Solution of the Problems of Stability of Laminated Plates with Holes by the Method of R-Functions

Physical Ultrasonics of Composites is a rigorous introduction to the characterization of composite materials by means of ultrasonic waves. Composites are treated here not simply as uniform media, but as inhomogeneous layered anisotropic media with internal structure characteristic of composite laminates. The objective here is to concentrate on exposing the singular behavior of ultrasonic waves as they interact with layered, anisotropic materials, materials which incorporate those structural elements typical of composite laminates. This book provides a synergistic description of both modeling and experimental methods in addressing wave propagation phenomena and composite property measurements. After a brief review of basic composite mechanics, a thorough treatment of ultrasonics in anisotropic media is presented, along with composite characterization methods. The interaction of ultrasonic waves at interfaces of anisotropic materials is discussed, as are guided waves in composite plates and rods. Waves in layered media are developed from the standpoint of the "Stiffness Matrix", a major advance over the conventional, potentially unstable Transfer Matrix approach. Laminated plates are treated both with the stiffness matrix and using Floquet analysis. The important influence on the received electronic signals in ultrasonic materials characterization from transducer geometry and placement are carefully exposed in a dedicated chapter. Ultrasonic wave interactions are especially susceptible to such influences because ultrasonic transducers are seldom more than a dozen or so wavelengths in diameter. The book ends with a chapter devoted to the emerging field of air-coupled ultrasonics. This new technology has come of age with the development of purpose-built transducers and electronics and is finding ever wider applications, particularly in the characterization of composite laminates.

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Labor Markets and Migration

10.1093/oso/9780198808022.003.0003 ◽

2017 ◽

Author(s):

Philip Martin

Keyword(s):

Labor Markets ◽

Labor Migration ◽

Second Phase ◽

Migration Process ◽

And Migration ◽

R Functions

Labor markets have the three R functions of recruiting workers, remunerating them to encourage them to perform their jobs satisfactorily, and retaining experienced and productive workers. Employers in one country and jobs in another complicate these three Rs, especially recruitment, which is why both employers and workers often turn to private recruiters to act as intermediaries between jobs and workers. Recruiters are most deeply involved in the second phase of the four-phase labor migration process—matching workers with jobs. Indeed, the fact that recruiters rarely visit the workplaces to which they send workers, and do not always expect to send more workers to particular employers, reduces their incentives to make good worker–job matches.

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Buckling of shear-deformable orthotropic laminated plates with elastic restraints

Thin-Walled Structures ◽

10.1016/j.tws.2020.107071 ◽

2020 ◽

Vol 157 ◽

pp. 107071

Author(s):

Philip Schreiber ◽

Christian Mittelstedt ◽

Matthias Beerhorst

Keyword(s):

Laminated Plates ◽

Elastic Restraints ◽

Shear Deformable

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Interlaminar stress analysis of functionally graded graphene reinforced composite laminated plates based on a refined plate theory

Mechanics of Advanced Materials and Structures ◽

10.1080/15376494.2021.1919805 ◽

2021 ◽

pp. 1-13

Author(s):

Qilin Jin

Keyword(s):

Stress Analysis ◽

Plate Theory ◽

Functionally Graded ◽

Laminated Plates ◽

Refined Plate Theory ◽

Interlaminar Stress ◽

Composite Laminated Plates ◽

Reinforced Composite

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Interfacial Morphology and Bonding Mechanism of Explosive Weld Joints

Chinese Journal of Mechanical Engineering ◽

10.1186/s10033-020-00495-7 ◽

2021 ◽

Vol 34 (1) ◽

Author(s):

Tingting Zhang ◽

Wenxian Wang ◽

Zhifeng Yan ◽

Jie Zhang

Keyword(s):

Laminated Composite ◽

Base Plate ◽

Sine Wave ◽

Laminated Plates ◽

Bonding Interface ◽

Interfacial Structure ◽

Bonding Mechanism ◽

Critical Material ◽

Interfacial Morphology ◽

Az31b Alloy

AbstractInterfacial structure greatly affects the mechanical properties of laminated plates. However, the critical material properties that impact the interfacial morphology, appearance, and associated bonding mechanism of explosive welded plates are still unknown. In this paper, the same base plate (AZ31B alloy) and different flyer metals (aluminum alloy, copper, and stainless steel) were used to investigate interfacial morphology and structure. SEM and TEM results showed that typical sine wave, wave-like, and half-wave-like interfaces were found at the bonding interfaces of Al/Mg, Cu/Mg and SS/Mg clad plates, respectively. The different interfacial morphologies were mainly due to the differences in hardness and yield strength between the flyer and base metals. The results of the microstructural distribution at the bonding interface indicated metallurgical bonding, instead of the commonly believed solid-state bonding, in the explosive welded clad plate. In addition, the shear strength of the bonding interface of the explosive welded Al/Mg, Cu/Mg and SS/Mg clad plates can reach up to 201.2 MPa, 147.8 MPa, and 128.4 MPa, respectively. The proposed research provides the design basis for laminated composite metal plates fabrication by explosive welding technology.

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