Wyniki wyszukiwania - BazTech

1

The mechanical behaviour of dental implant with stress barrier

Merdji A., Aminallah L., Bachir Bouiadjra B., Serier B., Mootanah R., Ould Chikh E.B., Moslih A.M.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2011

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z. 99

36-37

EN

It has been well known that the success of dental implant is heavily dependent on initial stability and long-term osseo-integration due to optimal stress distribution in the surrounding bones. For this reason, the search of the rational solutions to reduce these stresses has become an important issue in this field. Alternatives to reduce the forces transmitted to implants have been studied, including variations in implant positioning, implant design, prosthesis shape, occlusal requirements, prosthetic components and prosthetic materials. Thus, a new concept of adding a bio-elastomer to the prosthetic components of implant system was interposed between the abutment and the framework crown in order to damp the occlusive shocks and to attenuate the stress concentrated at the implant/bone interface. The new implant system design was assessed by the three dimensional finite element techniques using ABAQUS program to study the effect of elastomer material under an occlusal load on the induced equivalent von Mises interface stresses. These stresses were compared with those provoked by the standardized implant. The von Mises stress distribution indicated that stress was maximal around the top of the implant with varying intensities in the different loading cases. The stress was highest in the cortical bone at the neck of implant and lowest in the cancellous bone. Overall, the novel implant provoked lower interface stresses only in the cortical bone due to the stress shielding effect of the elastomeric stress barrier.

2

The fretting fatigue of the bolted assemblies

Benhamena A., Aminallah L., Aid A., Benguediab M., Amrouche A., Benseddiq N.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2011

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z. 99

17-17

EN

One of the principal failures of bolting assemblies is the fretting. The combi- nation of vibration and service load can introduce the damage of fretting fatigue on the contact surfaces of the assembly which trend to evoke a nucleation of crack and then the structure fracture. Contact pressure or clamping force and displacement at the interface or relative slip are two important factors which control the fretting wear and the fretting fatigue. This paper describes the effect of clamping force (tightening torque) on the fretting fatigue behavior of bolted assemblies.

3

Numerical analysis of the effect of thermal residual stresses on the performances of bonded composite repairs in aircraft structures

Aminallah L., Benhamena A., Aid A., Merdji A., Bouiadjra B., Serier B., Benseddio N.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2011

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z. 99

13-13

EN

In this study the finite element method is used to analyse the effect of the thermal residual stresses resulting from adhesive curing on the performances of the bonded composite repair in aircraft structures. The stress-intensity factor at the crack tip is chosen as fracture criterion in order to estimate the repair performances. The obtained results show that the presence of the thermal residual stresses reduces considerably the repair performances and consequently decreases the fatigue life of cracked structures. The effects of the curing temperature, the adhesive properties and the adhesive thickness on the stress intensity factor (SIF) variation with thermal stresses are also analysed.