![]() Sellen, Stephan ![]() ![]() in Fatigue and Fracture of Engineering Materials and Structures (2015) The following paper is intended to improve the fatigue behaviour of a complex aluminium valve geometry under high internal cyclic pres sure loading. The autofrettage process helps to increase the f atigue ... [more ▼] The following paper is intended to improve the fatigue behaviour of a complex aluminium valve geometry under high internal cyclic pres sure loading. The autofrettage process helps to increase the f atigue durability and a simple, but efficient design method for this proces s is deployed. Based o n non-linear material’s behaviour, fin ite eleme nt simulations of t he crack-free geometry help to determine the minimum and maximum autofrettage pressure to be used, without iterative crack simulations , which would require higher computational effort. Material tests under inverse plastifications were performed in order to determine the correct material model. The derived design method was validated with simplified specimens subjected to different autofrettage pressure levels and su bsequent cyclic fatigue tests. [less ▲] Detailed reference viewed: 249 (25 UL)![]() ; Maas, Stefan ![]() in Fatigue and Fracture of Engineering Materials and Structures (2015) Threaded connections in an aluminium valve body under high internal swelling pressure are investigated. A static straining process called autofrettage leads to an improved fatigue behaviour of the ... [more ▼] Threaded connections in an aluminium valve body under high internal swelling pressure are investigated. A static straining process called autofrettage leads to an improved fatigue behaviour of the aluminium component, while normally the threaded connections are unloaded during this autofrettage. But by unloading the thread during autofrettage the first loaded thread flank became the weakest point of this valve component. This effect is analyzed with non-linear finite element simulations, FKM guideline for fatigue assessment and by experimental testing. The analytical and experimental parts match very well and it can be shown that a well-designed autofrettage without unloading the threaded connection is helpful for the aluminium thread and extends its fatigue lifetime, as compressive residual stresses and an equalized stress distribution over the thread flanks can be generated. Finally different materials were chosen for the plug or screw and this effect for cyclic loading is shortly analyzed. [less ▲] Detailed reference viewed: 210 (16 UL)![]() Sellen, Stephan ![]() ![]() ![]() in Proceesings Nafems deutschsprachige Konferenz '12 (2012, May 08) Detailed reference viewed: 143 (15 UL) |
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