PSI - Issue 33

Tatyana Tretyakova et al. / Procedia Structural Integrity 33 (2021) 1013–1018 Author name / Structural Integrity Procedia 00 (2019) 000–000

1014

2

macrofracture. An urgent direction in the field of solid mechanics is the experimental study and theoretical description of the regularities of the spatial-time inhomogeneity of inelastic deformation, the processes of development of defects and destruction, taking into account the influence of the type of complex stress-strain state of the material. It is well known, that in most cases the material during the operation of structures works under conditions of a complex stress state, under complex thermomechanical influences (Wildeman 2017, Tretyakov 2016, Tretyakova 2017). On the other hand, carrying out mechanical tests under a complex stress state is associated with significant methodological difficulties and technical limitations of loading schemes and modes, methods for achieving controlled stress-strain state in the working area of the sample, as well as methods for recording and interpreting the results obtained. This work is aimed at the development of existing techniques and the creation of new scientifically grounded approaches to the experimental study of the patterns and features of inelastic behavior of modern structural metals and alloys based on the use of original specimens with complicated geometry, in the working area of which the required complex stress state is created.

Nomenclature σ stress u

elongation

Young's modulus Poisson's ratio

E

v

2. Experimental procedure To create a complex stress-strain state in the gauge length of the specimen, it is proposed to use cylindrical specimens with a circular groove. Computational and experimental studies of the influence of the geometry of concentrators on the effects of yield delay and jerky flow of Al-Mg alloys under tension of axisymmetric specimens have been carried out. Uniaxial tension of specimens with ring concentrators of various geometries have been implemented. Sample sketches are shown in Fig. 1.

a

b

c

d

Fig. 1. Specimens with ring concentrators of various geometries: groove with a radius of 5 mm (a); groove with an angle of 157 ° and a radius at the apex of 5 mm (b); groove with an angle of 140 ° and a radius at the apex of 5 mm (c); groove with an angle of 140 ° and a radius at the apex of 5 mm (d)