Features of heating of a porous medium containing a liquid by an acoustic field

A mathematical model of the problem of heating a porous medium containing a liquid by an acoustic field is presented. Assuming that the main mechanism that converts the energy of the wave field in a porous medium into heat is the force of viscous friction between the saturating liquid and the skeleton, the function of a volumetric heat source for the process of heating a porous medium using an acoustic field is constructed. The dependences of the power of a heat source on the parameters of the wave field and the parameters determining the state of a porous medium are analyzed.

Thermal Finite Element Modelling of the Laser Beam Welding of Tailor Welded Blanks through an Equivalent Volumetric Heat Source

In last decades, several numerical models of the keyhole laser welding process were developed in order to simulate the joining process. Most of them are sophisticated multiphase numerical models tempting to include all the several different physical phenomena involved. However, less computationally expensive thermo-mechanical models that are capable of satisfactorily simulating the process were developed as well. Among them, a moving volumetric equivalent heat source, whose dimensions are calibrated on experimental melt pool geometries, can estimate some aspects of the process using a Finite Element Method (FEM) modelling with no need to consider fluid flows. In this work, a double-conical volumetric heat source is used to arrange a combination of two half hourglass-like shapes with different dimensions each other. This particular arrangement aims to properly assess the laser joining of a Tailor Welded Blank (TWB) even in case of butt joint between sheets of different thicknesses. Experiments of TWBs made of 22MnB5 steel sheets were conducted in both equal and different thicknesses configurations in order to validate the proposed model. The results show that the model can estimate in a satisfactory way the shape and dimensions of the fused zone in case of TWB made of sheets with different thickness.

A Volumetric Heat Source Model for Thermal Modeling of Additive Manufacturing of Metals

In additive manufacturing of metallic materials, an accurate description of the thermal histories of the built part is important for further analysis of the distortions and residual stresses, which is a big issue for additively manufactured metal products. In the present paper, a computationally volumetric heat source model based on a semianalytical thermal modeling approach is proposed. The proposed model is applied to model the thermal response during a selective laser melting (SLM) process. The interaction between the laser and the material is described using a moving volumetric heat source. High computational efficiency can be achieved with considerable accuracy. Several case studies are conducted to examine the accuracy of the proposed model. By comparing with the experimentally measured melt-pool dimensions, it is found that the error between the predictions obtained by the proposed model and the experimental results can be controlled to less than 10%. High computational efficiency can also be achieved for the proposed model. It is shown that for simulating the thermal process of scanning a single layer with the dimension of 2 mm × 2 mm, the calculation can be finished in around 110 s.