No abstract

At present, directional solidification (DS) made blades are commonly used in high per formance turbine for their better high temperature mechanical, especially in creep prop erties compared with the equiaxed grain (EG) blades made by conventional casting method. To predict DS blades' fatigue life accurately, one of the practical ways is to con duct tests on full-scale blades in a laboratory!bench environment. In this investigation, two types o f full scale turbine blades, which are made from DZ22B by DS method and K403 by conventional casting method, respectively, were selected to conduct high tem perature combined low and high cycle fatigue (CCF) tests on a special design test rig, to evaluate the increase o f fatigue life benefitted from material change. Experimental results show that different from EG blades, DS blades' fracture section is not located on the position where the maximum stress point lies. By comparing fatigue test results of the two types of blade, it can be found that the fatigue properties among different regions o f the DS blade are different, and its fatigue damage is not only related to the stress field, but also affected by different parts material's fatigue properties.

No abstract

No abstract

A new type of tunable bistable metamaterial (TBM) is proposed which is made by embedding magnets into the flexible cellular bistable materials with double tilted beams. To find out the effect of magnets on the mechanics of TBM, several samples are fabricated and magnets with different residual flux density, which is used to describe the magnetic field strength, are embedded. Quasi-static uniaxial compression tests are performed and the results show that the bistability of the TBM is successfully adjusted by embedding magnets. Furthermore, both numerical and analytical simulations are carried out to further understand the bistable property and energy absorption ability of the proposed metamaterial.