Advanced Extension Spring Design APK

On the internet, Microsoft Store, Google Play Store, Apple App Store, many spring design software, equations, methods, and general design considerations are available. The capability of these software, however, are limited. For serious usage, software from SMI and IST are two of the major applications nowadays. The new Advanced Extension Spring is a comprehensive extension spring design software package. Advanced design method is employed to evaluate all possible configurations to meet various design requirements. This program package analyzes and designs springs on an Android device. Tablet is the most suitable device to run this app.

To design an extension or a torsion spring that works in a given space with required forces or torque, and also accommodate spring ends movement, many different configurations can be adapted to achieve the same requirement:

In a general condition, the given requirements may include the following:
     - Maximum force/torque at a maximum extended spring length/rotation
    - Minimum force/torque at a minimum extended spring length/rotation
    - Minimum spring cycle life.

The environment condition limits the size and shape of the spring.  These geometrical constraints may include:
  - For an extension spring, the relative orientation and minimum hook length and width
of the two hooks, cylindrical body or tapered body
  - For a compression spring, the end constrain and the lateral support conditions
  - The maximum outer coil diameter, minimum inner coil diameter
  - Material to be used

With these requirements and environment constraints, possible choices for a spring may include:
- Wire diameter
- Coil diameter
- Number of coil
- Pretension level, cylindrical body or tapered body (extension spring)
 - Coil body length
- Spring free length, legs relative angle
- Type of material

This computer program finds a range of spring geometrical dimensions that meet the force, torque, life requirements.

SPRING LOADS AND EXTENDED POSITIONS:
The extension spring has an initial tension that is coiled in the spring body so that at free length all coils contact each other. Two extended positions with corresponding loads define the requirement of the spring. The range of loads divided by the range of deflection defines the spring rate. The spring length for the three loading conditions (free length, 1st stage loading, 2nd stage loading), measured from the hook interface points, are used to design the spring.

HOOK CONFIGURATIONS:
The two hooks may be oriented in four configurations.

INITIAL TENSION CRITERIA
The permissible pretension reported by Dr. A. M. Wahl is employed: You may design the spring with initial tension as follows:
Area A (Preferred), Areas A+B (Up to area B of Special Setup), and Areas A+B+C (Up to area C of Maximum Initial Tension.

INPUT PARAMETERS:
Description of this Design: Title
Material type(1-14)
Material Shear Modulus G
Wire diameter adjustment
Coil outer diameter max allowed
Coil inner diameter min required
Minimum hook length, each
Hook Width (mm)
Hook root radius R1 (mm)
Hook root radius R2 (mm)
Hook Orientation: (1,2,3 or 4)
Pretension criteria (1 thru 3)
Stage 1 Length (mm)
Stage 1 Force (N)
Stage 2 Length (mm)
Stage 2 Force (N)
Minimum spring life (cycles)
Wire sizes to be considered (1-all, 2=defined)
Smallest wire Diameter to be considered (mm)
Largest wire Diameter to be considered (mm)
Wire size increment (mm)
Coil size increment (mm)
Tapered cone loop number (each end)
Taper cone ratio

EXTENSION SPRING LIFE
The fatigue life prediction of extension springs has been tested and reported extensively. The modified Goodman Diagram is used in the program.
Also the published material by SAE for life estimation is used.