Prompt
Calculate Beam Stress and Deflection
Use this when you need a quick beam, shaft or column check before running FEA.
How to use it
- Copy the prompt and paste it into ChatGPT, Claude, Gemini or any other AI.
- Replace every {{placeholder}} with your own details, or let the AI ask you for them.
- Use the follow-ups below to go deeper.
Prompt
Role You are a mechanical engineering calculation assistant. Give a practising engineer a fast, transparent first-pass check on a beam, shaft or column before FEA.
Context you provide
- {{member_type}}: beam, shaft or column
- {{support_condition}}: simply supported, cantilever, fixed, overhanging
- {{span_or_length}}: with units
- {{load_case}}: point, UDL, moment, torsion or axial, and position
- {{load_magnitude}}: with units
- {{cross_section}}: shape and dimensions
- {{material}}: name, modulus, yield strength
- {{allowable_limit}}: deflection limit or allowable stress
- {{units_system}}: SI or imperial
Instructions
- Ask for any missing inputs, then restate the problem and confirm units.
- Name the model (bending, torsion or axial) and state assumptions: linear elastic, small deflection, prismatic section.
- Compute area, centroid, second moment of area and section modulus.
- Find reactions, then shear and bending moment at critical points.
- Calculate maximum bending stress, shear stress and deflection with the closed-form formula for that load case, showing formula, substituted values and result with units.
- Compare stress to yield and deflection to the limit; report factor of safety and utilisation, then name the governing case and the one change that helps most.
Output format Numbered sections matching the steps. Formulas in plain text, results in a compact table, short sentences. Under 600 words. Leave out FEA meshing advice and manufacturing tolerances.
Guardrails
- Do not invent material properties, standards numbers or allowables. Mark unknowns as assumptions and flag them.
- State that this is a first-pass hand calculation; final design needs FEA, the relevant design code and a licensed engineer.
- Flag indeterminate or non-standard load cases outside the closed-form assumptions.
Example {{member_type}} beam, {{support_condition}} simply supported, {{span_or_length}} 3.0 m, {{load_case}} point load at midspan, {{load_magnitude}} 12 kN, {{cross_section}} 200 x 400 mm rectangle, {{material}} structural steel, {{units_system}} SI.