Cylindrical helical springs made from rectangular and square section wire and bar. Guide to calculation and design

2015 ◽  
Keyword(s):  
Helical Springs

MECHANICAL BEHAVIOR OF Ni-Ti SMA HELICAL SPRINGS MANUFACTURED BY INVESTMENT CASTING

2017 ◽  
Author(s):  
Paulo César Sales da Silva ◽  
Jackson Simoes ◽  
Carlos Jose de Araujo ◽  
jose joelson de melo santiago
Keyword(s):  
Mechanical Behavior ◽  
Investment Casting ◽  
Helical Springs

Design Nomographs of Compression Helical Springs for Predetermined Reliability Levels

1981 ◽  
Vol 103 (2) ◽  
pp. 268-273
Author(s):  
My Dao Thien ◽  
M. Massoud
Keyword(s):  
Probabilistic Approach ◽  
Design Procedure ◽  
Axial Loading ◽  
Geometric Parameters ◽  
Computer Algorithms ◽  
Mean Values ◽  
Helical Springs ◽  
Reliability Level ◽  
Classical Design ◽  
Mission Success

This paper discusses a probabilistic approach for the design of Compression Closely Coiled Helical Springs subjected to periodic axial loading. The classical design procedure results in deterministic geometric parameters with tolerances normally chosen according to standards without due regard to their effects on the mission success as normally expressed by a reliability level. With the proposed design procedure, the engineer can specify nominal mean values for the geometric parameters and their tolerances according to a predetermined reliability level. Design nomographs are presented to help the engineer, in the early stages of design, to choose between many alternatives. Computer algorithms can easily be written to verify the final or optimum design.

Study of the coupled free vibration of helical springs

AIAA Journal ◽  
1992 ◽  
Vol 30 (5) ◽  
pp. 1443-1447 ◽  
Author(s):  
W. Jiang ◽  
T. L. Wang ◽  
W. K. Jones
Keyword(s):  
Free Vibration ◽  
Helical Springs

Effect of the Material Types on the Fundamental Frequencies of Uniaxial Composite Conical Springs

1999 ◽  
Author(s):  
Vebil Yildirim ◽  
Erol Sancaktar ◽  
Erhan Kiral
Keyword(s):  
Transfer Matrix Method ◽  
Pitch Angle ◽  
Natural Frequencies ◽  
Axial Deformation ◽  
Helical Springs ◽  
Fundamental Frequencies ◽  
Helix Pitch ◽  
Constant Pitch ◽  
Α Helix

Abstract This paper deals with the effect of the material types (Graphite-Epoxies and Kevlar-Epoxy) on the fundamental frequencies of uniaxial constant-pitch composite conical helical springs with solid circle section and fixed-fixed ends. The transfer matrix method is used for the determination of the fundamental natural frequencies. The rotary inertia, the shear and axial deformation effects are taken into account in the solution. The free vibrational charts for each material presented in this study cover the following vibrational parameters: n (number of active turns) = 5–10, α = (helix pitch angle) = 5° and 25°, R2/R1, (minimum to maximum radii of the cylinder) = 0.1 and 0.9, and Dmax/d (maximum cylinder to wire diameters) = 5 and 15. These charts can be used for the design of uniaxial composite conical springs.

Analytical and Numerical Modelling of Shape Memory Alloy Negator Springs for Long-Stroke Constant-Force Actuators

2012 ◽  
Author(s):  
Andrea Spaggiari ◽  
Eugenio Dragoni
Keyword(s):  
Shape Memory ◽  
Mechanical Behaviour ◽  
Volume Ratio ◽  
Constant Force ◽  
Helical Springs ◽  
Finite Element Software ◽  
Spiral Spring ◽  
High Area ◽  
Flat Shape ◽  
Long Stroke

This paper explores the merits of shape memory Negator springs as powering elements for solid state actuators. A Negator spring is a spiral spring made of strip of metal wound on the flat with an inherent curvature such that, in repose, each coil wraps tightly on its inner neighbour. The unique characteristic of Negator springs is the nearly-constant force needed to unwind the strip for very large, theoretically infinite deflections. Moreover the flat shape, having a high area over volume ratio, grants improved bandwidth compared to any solution with solid wires or helical springs. The SMA material is modelled as elastic in austenitic range while an exponential continuum law is used to describe the martensitic behaviour. The mathematical model of the mechanical behaviour of SMA Negator springs is provided and their performances as active elements in constant-force, long-stroke actuators are assessed. The SMA Negator spring is also simulated in a commercial finite element software, ABAQUS, and its mechanical behaviour is estimated through FE analyses. The analytical and the numerical prediction are in good agreement, both in martensitic and in austenitic range.

Sign in / Sign up

Export Citation Format

Share Document