This paper reviews recent progress in the development of silicon-based vapor chambers for heat spreading in electronic packages. Effective hotspot mitigation is an increasingly challenging issue in electronics thermal management, and the use of silicon vapor chambers creates opportunities for thermal-expansion matched, high performance heat spreaders that can be directly integrated with the semiconductor die. While silicon microheat pipes have been extensively studied as one-dimensional heat transport mechanisms for heat routing in semiconductor substrates, silicon vapor chambers require special consideration and different manufacturing approaches due to the different heat transport configurations involved. The following review therefore provides an overview on the evolution of silicon vapor chambers in terms of fabrication strategies and performance characterization. Particular focus is given to opportunities and challenges associated with using silicon as the vapor chamber envelope material rather than more traditional metal-based vapor chambers, such as the ability to optimize the wick geometry with greater fidelity and issues with manufacturing scalability.

Similitude theory allows engineers, through a set of tools known as similitude methods, to establish the necessary conditions to design a scaled (up or down) model of a full-scale prototype structure. In recent years, to overcome the obstacles associated with full-scale testing, such as cost and setup, research on similitude methods has grown and their application has expanded into many branches of engineering. The aim of this paper is to provide as comprehensive a review as possible about similitude methods applied to structural engineering and their limitations due to size effects, rate sensitivity phenomena, etc. After a brief historical introduction and a more in-depth analysis of the main methods, the paper focuses on similitude applications classified, first, by test article, then by engineering fields.

Topologically interlocked material (TIM) systems are load-carrying assemblies of unit elements interacting by contact and friction. TIM assemblies have emerged as a class of architectured materials with mechanical properties not ordinarily found in monolithic solids. These properties include, but are not limited to, high damage tolerance, damage confinement, adaptability, and multifunctionality. The review paper provides an overview of recent research findings on TIM manufacturing and TIM mechanics. We review several manufacturing approaches. Assembly manufacturing processes employ the concept of scaffold as a unifying theme. Scaffolds are understood as auxiliary support structures employed in the manufacturing of TIM systems. It is demonstrated that the scaffold can take multiple forms. Alternatively, processes of segmentation are discussed and demonstrated. The review on mechanical property characteristics links the manufacturing approaches to several relevant material configurations and details recent findings on quasi-static and impact loading, and on multifunctional response.

In Mechanics, material properties are most often regarded as being given, and based on this, many technical solutions are usually conceived and constructed. However, nowadays manufacturing processes have advanced to the point that metamaterials having selected properties can be designed and fabricated. Three-dimensional printing, electrospinning, self-assembly, and many other advanced manufacturing techniques are raising a number of scientific questions which must be addressed if the potential of these new technologies is to be fully realized. In this work, we report on the status of modeling and analysis of metamaterials exhibiting a rich and varied macroscopic response conferred by complex microstructures and particularly focus on strongly interacting inextensible or nearly inextensible fibers. The principal aim is to furnish a framework in which the mechanics of 3D rapid prototyping of microstructured lattices and fabrics can be clearly understood and exploited. Moreover, several-related open questions will be identified and discussed, and some methodological considerations of general interest are provided.

The interplay between the mechanical properties of cells and the forces that they produce internally or that are externally applied to them play an important role in maintaining the normal function of cells. These forces also have a significant effect on the progression of mechanically related diseases. To study the mechanics of cells, a wide variety of tools have been adapted from the physical sciences. These tools have helped to elucidate the mechanical properties of cells, the nature of cellular forces, and mechanoresponses that cells have to external forces, i.e., mechanotransduction. Information gained from these studies has been utilized in computational models that address cell mechanics as a collection of biomechanical and biochemical processes. These models have been advantageous in explaining experimental observations by providing a framework of underlying cellular mechanisms. They have also enabled predictive, in silico studies, which would otherwise be difficult or impossible to perform with current experimental approaches. In this review, we discuss these novel, experimental approaches and accompanying computational models. We also outline future directions to advance the field of cell mechanics. In particular, we devote our attention to the use of microposts for experiments with cells and a bio-chemical-mechanical model for capturing their unique mechanobiological properties.

This article is dedicated to the review of publications on drop impact analysis performed on consumer electronic devices such as cellular phones and two-way radios in the past decade. Prior to the highlights of this review, the scope and motivation behind this work will be briefly explained. A comprehensive survey on published literatures devoted to the methodologies established to analyze the reliability of electronic products exposed to the event of drop impact is presented. The scope of the review is extended beyond product level analysis to also include drop impact study at board level. This type of review is novel and has not been published in the past. The focus will be on the different analytical and numerical modeling approaches and the current status of finite element method in predicting the drop impact performance of electronic devices. Of equal interest is the methodology adopted in past work to establish a correlation between numerical and experimental results. This article serves as a reference to all intended future work which could be an extension from the current known art of drop impact analysis on electronic devices. The time frame of this review is up to year 2010.

