Occurrence of spurious mechanisms in computations of strain‐softening solids

The behaviour of cracked finite elements is investigated. It is shown that spurious kinematic modes may emerge when softening type constitutive laws are employed. These modes are not always suppressed by surrounding elements. This is exemplified for a double‐notched concrete beam and for a Crack‐Line‐Wedge‐Loaded Double‐Cantilever‐Beam (CLWL—DCB). The latter example has been analysed for a large variety of finite elements and integration schemes. To investigate the phenomenon in greater depth an eigenvalue analysis has been carried out for some commonly used finite elements.