Alleviating Deformation Of Shell-Type Structures By Using Piezoelectric Ring Stiffeners

• Published in: International journal of modelling & simulation Vol. 19; no. 2; pp. 205 - 212
• Main Authors: Shen, Ji Y., Human, Meldon, Sharpe, Lonnie
• Format: Journal Article
• Language: English
• Published: Anaheim, CA Taylor & Francis 01.01.1999; Calgary, AB Acta Press; Zürich
• Subjects: Deformation alleviation; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Physics; ring stiffener; smart materials and structures; Solid mechanics; Static elasticity; Static elasticity (thermoelasticity...); Structural and continuum mechanics; thin-walled structures; Piezoelectric sensor; Active system; Ring; Thin shell; Strain control; Cylindrical shell; Modeling; Structural analysis; Gravity; Internal pressure
• ISSN: 0228-6203; 1925-7082
• DOI: 10.1080/02286203.1999.11760203

Shell-type structures have found wide applications in civil and aeronautical/aerospace industries. Stringer-stiffeners and ring-stiffeners are commonly used to enhance the stability of shell-type structures. The main subject discussed in this paper, however, is how to alleviate deformation of thin-walled shell-type structures by using piezoelectric ring-stiffeners bonded to the surface of the shell. Their function is realized not only through their own strength, but more importantly through their electric-induced strain, and therewithal, the induced pressure on the surface of the shell, which may produce an adjustable deformation to counteract the deformation caused by external loading. The study of embedded or surface mounted piezoelectric materials in structures has received considerable attention in recent years. The reason is that it may be possible to create certain types of structures capable of adapting to or correcting for changing operating conditions. It is assumed in this paper that the external wall is rigid, and the internal shell with a number of piezoelectric ring-stiffenere is simply supported at its two ends to the rigid external casting. A set of conventional linear partial differential equations defining deformations of a cylindrical shell is accepted. The method of superposition is used to obtain a global solution which consists of contributions from various loading conditions, such as, deformation caused by gravity, deformation caused by internal pressure, and deformation caused by piezoelectric ring-stiffeners. The piezoelectric ring-stiffeners are considered to be made of a β-phase polymeric piezoelectric polyvinylidene fluoride. The coupling effect between mechanical deformations and the charge equations of electrostatics is ignored in this paper. A thin-walled cylindrical shell is designed for computer simulation. Seventeen piezoelectric ring-stiffenere are uniformly disposed along the length of the shell, and perfectly bonded at its outer surface. The deformations along two generatrices of the shell are computed to demonstrate the effect of alleviation. The results show that the effect of alleviation is significant. The maximum deformation is decreased by nearly 70%. The deformed area, which is an important indicator of energy of defoimation, is decreased by almost 80%.