Ryszard Buczkowski

Many gas companies build and operate gas distribution system in the city country and around the world. The traditional open-cut excavation requires the ground to be broken up by heavy equipment, the soil and asphalt need to be removed. Traditionally, a technician requires a minimum of 60 cm by 180 cm excavation to perform routine procedures. Often the trench must be temporarily supported using some type of shoring before a utility worker can enter the hole to perform the repairs to the utility pipe. This process is costly, time consuming, dangerous and is inconvenient to traffic patterns. We propose a new solution called keyhole technology which minimizes labor and restoration costs compared with conventional practices. In our design, the same construction and maintenance procedures can be accomplished through a 45 cm diameter circular holes above the utility pipe to be repaired. However, specially designed, long handled tools that operate remotely are necessary. This process is more cost-efficient, less dangerous and less disruptive to traffic patterns because there is no additional milling and overlaying of the road. The small hole requires little replacement materials to fill the hole. Because the concept is relatively new to the public utility sector, there is a lack of equipment/tools available that could perform the required services. The finite element analyses using commercial package Abaqus will be employed to obtain the force needed to close the pipe. As a final example, we will show the topology optimization of squeeze–off tool as the act of an iterative process. The correctness of the numerical calculations was verified by a pipe compression experiment on Instron 8850 testing machine.

We get some insight into the new construction and maintenance operations so called keyhole technology which minimizes labour and restoration costs compared with conventional practices. Because the concept is relatively new to the public utility sector, there is a lack of equipment/tools available that could perform the required services. The finite element analyses using commercial package ABAQUS will be employed to obtain the force needed to close the pipe. As a final example we will show the topology optimization of squeeze–off tool as the act of an iterative process.

The aim of the work is to show both the similarities and differences in the formation of deformation-induced roughness in contact compression in the presence of oil and the problem of free surface roughing during uniaxial stretching in a plastic area. The relationships between changes in the roughness are caused by the deformation of the sample and the viscosity of oil at the contact area. It has been shown that normal contact loading with the presence of oil initially leads to an increase in surface roughness, then to its smoothening. The results of the experimental research have been compared with numerical simulation made using FSI (Fluid Structure Interaction) and ABAQUS systems. Using finite element calculations, it was possible to explain the phenomenon of roughness formation on the surface of a smooth steel sample. The changes in the structure of the smooth surface resulting from compression in the presence of oil are caused by the rotation and deformation of surface grains. The roughness of this structure is dependent on the viscosity of oil: the more viscous the liquid is, the rougher texture is formed.

The method of calculations of a thick plate on the two-parameter layered foundation by the finite element method is presented. The numerical model allows to add a few (number of) foundation layers. The expressions for the element stiffness matrices of the foundation are based on 18-node zero-thickness interface elements. For modelling of thick plates the 9-node Mindlin element of the Lagrange family is used. The formulation of the problem takes into account the shear deformation of the plate and unilateral contact conditions between plate and foundation. The tensionless character of the foundation is achieved by removing from the global stiffness matrix the appropriate part of foundation stiffness attached to the node being in the separation stage. The advantages of the proposed algorithm are illustrated by numerical examples.