| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 857791 | Procedia Engineering | 2014 | 8 Pages |
A novel experimental system involving three bars in parallel that permits C(T) specimens to be subjected to both applied and residual stresses. The system also allows the effects of elastic follow-up to be considered. The C(T) specimen lies within the centre bar, surrounded by two outer bars. The complete system is preloaded to create residual stresses in the structure, and then externally loaded. Two sets of systems are created, one with low elastic follow-up, the second with a high value. In addition to combined loading tests, conventional load controlled tests were conducted on C(T) specimens to act as a reference condition.The mechanical behaviour of the system is compared with finite element simulations and simple models. It is found that the time for the crack to initiate increases in the case of combined loading conditions compared to load controlled conditions at the same total reference stress. The longer initiation times are a consequence of the relaxation and redistribution of the residual loads in the structure. The initiation time is also a function of the elastic follow- up.
