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We have developed a curved finite element for a cylindrical thick shell based on the thick shell equations established in 1999 by Nzengwa and Tagne (N-T). The displacement field of the shell is interpolated from nodal displacements only and strains assumption. Numerical results on a cylindrical thin shell are compared with those of other well-known benchmarks with satisfaction. Convergence is rapidly obtained with very few elements. A scaling was processed on the cylindrical thin shell by increasing the ratioχ=h/2R(half the thickness over the smallest radius in absolute value) and comparing results with those obtained with the classical Kirchhoff-Love thin shell theory; it appears that results diverge at2χ=1/10=0.316because of the significant energy contribution of the change of the third fundamental form found in N-T model. This limit value of the thickness ratio which characterizes the limit between thin and thick cylindrical shells differs from the ratio 0.4 proposed by Leissa and 0.5 proposed by Narita and Leissa.

Experimental studies have been carried out to establish the possibility of using vibratory machining technology through shock-wave transmission for oxide coating preparation on aluminum-alloyed machine components and also to discuss the technological possibilities of applying vibration mechanochemical solid lubricant coatings based on MoS 2 to improve the surface quality and performance properties of machine component parts. The coating characteristics are determined by measuring and comparing certain tribological properties of the samples before processing, after normal coating, and after vibratory coating process. A deeper study with a scanning microscope was made by comparing result of normal and vibratory coating. The vibratory coating shows a reduction of grain sizes, a regular orientation of the grain, and a dense grain structure leading to the formation of a thin layer covered by a film orientated parallel to the surface of friction giving an imparted surface finish. The reduction of microroughness is also accompanied with good performances in terms of increasing in wear resistance and decreasing in coefficient of friction. This reflects the presence of complex influence of mechanical and chemical components in the formation of coating on superficial layers during lower shock-wave vibration giving at the end structured ameliorated state of surface that leads to an increase in the part lifespan and equally shows technological opportunities that can be used to improve surface quality and performance properties of machine component parts.

The target in this survey is to investigate deformations of laminates shells (DLS), due to asymmetric and axisymmetric loads, including several other loadings using N-T shell equations. We point out here, the contribution of the metric change in thickness for the analysis of static and linear behavior of laminated composite shells. To achieve this objective, we’ve applied N-T’s shells equations on the same monolayer laminate composite shell and derive the law of MBLS. The macrostructure is analyzed under static loads and implemented using low order curved shell finite elements with shifted Lagrange (CSFE-sh). We tested this element on benchmarks found within the literature. The analysis of cylindrical and spherical shells subjected to uniform sinusoidal pressures and asymmetric pressures reveals excellent accuracy compared to others. The results found without any correction factor were compared with those obtained by the analytical method and other finite element models.