Checking joints 11-12, 11-12′ (pin joints) with MDESIGN — example

1. Input data and results

Input data

Geometry data

Loading data

Pin material data

Fork material data

Rod material data

Results

Strengths and allowable stresses (pressures)

Meaning

– Material Data: R_m – ultimate strength of the material for the pin (Crossbolt) / the fork (Fork) / the rod (Pole); R_e – yield strength of the rod material (for Pole).

– Allowable Loadings: σ_bzul – allowable bending stress; τ_vorth – allowable shear stress; p_zul – allowable surface pressure for the pin (Crossbolt) / the fork (Fork) / the rod (Pole).

Actual stresses

Meaning

– Building Case (design case)

	Design case 1: pin – fork = clearance fit; pin – rod = clearance fit
	Design case 2: pin – fork = press fit; pin – rod = clearance fit
	Design case 3: pin – fork = clearance fit; pin – rod = press fit

– M_b – bending moment; σ_bvorth – existing (actual) bending stress; τ_vorth – existing shear stress; p_svorth – mean surface pressure between pin and rod (Mean Surf. Pressure (Pole)); p_vorth – mean surface pressure between pin and fork (Mean Surf. Pressure (Fork)).

Actual safety factors

Meaning

– Safeties (safety factors), Building Case (design case), see above.

– S_b – safety factor for bending; S_t – safety factor for shearing; S_ps – safety factor for the surface pressure on the rod (Pole); S_pg – safety factor for the surface pressure on the fork.

General data on the stresses in the rod body

Meaning

σ_w – maximum normal stress in the rod near the pin (Max. Normal Stress); σ_wzul – allowable normal stress of the rod material (Allowable Normal).

2. Checks

The pin joint of tubes 11 and 12 falls under design case 1

Design case 1: pin – fork = clearance fit; pin – rod = clearance fit

Bending strength of the pin

σ_bvorh ≤ σ_bzul; 10.44 < 147 MPa (satisfied),

or

S_b ≥ S_adm; 14.07 > 2 (satisfied).

Shear strength of the pin

τ_vorh ≤ τ_bzul; 10.44 < 98 (satisfied),

or

S_t ≥ S_adm; 35.19 > 2 (satisfied).

Crushing strength in the pin–rod contact

p_svorh ≤ p_zul; 2.63 < 126 (satisfied),

or

S_ps ≥ S_adm; 48 > 2 (satisfied).

Pin–fork contact

p_svorh ≤ p_zul; 2.63 < 126 (satisfied),

or

S_pg ≥ S_adm; 48 > 2 (satisfied).

Note. S_adm is the allowable safety factor (S_adm = 2 was adopted).

Checking the rod

σ_w ≤ σ_wzul; 2.39 < 117.5 (satisfied).