The Research Ultimate Strength Evaluation Method Of Hull Cabin Structure Based On Grillage Experiment

It is diffic ult t o accurately asses s the residual st rength of damaged hul l structure due t o the ge omet ric nonlinearity and mater ial nonlinearity of da mage r egion, t hus leadi ng the accurac y of t he evaluation res ults cannot be ensured. And the t est data of the scale model method cannot be c onverte d to ship st ructure due to stiffnes s differences and nonlinear conversion relationship be tween the scale model and ship, also t he accuracy of the evaluat ion results needs furt her e xaminati on. Neve r thel ess, the full sc ale test i s hard to be us ed in strength assessment of large ship structure which i s limi ted by l oading c apac ity and testing site. Therefore, i t is desider ate d to de velop a method whic h applies to s trengt h assessment of large damaged hul l st ructure and s hip struc ture protection design.Focusing on stress field, displacement fie ld and ultimate bearing capacity, the arti cle c onducts some resear ch on the influe nce of rot ation at the end face of single deck grillage,pe r for ated single deck grill age and doubl e de ck grillage, and do comparis on and analysis of the relations hip bet ween cabin st ructure and deck grillage in hogging and sagging conditi on, and di scusses the ultimate st rength evaluation method of hull cabin structure based on grillage e xperiment.Main mis sions a nd Conclusions:1 The influence of rotation at the end fac e of single deck grillage, perforated single deck grillage and double deck grillage, whi ch i s focused on structure re sponding and ultimate bearing c apacity, is s tudied in this thes is, and the law of influence of rotation at the end face of deck grillage, whi ch is focused on stress fie ld, displacement field and ul timate bearing capacity is obt aine d.2 The relationship between struc ture responding and ultimate bearing capacity of cabin struc ture and deck grillage under the load i s studied. Conclusions can be drawn as follow:The structure r esponding of deck gr ill age in tension and the deck of cabin in hogging c onditi on are consistent, and the infl uence of rotation at the end face can be ignored when it i nvolves ult imate bea r ing ca pacity research of the deck grillage of cabin struc ture i n tension.The structure r esponding of deck gr ill age pressured and the dec k of cabi n in saggingc onditi on are consistent, and the infl uence of rotation at the end face should be reckon in when it i nvolves ult imate bea r ing ca pacity research of the deck grillage of cabin struc ture pressured.3 The article puts forwa rd the ultimate st rength assessment method of hull structure based on t est of deck grillage for the first time.For the ultimate strength a ssessment met hod of hull structure in hogging condition, the reasonable deck grillage can be selected from c abin structure, t hen the de ck grillage tension test c an be conducted by dir ect displac ement loading met hod, and the displacement field and ul tima te bearing capac ity are obta ined. The ultimat e bearing capaci ty in hogging condition ca n be converted by the relation between the load-displa ceme nt of t he deck grill age and bending moment of c ross s ection.For the ultimate strength a ssessment met hod of hull structure in sagging condition, t he reasonable deck grillage can be selected from c abin structure, t hen the de ck grillage compression t est can be conduct ed by displacement l oading method wit h rotation at t he end face, and the di splacement field a nd ulti mate bearing capacity are obtained. The ul timate bearing capacity i n sagging c ondition can be converted by the relation between the load-displacement of the deck grillage and bending moment of cross section.