We discuss the role and the attributes of, as well as the state-of-the-art and some major findings in, the area of predictive analytical (“mathematical”) thermal stress modeling in electronic, opto-electronic, and photonic engineering. The emphasis is on packaging assemblies and structures and on simple meaningful practical models that can be (and actually have been) used in the mechanical (“physical”) design and reliability evaluations of electronic, opto-electronic, and photonic assemblies, structures, and systems. We indicate the role, objectives, attributes, merits, and shortcomings of analytical modeling and discuss its interaction with finite-element analysis (FEA) simulations and experimental techniques. Significant attention is devoted to the physics of the addressed problems and the rationale behind the described models. The addressed topics include (1) the pioneering Timoshenko’s analysis of bimetal thermostats and its extension for bimaterial assemblies of finite size and with consideration of the role of the bonding layer of finite compliance; this situation is typical for assemblies employed in electronics and photonics; (2) thermal stresses and strains in solder joints and interconnections; (3) attributes of the “global” and “local” thermal expansion (contraction) mismatch and the interaction of the induced stresses; (4) thermal stress in assemblies adhesively bonded at the ends and in assemblies (structural elements) with a low-modulus bonding layer at the ends (for lower interfacial stresses); (5) thin film systems; (6) thermal stress induced bow and bow-free assemblies subjected to the change in temperature; (7) predicted thermal stresses in, and the bow of, plastic packages of integrated circuit devices, with an emphasis on moisture-sensitive packages; (8) thermal stress in coated optical fibers and some other photonic structures; and (9) mechanical behavior of assemblies with thermally matched components (adherends). We formulate some general design recommendations for adhesively bonded or soldered assemblies subjected to thermal loading and indicate an incentive for a wider use of probabilistic methods in physical design for reliability of “high-technology” assemblies, including those subjected to thermal loading. Finally, we briefly address the role of thermal stress modeling in composite nanomaterials and nanostructures. It is concluded that analytical modeling should be used, whenever possible, along with computer-aided simulations (FEA) and accelerated life testing, in any significant engineering effort, when there is a need to analyze and design, in a fast, inexpensive, and insightful way, a viable, reliable, and cost-effective electronic, opto-electronic, or photonic assembly, package, or system.

A comprehensive review and assessment of the electromagnetic forming process is presented. Even though electromagnetic forming is a technology known for a few decades, renewed interest in it for industrial applications is currently taking place. Emphasis is mainly placed on the physical phenomena that govern the process as well as its main technological aspects, such as magnetic forming and joining, magnetic pulse welding, and dynamic magnetic compaction of powders. Moreover, some other important subjects concerning electromagnetic forming such as process equipment and workpiece formability are briefly presented in this paper. Applications of the process, mainly regarding manufacturing of advanced materials, are presented and discussed. This review article cites 149 references.

A fast growing volume of literature in various fields of composite materials and structures has inspired the authors to attempt to assemble all major books and review papers in a concise compendium presented here. This could give researchers, engineers, designers, and graduate students a rapid access to the vast volume of references on any specific topic in the field of composites and thereby satisfy their research requirements. The compendium includes encyclopedias, handbooks, design guides, textbooks, reference books, review papers and also a few collections of papers. The topics span theory, modeling and analysis of composite materials, processing and manufacturing, properties and characterization, theory and analysis of composite structures, joints and connections, designing with composites, and composites applications. The compendium includes over 400 references, which are arranged in alphabetical order within each topic under consideration. Additionally, the reader can find, in this compendium, the lists of major conferences, journals, and ASTM STP publications on composites. The major objective of this work is not critically reviewing or discussing specific research approaches and results. The authors have rather intended to provide extensive bibliographic information that may help the reader to get familiar with the primary literature and, if necessary, undertake further literature search on any particular problem of interest.

This article presents a review of constitutive theories, mechanics, and structural applications of shape memory alloys. Although these materials possess a number of unique features, this review is concerned with the shape memory effect and superelasticity, since they are most often discussed in the context of possible applications. The article begins with a discussion of these effects and a reference to a number of studies elucidating the properties of shape memory alloys. In the next section, a number of constitutive theories are listed and some recent theories are discussed in detail. The work related to numerous technological problems that arise in the process of manufacturing shape memory alloy structures is considered. Structural problems of shape memory structures, such as buckling, vibration, acoustic control, etc are discussed. The work related to development and design of shape memory sensors and actuators is also reviewed. Finally, some applications of shape memory alloy actuators, particularly those in the aerospace and medical fields, are considered. This review article contains 195 references.

A two-dimensional, curvilinear, isoparametric finite element is used to provide a discrete layer analysis of deformations and stresses in stiffened composite cylinders subjected to thermal-mechanical loading. Individual layers of the cylinder and the stiffener are modeled explicitly, providing an accurate and detailed representation of deformations and stresses including interlaminar stresses. Several skin and stiffener laminates are studied for fabrication induced residual thermal effects, applied axial strain, and internal pressure loadings. The analysis shows that local curvatures and interlaminar stress concentrations are present near the skin/stiffener joint. Interlaminar stresses are also present along the free edge of the stiffener.

