We present a method for numerical simulation of temperature field of mass concrete with cooling pipes.Cooling pipes are put in conventional concrete element.Contact surface of concrete and cooling pipes is considered as thermal surface in boundary conditions of control equation.And energy dissipating through cooling pipe walls in concrete is brought into conventional functional.A governing equation of finite element method is established for concrete containing cooling pipes with variational principle.A finite element simulation program for three-dimensional transient temperature field is designed.In the program,topology information of cooling pipe mesh can be completed automatically.Cooling pipes can cross concrete elements anywhere which does not increase difficulty of mesh generation.Numerical examples show that the method accurately simulates cooling of concrete.

The diffraction of elastic wave is studied by using Boundary Element Method, and the formulation about elastic wave diffraction is given. For caculating singular integral, a improved numerical method which divides dynamic fundamental solution into singular part and regular part is proposed. Finally examples of P wave and SV wave scatter against circular hole and ellipse hole are discussed.