Abstract:
This paper describes an experimental technique for determining the constitutive equations of damaged borosilicate glass, including both its elastic and plastic behaviors. The method involves testing a pre-damaged cylindrical glass specimen inside a steel sleeve. Measurements of the axial stress and strain of the specimen, along with the hoop strain of the steel sleeve, are recorded. An analytical model is used to interpret this data, assuming the specimen follows a Drucker-Prager plasticity model. This model allows for the determination of the elastic and plastic constants from the slopes of the measured stress-strain curves. The analytical model is verified with numerical simulations using LS-DYNA, confirming the validity of the experimental procedure. The paper also investigates the influence of friction between the specimen and sleeve, finding that a low friction coefficient is acceptable while a high one significantly impacts the results. The study of predamaged glass shows that its elastic constants are similar to intact glass, and that failure does not change its volume. The determined constants can be applied in computations for applications like ballistic penetration.
