A fatigue testing method of wet cylinder liner of diesel engines

It has been agreed to call the loads changing with time and acting in most varied constructional arrangements as well as the stresses accompanying them changeable or cyclic. Changeable stresses produce in the material a very complex entanglement of phenomena and changes depending on the value of those stresses and on the number of cycles. These are fatigue phenomena and changes. They develop successively till the element has been destroyed. This is called the element material fatigue. Thus changing loads and stresses are also called fatigue loads and stresses. The purpose of the presented work was to develop a method of comparative investigations for wet replaceable sleeves in direct contact with coolant that have been submitted to technological treatment of sub-edge zone material strengthening. The source of loads is a cyclically occurring normal component of gas and mass forces in the cylinder. The frequency of changes is a derivative of the number of strokes in the engine run and of the rotational speed of the crankshaft. Fatigue loads can be the reason why cylinder liner cracks in the edge zone. The results of the fatigue testing of the technological process of strengthening the cylinder lines sub-edge zone on crack sensitivity shows differences in the behaviour of particular samples, depending on the parameters of strengthening. The fatigue testing method can be used to evaluate the technological process of cylinder liner.