Patent ID: 11880636
Assignee: UNIVERSITA' DEGLI STUDI DI ROMA LA SAPIENZA
Field: Transport (Mechanical engineering)
Classification: CPC B  G  Y | IPC B  G

Claim 0:
1. A design method for manufacturing prestressed shells having tuned bistability, wherein, to determine the appropriate prestress to be applied to the bistable structure/shell, the method comprises the following operating steps:
A). using a clamp, clamping material of a shell by applying a predetermined curvature on a portion of the shell's edge: the prestress which is obtained by imposing the clamp depends on a finite number of design parameters pi={hi=1, 2 . . . ;mi=1, 2 . . . ;c}: hi, mi are the parameters representative of a shape of the initial stress-free configuration of the shell free from external constraints, and of the material while c is the curvature of the clamp;
B). defining a discrete shell model dependent on a small number of configuration parameters qi, (i<5) by projecting the non-linear shell model of Marguerre-von Kármán onto an appropriate finite dimensional space;
C). tracing stability maps in the space of the design parameters by means of the discrete representation of the elastic energy E(qi;pi) thus obtained to determine the number and the shape of the stable equilibrium configurations of the clamped shell, which at each load level correspond to a particular choice of the design parameters;
D). choosing the design parameters providing the necessary prestress to obtain a desired behaviour in terms of project requirements;
whereby obtaining:
designing the shapes that the shell must assume during the loading process according to performance requirements;
establishing critical load levels at which the transition must occur, choosing a point whose corresponding clamped shell has only one stable configuration for F=0, two for F2≤F≤F1 and again one for F>F1;
changing critical transition loads also during the operation of the structure, to fulfill changes in the performance requirements; and
identifying a corresponding optimized shape of the shell when free from constraints.