This calculator evaluates the selected reciprocating mass at top dead centre for a constant-speed inline slider-crank. TDC acceleration is ω²r(1+r/L), inertia magnitude is ma, and nominal selected-area stress is F/A. It does not predict total connecting-rod load or fatigue life.
How actuator stroke affects Solid End Connecting Rod Mechanism
With solid end connecting rod mechanism, the motion profile matters. A linear actuator gives direct extension and retraction, but the output linkage may still create non-linear speed, changing mechanical advantage, and end-of-travel loads.
For structural members, the actuator load should be applied through brackets that do not introduce unintended bending. Check both static load and the extra load created when the mechanism starts, stops, or binds.
The mechanism may also change speed as the linkage angle changes. A constant actuator extension speed does not always create constant output speed, so timing should be checked at the actual output point.
- Map actuator stroke to the actual output travel before choosing a model.
- Check for binding, changing leverage, and peak load near the ends of travel.
- Decide whether timed motion is acceptable or position feedback is required.
For a FIRGELLI design review, calculate the load case with the FIRGELLI actuator force calculator and plan the switching or controller arrangement with the linear actuator wiring diagram generator. If an actuator or cylinder is already installed, the linear actuator replacement finder helps keep the comparison tied to real dimensions.
Solid-End Connecting Rod · TDC Reciprocating-Inertia Ledger
Explore TDC reciprocating-inertia arithmetic without treating it as total connecting-rod load or fatigue qualification.
Equation Used
- The slider-crank is inline.
- Crank speed is constant.
- The selected reciprocating mass is lumped at the slider.
- The selected eye area is a nominal uniaxial comparison area.
- Gas pressure, rod distributed mass, friction, bearing loads, stress concentrations, fatigue, buckling and safety are excluded.
The former peak-tension and load-reversal labels are narrowed to TDC inertia magnitude and shaft-cycle frequency.
Inline slider-crank reference
The animation enforces exact crank radius, connecting-rod length and an axial slider. The output ledger is limited to the selected reciprocating mass at TDC.
What the calculator determines
Select speed, reciprocating mass, stroke, rod length and a nominal eye area. The calculator reports TDC reciprocating acceleration, inertia magnitude, nominal F/A stress and shaft-cycle frequency.
TDC reciprocating-inertia identities
r=S/2; ω=2πN/60; aTDC=ω²r(1+r/L); Fi=maTDC; σnom=Fi/A; f=N/60.
Selected-input example
At 1000 rpm, m=0.5 kg, S=76 mm, L=152 mm and A=80 mm², the ledger reports the TDC reciprocating-inertia magnitude and nominal selected-area stress only.
Inertia ledger, not rod design
Gas pressure, distributed rod inertia, angularity forces, bearing loads, stress concentration, buckling, material, fatigue, lubrication and overspeed are excluded. Those can dominate a real rod design.
Questions
Is the output total peak tension?
No. It is the selected reciprocating mass times TDC acceleration; gas and rod-body loads are absent.
Does F/A qualify the eye?
No. It is nominal selected-area stress without stress concentration, contact or fatigue analysis.
References & Further Reading
- Wikipedia contributors. Connecting rod. Wikipedia
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