หวย@ใบเขียว@ชุด 3 ตัว ประจำงวดวันที่ 16/04/2562
Proper design of compression and extension springs requires a knowledge of both the potentials and the limitations of available materials, together with simple formulas. Since spring theory is normally developed on the basis of spring rate (or gradient), the formula for spring rate is the most widely used in spring design.
from: http://ezinearticles.com/?Aerospace-Springs-Design-and-Development&id=3154928
