Design, fabrication, and testing of a multiple-actuation shape memory alloy pipe coupler

Abstract

Shape memory alloy pipe couplers use the shape memory effect to apply a contact pressure onto the surface of the pipes to be coupled. In the current research, a shape memory alloy pipe coupler is designed, fabricated, and tested. An in-house developed NiTi alloy is used for the coupler. The coupler is initially designed using finite element as well as analytical modeling to accommodate the required actuation temperature and contact pressure properties. The coupling pressure is then measured using strain gages mounted on the internal surface of an elastic steel ring. The thermal actuation response of the coupler is measured under both stressed and stress-free conditions. In addition, the state of anisotropy is investigated in the coupler by characterizing samples in the longitudinal and transverse directions. The NiTi coupler demonstrates a multiple-actuation response and a high contact pressure. The results show no change in transformation temperatures with respect to two perpendicular transverse and longitudinal directions. However, the material can undergo higher transformation strains in the longitudinal direction.

On the replacement of steel by NITINOL as coupling agent in automobile shaft

“…Researchers have developed finite element analysis of the NiTi coupling considering actuation temperature and contact pressure and measured the same experimentally through a strain gauge installed at the inner surface of the coupling. The finite element analysis results showed an excellent match with experimental plots (Tabesh et al 2018;Chen et al 2020). The installation of SMA coupling is quite simple and convenient but there are certain procedures to be followed to obtain desired shape memory effect (Broyles and Jervis 1973).…”

“…The product was a line of 3000 psi hydraulic coupling. It was commercialized, and over 3 million couplings were put to service in the year 1971 (Tabesh et al 2017). After a decade, SMA coupling became widely popular, and in 1974, it was used as connectors in the navigation system of the Trident missile.…”

Finite strain constitutive modeling for shape memory alloys considering transformation-induced plasticity and two-way shape memory effect

“…For instance, it allows for mounting and dismounting of SMA-based connectors and couplers strain Figure 1: Evolution of the summation of transformation and TRIP strain in the loading direction for a notched NiTi plate subjected to thermal cycling under constant load. Referenced from Wheeler (2017). in an easy procedure by just heating and cooling without pre-stressing (Niccoli et al 2017, Tabesh et al 2018). (iii) The last major contribution of this work is the consideration of stress-dependent TRIP evolution under multiaxial stress state.…”

“…in an easy procedure by just heating and cooling without pre-stressing (Niccoli et al 2017, Tabesh et al 2018). (iii) The last major contribution of this work is the consideration of stress-dependent TRIP evolution under multiaxial stress state.…”

Evolution of multiple Martensite variants in a SMA thick-walled cylinder loaded by internal pressure

“…In order to exploit the full potential of SMA coupling systems, it becomes essential to estimate the stress distribution within these components accurately. Severe stresses may develop during the production stage or the installation of SMA coupling and may cause unexpected mechanical deformation, damage and failure or just loss of efficiency ( Tabesh et al, 2013( Tabesh et al, , 2017. To avoid such technological problems, it becomes necessary to predict the me-E-mail addresses: enrico.radi@unimore.it , eradi@unimore.it chanical stresses originated in SMA connections during each step of their production and installation.…”