MP-27 · JOINTS AND FASTENERS
Bolted Joint External Load
Screen how an external axial load is shared between a preloaded bolt and clamped joint using user-entered bolt and joint stiffness.
Preliminary design support. Your inputs and results stay in this browser.
WHAT THIS SCREEN ANSWERS
A preloaded bolted joint does not usually place the entire external axial load directly into the bolt. The bolt and clamped members act as elastic springs, sharing additional load according to their relative stiffness. This screen makes that relationship visible so a joint is not evaluated from preload and external load as unrelated numbers.
Enter initial preload, external axial load, bolt stiffness, and joint stiffness. MechPlane calculates the load fraction added to the bolt, the remaining clamp load, and a simple separation threshold. If external load is zero, the preload state is preserved. The stiffness values remain explicit because joint geometry and materials determine them.
The simple model assumes a centered axial load and elastic behavior. Real joints can include eccentricity, bending, multiple fasteners, interface slip, embedment, gasket relaxation, thermal expansion, yielding, thread effects, and repeated fatigue loading. Those features can materially change how load is distributed and when separation occurs.
Use this page to understand the load path before more detailed joint work. Confirm actual joint geometry, fastener layout, bolt and member stiffness, target preload, external load path, fatigue, tightening method, and applicable standards. Do not use a simple stiffness ratio as proof of joint integrity or safety.