Although the issues are not very controversial, the fusion of both the fields of heat conduction in solids and elasticity which results in the so-called field of dynamic thermoelasticity (both non-classical and classical), dates as far back as Maxwell (1867), and has long been a subject matter of widespread research activity and interest. Although routine thermomechanical problems are primarily influenced by classical effects, issues where non-classical influences may become important are also addressed. To date, numerous applications ranging from defense, aerospace to manufacturing related problems including routine mechanical, civil, nuclear and allied engineering applications influenced by thermal-structural interactions continue to pose significant challenges both from the underlying mechanics and from a computational viewpoint. Herein is first presented an overview of non-classical and classical dynamic thermoelasticity models and equations governing these situations. Subsequently, attention is focused on computational approaches for the modeling and analysis of various classes of problems encompassing thermal-structural interactions which can be broadly classified as: i ) thermally-induced stress wave propagation problems, ii ) thermally-induced dynamic (inertial type) problems, and iii ) the general field of thermal stresses. A variety of illustrative numerical examples encompassing non-classical and classical influences are finally presented to provide an improved understanding of the behavior of thermal-structural problems via effective unified computational developments. This review article contains 142 references.

In nuclear power plants, major tribological problems can occur among the interacting components, such as those in the control assembly, the reactors and the steam generators, due to a combination of impact and sliding motion. Many experimental wear tests have been performed in either room temperature or simulated high pressure, high temperature water environments to study the effects of materials and various operating parameters on wear. Although several successful numerical models are now available for the prediction of dynamic responses during component interaction, only empirical models having limited practical applications are available for wear damage prediction. In recent years, with the advances in tribology and the availability of sophisticated instruments for metallurgical analysis, there have been attempts to develop predictive wear models based on the more fundamental aspects of wear particle formation and detachment. This review article gives a comprehensive account of the past and present work on wear of power plant components. It also includes a brief review of the general wear processes and wear mechanisms. There are 162 references.

In 1992, an overview was presented which summarized the status and progress made in the development of very small, “micro” heat pipes, manufactured as stand alone devices or fabricated as an integral part of silicon wafers. Since that initial review, significant advances have been made in the analysis, fabrication and testing of these devices, for use in a wide variety of applications. Following, is a review of the more recent work in this rapidly emerging field. Included is a summary of the analytical techniques developed, the various proposed methods of fabrication, and a summary of the most current test results achieved to date. Because the fundamental operating characteristics of micro heat pipes larger than 1 mm in diameter are similar to that of conventional heat pipes, this review focuses on the analysis, fabrication, and testing of micro heat pipes with characteristic dimensions of less than 500 μm. Particular emphasis is placed on research, related to the development of arrays of micro heat pipes and flat plate micro heat pipes fabricated as an integral part of semiconductor devices.

The concept of nonlinear normal mode (NNM) is used to study localized oscillations in certain classes of oscillators governed by nonlinear partial differential equations. NNMs are synchronous free oscillations during which all positional coordinates of the system reach their extreme values or pass through the equilibrium position at the same instant of time. Although such motions can be regarded as nonlinear analogs of the linear normal modes of classical vibration theory, not all NNMs are analytic continuations of linear ones. Continuous systems of finite and infinite spatial extent are considered. For periodic assemblies consisting of a finite number of nonlinear structural members, the NNMs are computed asymptotically by solving nonlinear sets of equations possessing regular singular points. Some of the computed NNMs are spatially localized to only a limited number of components of the assembly. The bifurcations giving rise to nonlinear mode localization are examined using the perturbation method of multiple-scales. The implications of nonlinear mode localization on the vibration and shock isolation of periodic flexible structures are discussed. In particular, localized NNMs lead to passive motion confinement of disturbances generated by impulsive loads. Finally, the concept of NNMs is extended to analytically study standing waves with spatially localized envelopes in a class of nonlinear partial differential equations defined over infinite domains. It is shown that NNM-based methodologies can be an effective tool for analyzing such motions.

For functional or aesthetic reasons, many a structural system is designed to be spatially periodic; namely, it is composed of identical sub-units which are connected to form a spatially periodic pattern. The main construction of the hull of a ship, the fuselage of an aircraft, and a space antenna are examples. Such a structure possesses interesting dynamic properties. However, due to material, geometric and manufacturing variabilities, an ideally periodic structure does not exist. The departure from the ideal designed configuration is known as disorder, which can cause drastic change in the dynamic behavior. The present paper gives a review of some recent works on wave propagation and frequency response of disordered periodic structures, of interest to researchers on vibration and noise control.

A numerical study of dynamic instabilities and vibrations of mechanical systems with friction is presented. Of particular interest are friction-induced vibrations, self-excited oscillations and stick-slip motion. A typical pin-on-disk apparatus is modeled as the assembly of rigid bodies with elastic connections. An extended version of the Oden-Martins friction model is used to represent properties of the interface. The mechanical model of the frictional system is the basis for numerical analysis of dynamic instabilities caused by friction and of self-excited oscillations. Coupling between rotational and normal modes is the primary mechanism of resulting self-excited oscillations. These oscillations combine with high-frequency stick-slip motion to produce a significant reduction of the apparent kinetic coefficient of friction. As a particular study model, a pin-on-disk experimental setup has been selected. A good qualitative and quantitative correlation of numerical and experimental results is observed.