynamic recrystallization. It describes the steps involved in the CA simulation of recrystallization. These include defining the CA framework, generating the initial microstructure, distributing nuclei of recrystallized grains, growing the recrystallized grains, and updating the dislocation density. The article concludes with information on the developments in CA simulations.

This article begins with information on the fundamentals of chip formation process and general considerations for the modeling and simulation of machining processes. It focuses on smaller-scale models that seek to characterize the workpiece/tool/chip interface and behaviors closely associated with that. The article describes the advantages and disadvantages of various finite-element modeling approaches, namely, transient models, continuous cutting model, steady-state model, hybrid model, two-dimensional models, and three-dimensional models. It discusses flow stress measurements using constitutive and inverse testing methods and reviews tool design for chip removal. The article explains the effect of tool geometry on burr formation and the effect of coatings on tool temperatures. It concludes with information on tool wear, which is an unavoidable effect of metal cutting.

Flanging is a process used to form a projecting rim or edge on a part. This article explores how to determine aluminum flanging limits in terms of fracture, wrinkling, and springback, and their influencing material and process parameters with examples.

In order to model macrosegregation, one must consider convection and the partitioning of segregating elements at the dendritic length scale. This article describes microsegregation with diffusion in the solid. It presents a continuum model of macrosegregation and illustrates the simulation of macrosegregation and microsegregation.

This article discusses several alternative mechanical test approaches that can be applied to additive manufacturing (AM) materials, both for smaller-scale assessments and for specimens that have been extracted from an AM component. This includes small punch testing, shear punch testing, and small ring testing.