Page 110 - The Mechatronics Handbook

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8

Structures and Materials

8.1 Fundamental Laws of Mechanics
Statics and Dynamics of Mechatronic Systems • Equations
of Motion of Deformable Bodies • Electric Phenomena
8.2 Common Structures in Mechatronic Systems
Beams • Torsional Springs • Thin Plates
8.3 Vibration and Modal Analysis
8.4 Buckling Analysis .
8.5 Transducers
Electrostatic Transducers • Electromagnetic
Transducers • Thermal Actuators • Electroactive
Eniko T. Enikov Polymer Actuators
University of Arizona 8.6 Future Trends

The term mechatronics was first used by Japanese engineers to define a mechanical system with embedded
electronics, capable of providing intelligence and control functions. Since then, the continued progress
in integration has led to the development of microelectromechanical systems (MEMS) in which the
mechanical structures themselves are part of the electrical subsystem. The development and design of
such mechatronic systems requires interdisciplinary knowledge in several disciplines—electronics,
mechanics, materials, and chemistry. This section contains an overview of the main mechanical struc-
tures, the materials they are built from, and the governing laws describing the interaction between
electrical and mechanical processes. It is intended for use in the initial stage of the design, when quick
estimates are necessary to validate or reject a particular concept. Special attention is devoted to the newly
emerging smart materials—electroactive polymer actuators. Several tables of material constants are also
provided for reference.

8.1 Fundamental Laws of Mechanics

Statics and Dynamics of Mechatronic Systems
The fundamental laws of mechanics are the balance of linear and angular momentum. For an idealized
system consisting of a point mass m moving with velocity v, the linear momentum is defined as the
product of the mass and the velocity:

L = mv (8.1)

The conservation of linear momentum for a single particle postulates that the rate of change of linear
momentum is equal to the sum of all forces acting on the particle

˙
L = mv ˙ = ∑ F i (8.2)

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