1 Development of fillets and location of nuts in highly fatigue loaded bolts. Andrei Lozzi 2014 Bolts & nuts 4460

2 Clearance bolt hole Washer dia Max clamped circle dia at midplane

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Article from Volvo on new head bolts stiffness calculation 5

Coventry Climax, 2 liters 4 cyl, 62 The ‘head’ of this engine is removable. To seal the combustion products an even pressure has to be maintained all around the interface between the cylinder block and the head. By this sort of strategy the conical compression zones generated by the pretension has space to spread from the middle of the cylinder block, to all around the top of the cylinder and meet similar cones coming from the head. To achieve this the studs begin half way through the cylinder block and extend all the way to the top of the engine. Each cylinder has 4 bolts equally disposed around its periphery. Cylinder head Interface head to cylinder block. Cylinder head hold-down studs 6

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The effect of fillets and bolt shank cross-section on fatigue strength 8

The effect of the reduction of the bolt shank cross-section by inserting fillets at the start of the threads. Note these results are qualitative, they cannot indicate qualitatively the improvement in fatigue strength, as defined in our texts. 9

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