Under seismic excitation, a pile undergoes stresses stemming from both the vibration of the surrounding soil (kinematic interaction) and that of the superstructure (inertial interaction). The relative contributions of kinematic and inertial interaction on the magnitude of seismic forces induced in pile foundations are investigated by means of nonlinear two-dimensional (2D) finite element (FE) analyses. The interaction between the pile and the surrounding soil in three-dimensional (3D) type was idealized in the 2D analysis using soil–pile interaction springs with hysteretic nonlinear load displacement relationships. Parametric analyses are carried out, focusing on normalized seismic forces in the piles as affected by typical characteristics of structures and piles as well as ground nonlinearity. The results of the study provide a new interpretation of the interplay between pile kinematic and inertial seismic forces. The numerical results showed that for relatively short/stiff piles or where structure’s natural frequency is lower than that of the ground, the kinematic interaction can be the prime contributor to the seismic forces in the pile provided that the excitation frequency is not close to the natural frequency of the coupled soil–pile–structure system, fSSI. In a frequency band approaching fSSI, the inertial interaction generally prevails imposing large bending moments at or near the pile head. The results showed also that maximum kinematic seismic force does not always occur at the fundamental frequency of the deposit. For certain relative soil–pile stiffness and excitation amplitudes, the largest peak of the kinematic seismic forces in piles can be occurring at the second mode.

Abstract Brass and brass alloys are widely employed industrial materials because of their excellent characteristics such as high corrosion resistance, non-magnetism, and good machinability. Surface quality plays a very important role in the performance of milled products, as good surface quality can significantly improve fatigue strength, corrosion resistance, or creep life. Surface roughness (Ra) is one of the most important factors for evaluating surface quality during the finishing process. The quality of surface affects the functional characteristics of the workpiece, including fatigue, corrosion, fracture resistance, and surface friction. Furthermore, surface roughness is among the most critical constraints in cutting parameter selection in manufacturing process planning. In this paper, the adaptive neuro-fuzzy inference system (ANFIS) was used to predict the surface roughness in computer numerical

The dynamic response of a preloaded bolted joint is investigated when subjected to harmonic excitation. The equations of motion of the joint are derived on the basis of a realistic linear mathematical model, by using simple spring-mass system analysis. Solutions for the joint response are obtained in the frequency domain in terms of the force and motion transmissibility ratios between joint plates. Although the main emphasis of this study is focused on the dynamic response of preloaded bolted joint as a criterion of design, the