Resumo em Inglês:

Abstract To study the propagation and evolution of one-dimensional elastoplastic waves within the system under rectangular, trapezoidal, and half-sine incident waves, leveraging elastoplastic incremental wave theory and numerical simulation calculations, the research qualitatively investigates the distribution and evolution of the stress field within the specimen, the impact of Bar 2 parameters, and the deformation characteristics of Bar 2 under these three types of incident waves. The findings indicate: Regardingthe overall stress uniformity of Bar 2 during the entire loading phase, the rectangular incident wave is the most effective, while the half-sine and trapezoidal waves are more advantageous for analyzing the stress conditions in Bar 2 during the early loading phase. The diameter and dimensionless density of the specimen significantly influence the stress non-uniformity, showing an approximate negative and positive correlation, respectively.

Resumo em Inglês:

Abstract A common issue with traditional warheads is the presence of a central blind zone when vertically striking targets. In this study, we proposed an axially reinforced warhead with different filler materials at the front end. Through experimental testing and simulations of single-point detonation at the bottom of the axially reinforced warhead, the fragmentation characteristics of the shell at the front end were analyzed, along with the fragment velocity and fragment distribution. The results showed that compared to traditional cylindrical warheads, the axially reinforced warhead filled with explosives or inert filler demonstrated significant improvements in fragmentation characteristics, the quality of the fragments, and the distribution of the fragments. Moreover, the fragment velocities showed greater similarity, and as the density of the inert filler increased, the improvement became more significant. In conclusion, the axially reinforced warhead with inert fillers at the front end produced evenly distributed fragments in the central damage area, which effectively improved the energy utilization of the warhead.

Resumo em Inglês:

Abstract This paper presents the uncoupled anisotropic thermoelasticity formulation for Boundary Element using the Dual Reciprocity Method. The proposed formulation demands two interpolation functions, one for the particular solution of the elastic problem and another to interpolate the derivatives of the thermal field. For the last one, the shape parameter of multiquadric Radial Basis Functions (RBF) was demonstrated to be a problem to be solved. Some polyharmonic RBFs were tested and a modified function was proposed. Singularity at derivatives of some functions made them impossible to be used and some of them demonstrated great sensibility to saturation. The use of internal points was mandatory under temperature fields irregularly distributed. Few polyharmonic functions were suitable to be used for thermoelasticity and low order functions presented reliable solutions, with the proposed modified RBF presenting slightly better performance over the previously used function.