The rod looked right on the drawing. Then we loaded it.

1. FAIL · LC2The small-end eye is short in tension: 395.4 MPa, factor of safety 1.80.

   The 5 mm wall around the Ø18 bore bends as the pin pulls. A curved-beam hand check gives about 390 MPa, so this is the part, not the mesh. PCX-ENG-001 asks for 2.0.

2. PASS · LC1Firing peaks where the oil hole breaks into the web pocket: 267.9 MPa, factor of safety 2.65.

   The Ø3 drilling leaves thin walls in a 5 mm web. It passes, but it is why the web could not be thinned.

3. OPENBuckling and fatigue were not judged.

   This seat has SOLIDWORKS Simulation Standard, so the solver refused the buckling study, and the report says so rather than skipping it. A con rod is fatigue-critical; a static pass is not fitness for service.

• small end bore111% LC2-inertia
• small end102% LC2-inertia
• oil hole96% LC2-inertia
• blend small end78% LC2-inertia
• pocket floors76% LC1-firing
• web69% LC1-firing
• pockets66% LC1-firing
• pocket corners66% LC1-firing
• shank47% LC2-inertia
• blend big end33% LC1-firing

1. 01

   Write the study once

   Loads, fixtures and faces go in a study file. Faces are picked by the feature that made them and their shape, with an expected count, so a model change cannot quietly move a load.

2. 02

   Run it on a copy

   The agent starts its own hidden SOLIDWORKS, copies the part, removes the bearing cap from the copy and runs each load case in SOLIDWORKS Simulation. The original is never saved.

3. 03

   Judge it against the standard

   Each result is checked against a written standard: factor of safety on yield and ultimate, deflection, and elements through the thinnest wall. Anything it cannot measure is marked open, never passed.

4. 04

   Find the idle material

   Stress is read on the faces each feature made. A feature working well below the allowable stress is a place to take material out; one above it needs more.

5. 05

   Change, rebuild, re-run

   It changes only dimensions the study allows, within stated bounds. If the model will not rebuild it tries half the step, then gives up and says so.

6. 06

   Report and compare

   Every run is a results bundle. The ParaCrux app turns one into a printable report, or several into a comparison, in your own template.

1. V1 · 575.7 g · passes PCX-ENG-001

   • Small-end eye diameter: 28 → 31 mm
   • Shank width at the big end: 24 → 22 mm
   • Bolt boss depth: 20 → 18 mm
   The agent's reasons

   D2@SK-SMALL-END to 31 mm: SMALL-END-BORE reaches 395 MPa in LC2-inertia, 111% of the allowable stress. Add material here.

   D1@SK-SHANK to 22 mm: Its busiest feature, SHANK, works at 47% of the allowable stress. Material here is mostly idle.

   D1@BOLT-BOSSES to 18 mm: Its busiest feature, M8 CBORE, works at 22% of the allowable stress. Material here is mostly idle.

2. V2 · 568.6 g · passes PCX-ENG-001

   • Small-end eye diameter: 28 → 31 mm
   • Shank width at the big end: 24 → 22 mm
   • Bolt boss depth: 20 → 17 mm
   The agent's reasons

   D1@BOLT-BOSSES to 17 mm: Its busiest feature, MIRROR M8 CBORE, works at 22% of the allowable stress. Material here is mostly idle.

Rejected: Big-end outer diameter — the model would not rebuild at that size, so the change was dropped rather than forced.

The trade it made. The narrower shank lets the rod shorten more under firing: 0.054 mm became 0.088 mm. That is inside the 0.1 mm limit, but it uses 88% of it. Set the deflection limit to 0.08 mm in the table above and both redesigns fail it.

• Design loads are assumed for a single-cylinder engine with a Ø38 crankpin and Ø18 gudgeon pin: 28 kN peak firing compression, 14 kN peak inertia tension at overrun. Replace them with measured engine data before relying on the result.
• Pin loads are bearing loads with a sinusoidal distribution over the loaded half of each bore.
• The rod half of the big-end bore is fixed for the firing case. The two bolt-head seats are fixed for the inertia case. Rigid fixtures raise stress next to them, so stress is evaluated outside a 3 mm zone and the unfiltered peak is reported separately.
• Linear elastic, small displacement, room temperature, no bolt preload, no press-fit of the small-end bush.
• Material properties are read from the SOLIDWORKS material library entry assigned to the part.
• The solver refused this study type (swsRunAnalysisErrorAuthorizationFailed). Buckling needs a SOLIDWORKS Simulation Professional or Premium licence.