Study On The Fracture Behavior Of Plain Concrete Beam With V Notch

Due to the design of engineering components and mechanical components need to make the incision type exists in a variety of real-life applications,but at present,there are few researches on the stress field of the sharp notch,most of the previous discussions are straight cracks,which makes the study of related issues become very urgent.At present,the revised strength factor manual at home and abroad only applies to the components with straight cracks,however,the stress intensity factors of components contain incision have not been established.In addition,in the past,the fracture toughness is evaluated by the fracture toughness,so the application of this method requires the guidance of professional personnel,which is often not easy to be applied in practical engineering.In order to simplify the problem,the safety assessment by fracture toughness can be transformed into the safety assessment by failure load.In this paper,two kinds of stress intensity factors are obtained by using the finite element method(FEM)and finite strain energy criterion(V),then,the equivalent relation between the limit state of notch stress intensity factor and the generalized fracture toughness is established,on the basis of it,the theoretical prediction formula is obtained.In order to make the failure mechanism of V type incision component more clearly,the size of the fracture process zone of the specimen contain V notch is measured,To investigate the relationship between the size of fracture process zone and the angle of V type incision,The relationship between fracture process zone size and crack height ratio is also discussed.Finally,the stress intensity factors of V notched specimens are also compared with those of finite fracture mechanics and average strain energy density criterion.In this paper,the work includes: 1)By means of digital image correlation method,the fracture process zone size of five groups of specimens with straight cracks and group V specimens were observed,it were discussed that the change of fracture process zone(FPZ)with the seam height ratio and the V type incision angle,and study the relationship between crack height ratio and the V notch angle with crack load incision.2)Based on the Finite Fracture Mechanics criterion(FEM),the Notch stress fracture factor and the finite distance formula with sharp V type are obtained,thought the failure load of specimen which contain two kinds of special V notch angle,in addition to reference data comparison predicted the failure load of specimens with other angles.In this paper,we made three kind of specimen contain crack height ratio 0.2 ? 0.3 ? 0.4.In addition,the relevant literature data are also compared.3)The effectiveness of the notch stress intensity factor predicted by the two finite fracture mechanics and the average strain energy density criterion is verified by the relevant literature data and experimental data.Based on the Average strain energy densitycriterion(SED)criterion,the Notch stress fracture factor was obtained,thought the failure load of specimen which contain two kinds of special V notch angle,in addition to reference data comparison predicted the failure load of specimens with other angles.