Advanced Materials

Damage assessment and retrofit study for the Luxor Memnon Colossi

by Sara Casciati

Casciati S. and Osman A. M. (2005). “Damage assessment and retrofit study for the Luxor Memnon Colossi”. Structural Control & Health Monitoring, 12(2), 139-156. ISSN: 1545-2255.

DATE AND PLACE OF PUBBLICATION: April-June 2005; John Wiley & Sons, Ltd., Chichester PO19 8SQ, W Sussex, England.

ABSTRACT. The structural behaviour of large, monolithic, ancient monuments consisting of heavy stone blocks connected... more ABSTRACT. The structural behaviour of large, monolithic, ancient monuments consisting of heavy stone blocks connected one to the other by the gravity load alone, without the use of mortar, is investigated. The Memnon Colossi, which were built fourteen centuries before Christ at Luxor in Egypt, are the case study for this construction technique. This paper summarizes the results of studies carried out on this structure within the CHIME (Conservation of Historical Monuments in the Mediterranean Area) project, funded by the European Commission.
The modal frequencies of the two statues were identified experimentally from ambient vibration measurements. Analytical models using the finite element method were also elaborated to compare the numerical results with the experimental ones, and to perform dynamic analyses. The results indicated that the distributed cracks characterizing the current state of the structure, play a significant role in the static and dynamic response of the monument. In view of the monuments’ rehabilitation, an innovative technology, based on fastening the cracked blocks by pre-tensioned wires of shape memory alloy, is proposed and numerically simulated.

KEY WORDS: monument; modal identification; damage assessment; retrofit; shape memory alloy

Nonlinear aspects of energy dissipation in wood-panel joints

by Sara Casciati

Casciati S. (2007). “Nonlinear aspects of energy dissipation in wood-panel joints”. Earthquake Engineering and Engineering Vibration, 6(3), 259-268. ISSN: 1671-3664.

DATA E LUOGO DI PUBBLICAZIONE: September 2007; Springer, New York, NY 10013, USA.

ABSTRACT: The joints connecting vertical and horizontal elements are the “weak link” in structural systems assembled... more ABSTRACT: The joints connecting vertical and horizontal elements are the “weak link” in structural systems assembled from wood panels. If they are too weak, local failures may occur, resulting in performance that is significantly below expectations. If they are too resistant, the joints may be unable to dissipate energy during vibrations, thus possibly initiating a fast progressive failure. This paper re-processes and re-elaborates the results of shaking table tests previously carried out by the author and other co-workers. The goal is to assess the feasibility of a joint which is able to dissipate energy during vibration, without degrading the connection performance.

KEYWORDS: dynamic excitation - energy dissipation - wood panels joint - monitoring system - shaking table tests

Fatigue characterization of a Cu-based shape memory alloy

by Sara Casciati

Casciati F., Casciati S., and Faravelli L. (2007). “Fatigue characterization of a Cu-based shape memory alloy”. Proceedings of the Estonian Academy of Sciences – Physics Mathematics, 56(2), 207-217. ISSN: 1406-0086.

DATE AND PLACE OF PUBBLICATION: June 2007; Estonian Academy Publishers, Tallinn 10143, Estonia.

ABSTRACT: Applications of a Cu-based shape memory alloy in monuments retrofitting were conceived, designed, and... more ABSTRACT: Applications of a Cu-based shape memory alloy in monuments retrofitting were conceived, designed, and tested. The polycrystalline nature of the material requires a preliminary discussion in order to allow the extension of properties which are well known for monocrystalline specimens. Furthermore, one of the main drawbacks of the investigated alloy is its brittleness. Therefore, fatigue tests were carried out and the results of those conducted under cycles of torsion loading–unloading are reported. In particular, the identification of the response range, which is most suitable for structural engineering applications, is pursued.

KEYWORDS: compression tests, fatigue tests, shape memory alloy, tension tests, torsion tests, thermal treatment.

Application of Langmuir-Blodgett technique to preparation of advanced materials

by Shanming Ke

Published in "Mater. Rev.", 2005

Synergistic role of Lewis and Brönsted acidities in Friedel–Crafts alkylation of resorcinol over gallium-zeolite beta

by Hadi Nur

published in 'Catalysis Communications', 2011

The role of Lewis and Brönsted acidities in alkylation of resorcinol is demonstrated through the galliumzeolite beta... more The role of Lewis and Brönsted acidities in alkylation of resorcinol is demonstrated through the galliumzeolite beta by varying the amount of Lewis and Brönsted acid sites. The synergism of Lewis and Brönsted acid sites takes place heterogeneously in Friedel–Crafts alkylation of resorcinol with methyl tert-butyl ether to produce 4-tert-butyl resorcinol and 4,6-di-tert-butyl resorcinol as the major and minor products, respectively.

Fatigue Behaviour of Low Temperature Carburised AISI 316L Austenitic Stainless Steel

by Giangiacomo Minak

Fatigue properties of friction stir welded particulate reinforced aluminium matrix composites

by Giangiacomo Minak

G. Minak, L. Ceschini, I. Boromei, M. Ponte, International Journal of Fatigue 32 (2010) 218–226

Few papers have discussed the friction stir welding (FSW) of particulate reinforced aluminium matrix composites and... more Few papers have discussed the friction stir welding (FSW) of particulate reinforced aluminium matrix composites and most of them focused on the set-up of the welding process parameters and their effect on microstructure, hardness and tensile behaviour. The aim of this study was to investigate the fatigue resistance of FSW joints on an as-cast particulate reinforced aluminium based composite (AA6061/ 22vol.%/Al2O3p). The welding process was performed using different process parameters, also investigating their effect on joint microstructure. The mechanical properties of the FSW composites were compared with those of the base material and the results were correlated to the microstructural modifications induced by the FSW process on the aluminium alloy matrix and the ceramic reinforcement. FSW reduced the size of both particle reinforcement and aluminium grains, and also led to a significant increase in interparticle matrix microhardness, for all process parameters. The FSW specimens belonging to a different set of parameters, tested without any post-weld heat treatment, exhibited a very high joint efficiency (ranging from 90% to 99%) with respect to the ultimate tensile strength of the base material. The stress controlled fatigue test showed a high spread both for the base and FSW composites. Statistical analysis disclosed that all FSW specimens belonging to different process parameters showed apparently slightly worse fatigue behaviour than that of the base composite. Statistical processing applied to the different welding parameters revealed that all the welded specimens belonged to the same population. Therefore it can be concluded that the parameters used produced joints with similar microstructure and comparable fatigue behaviour. The slight difference in the fatigue behaviour of the FSW specimens whose process parameters differed form those of the unwelded composite was explained by the different microstructural homogeneity in the transition from the base to the FSW zone.