A bracket is held by M12 bolts of property class 8.8 through two 15 mm steel plates. Each bolt carries a 6 kN axial pull and a 2 kN transverse load. This tutorial rebuilds the Bolted bracket example, reads the VDI 2230 results, then overloads the joint in shear and tries three fixes.

The numbers are those of this version of Axomek. To compare: open the Bolted bracket example. It starts a new project from the example in place of yours, so save yours first (the app asks) and come back to it with Switch project (Ctrl+P).

Step 1: add the joint

Start a Blank project and open Bolts in the navigation.
Choose Add a joint. Joint J1 appears.
Set Name to Bracket bolt.
Under Loads per bolt, set Axial working load FA,max to 6000 N and Transverse load to 2000 N.

The other inputs keep their starting values:

Group	Input	Value
Bolt	Thread, Property class	M12, 8.8
	Joint, Head	Through bolt with nut, hexagon head
	Thread friction μG, Head friction μK	0.12, 0.12
	Tightening method, Tool	Torque-controlled, torque wrench (αA 1.6)
Clamped parts	Two plates	15 mm each, steel, E 210 000 MPa, limiting pressure 760 MPa
	Interface diameter DA	40 mm
	Roughness Rz	6.3 µm
Loads per bolt	Plate friction μT	0.15
Load introduction	Load introduction n	0.5

The loads are per bolt. Divide the bracket's loads among its bolts yourself, including the share of any moment.

Step 2: read the results

The results column shows three key results and the checks.

Key result	Value
Tightening torque MA	83.6 N·m (it gives FMzul = 43.1 kN at μG 0.12, μK 0.12)
Preload needed FMmin	21.6 kN; FMmax = 34.6 kN with αA 1.6
Load factor Φn	0.091; the bolt takes 546 N of the 6000 N working load

Check	Value / minimum
Yield (working stress)	1.17 / 1
Fatigue	15.1 / 1.2
Surface pressure	1.29 / 1
Slipping	1.40 / 1.2
Shearing	21.9 / 1.1
Preload reserve FMzul / FMmax	1.25 / 1

All checks pass.

How to read it:

The bolt is tightened to 90 % of its yield strength (ν = 0.9) at the torque MA. With the scatter of a torque wrench, the preload lands anywhere between FMmin and $F_{M \max} = α_{A} \cdot F_{M \min}$ .
Preload needed is the least assembly preload that still clamps after embedding (2.8 kN lost here), with the working load on top. The clamp load must also carry the transverse load by friction: 13.3 kN for 2000 N at μT 0.15.
The joint is much stiffer than the bolt, so only 9 % of the working load reaches the bolt (Φn = 0.091). That is why the fatigue safety is so high: the bolt barely feels the load cycle.
The yield safety is about the working stress of the tightened bolt plus its share of the load; at ν = 0.9 it stays close to 1.

Step 3: raise the shear load

Set Transverse load to 3000 N. Two checks fail:

Check	Value / minimum
Slipping	0.934 / 1.2 (fails)
Preload reserve FMzul / FMmax	0.953 / 1 (fails)

To hold 3000 N by friction the joint needs more clamp load. With αA 1.6 the largest preload this implies, FMmax = 45.2 kN, is above what an M12 8.8 can take at the specified torque (FMzul = 43.1 kN). The bolt is too small for this load with this tool.

Step 4: three fixes

Try each from the state of step 3 (Transverse load 3000 N), then go back with Ctrl+Z.

A. A more precise tool

Set Tool to Precision torque wrench (αA 1.4).

The scatter shrinks, so FMmax falls to 39.6 kN and fits under FMzul. Slipping improves to 1.13, but still fails its minimum of 1.2. Better tightening helps, but it is not enough here.

B. A higher property class

Set Property class to 10.9 (back to the torque wrench).

FMzul rises to 63.3 kN and MA to 122.8 N·m. Slipping passes at 1.57. But Surface pressure now fails at 0.880: the higher preload presses the bolt head into the plate harder than its limiting pressure of 760 MPa allows. You would need a hardened washer or a plate material with a higher limiting pressure.

C. A larger thread

Set Thread to M14 (property class 8.8, torque wrench).

Check	M12	M14
Slipping	0.934	1.39
Preload reserve	0.953	1.27
Surface pressure	1.29	1.45
Yield	1.17	1.17
Fatigue	15.1	19.6

All checks pass, with MA = 133.5 N·m. M16 would give more margin (slipping 2.03), at MA = 205.9 N·m.

The M14 is the simplest fix: it carries the transverse load by friction with the ordinary tool and stays within the plates' limiting pressure.

Going further

Under Eccentricity, describe a bracket whose bolt sits off the load line: the joint can then open at one edge, and the load factor becomes Φen*.
Under Fatigue and thread engagement, give a tapped part's strength to check the engagement length.
Under Temperature, warm the bolt and the plates differently and watch the preload change.