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| − | ===6.4.7 Contact Spring Calculations===
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| − | <figure id="fig:One side fixed contact bending spring">
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| − | [[File:One side fixed contact bending spring.jpg|right|thumb|One side fixed contact bending spring]]
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| − | </figure>
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| − | The influence of the dimensions can be illustrated best by using the single side fixed beam model <xr id="fig:One side fixed contact bending spring"/> (Fig. 6.20). For small deflections the following equation is valid:
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| − | :<math>F = \frac{3 \cdot E \cdot J}{L^3} </math>
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| − | where J is the momentum of inertia of the rectangular cross section of the beam
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| − | :<math>J = \frac{B \cdot D^3}{12}</math>
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| − | For springs with a circular cross-sectional area the momentum of inertia is
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| − | :<math>J=\pi D^4/64</math>
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| − | :<math>D= Durchmesser</math>
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| − | To avoid plastic deformation of the spring the max bending force σ<sub>max</sub> cannot be exceeded
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| − | :<math>\sigma_{max} = \frac{3 \cdot E \cdot D}{2L^2}\cdot_{max}</math>
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| − | The stress limit is defined through the fatigue limit and the 0.2% elongation limit resp.
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| − | :<math>\times_{max} = \frac{2 \cdot L^2}{3 \cdot D \cdot E}R_{p0,2}</math>
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| − | <br />and/or<br />
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| − | :<math>F_{max} = \frac{B \cdot D^2}{6L}R_{p0,2}</math>
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| − | <li>'''Special Spring Shapes'''</li>
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| − | <ul>
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| − | <li>'''Triangular spring'''</li>
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| − | Deflection
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| − | :<math> \times = \frac{F}{2 \cdot E \cdot J}L^3</math>
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| − | :<math>= \frac{6 \cdot F}{E \cdot B}\cdot \frac{L^3}{D^3}</math>
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| − | Max. bending force
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| − | :<math>\sigma_{max}= \frac{18 \cdot F \cdot L}{B \cdot D^2}</math>
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| − | <li>'''Trapezoidal spring'''</li>
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| − | Deflection
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| − | :<math> \times = \frac{F}{(2 + B_{min} /B_{max})}\times \frac{L^3}{E \cdot J}</math>
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| − |
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| − | :<math>\times= \frac{12 \cdot F}{(2 + B_{min} /B_{max})}\times \frac{L^3}{E \times B \times D^3}</math>
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| − | Max. bending force
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| − | :<math>\sigma_{max}= \frac{18 \cdot F \cdot L}{(2 + B_{min} /B_{max}) \cdot B_{max} \cdot D^2 }</math>
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| − | </ul>
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| − | ==References==
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| − | [[Application Tables and Guideline Data for Use of Electrical Contact Design#References|References]]
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