Tensile and compression tests are a part of the qualification process for composite parts in airc... more Tensile and compression tests are a part of the qualification process for composite parts in aircraft structures. With each new material, a new set of tests is required. To reduce costs, it is advantageous to develop analysis tools for the prediction of damages and failure in such tests, so that the amount of testing can be reduced and predictions about material behavior can be made early in the design process. In this paper, an experimental and numerical study is presented on the tensile and compression strength of composite material developed by Alenia Aeronautica for aerospace applications and produced by means of the resin film infusion (RFI) and stitching process. Tensile and compression tests have been performed on specimens with three different lay-ups: 33/33/33, 40/40/20 and 100/0/0. They refer to the percentage of oriented fibres for each layer along three directions (0°/±45°/90°). The data observed are being used to develop a method for predicting the tensile and compression strength, and the numerical results are compared with the experimental ones.
Since May 2007, many manufactories of beverage’s cans have replaced the “standard can” with a new... more Since May 2007, many manufactories of beverage’s cans have replaced the “standard can” with a new one, named “sleek can”. The traditional can now changes its shape, becoming taller and slimmer, but containing the same volume of beverage (33 cl). The total volume of a sleek can results smaller than the total volume of a standard can. A study on mechanical behavior of cans subjected to controlled thermal loads was carried out. The aim of the present work is to experimentally study the strains field on both types of can and different types of commercial beverages, and to identify the most dangerous condition. Experimental tests were executed realizing either a thermal shock or a gradual increase of temperature. A finite elements model was implemented. Strains obtained from experimental tests were compared with the numerical ones and the stress field of the can was evaluated. The soft drinks considered were sprite and coke. They are very common soft drinks, widely appreciated by young consumers. So it becomes fundamental that the cans are not only functional but also safe. In fact, drinks containing a considerable quantity of carbon dioxide (5.4 g/l of CO2 for coke and 7.2 g/l CO2 for sprite), can be considered a sort of pressure tanks because shaking the beverage or increasing the temperature, produces a growth of the gas pressure on the can walls. An experiment was simulated: it was supposed to leave a can in a car during a sunny day. The temperature reached was higher than 70 °C (in south of Italy in September). A preliminary test was executed and it was observed that heating with hot domestic water, the can end was violently removed from the can body, hitting the operator. For this reason an-in-depth study was conducted.
The effect, on the residual stress measurement accuracy, of the drilling speed of the end-mill du... more The effect, on the residual stress measurement accuracy, of the drilling speed of the end-mill during the hole-drilling measurements was evaluated in Ti6Al4V. In spite of the well-known consideration that the highest achievable speed should be used during hole drilling, very few experimental works exist analyzing the effects of using lower velocities. Hole-drilling experiments were performed in this study by measuring the released strain by electronic speckle pattern interferometry. A known stress state was generated by loading the sample in a four point bending frame up to 50% of the yield strength. Drilling speed ranging in 5000 ÷ 50000 rpm was investigated by using an electronically controlled mill. The expected stress field, evaluated by a numerical model in ANSYS®, was compared with the measured one at different drilling speeds.
Sommario Il processo di Selective Laser Melting (SLM) è una delle tecnologie più interessanti tra... more Sommario Il processo di Selective Laser Melting (SLM) è una delle tecnologie più interessanti tra i processi di prototipazione rapida grazie alla possibilità di realizzare complessi manufatti 3D in metallo, con densità elevata e con proprietà meccaniche comparabili a quelle dei componenti prodotti con tecnologie convenzionali. Questo obiettivo può essere raggiunto utilizzando laser in grado di garantire elevati valori della densità di energia con basse velocità di scansione. Queste condizioni, unitamente ad una appropriata strategia di scansione, permettono la completa fusione delle particelle di polvere. Il meccanismo di fusione/solidificazione genera tensioni termiche residue altamente variabili nei pezzi prodotti con il processo SLM. Questo lavoro si propone di studiare la distribuzione di tensioni residue generate in componenti prodotti in acciaio 18 Ni Marage 300 al variare della strategia di scansione e dei principali parametri di processo. La misura delle tensioni residue vie...
Scopo del presente lavoro è individuare le prestazioni meccaniche di un nuovo materiale composito... more Scopo del presente lavoro è individuare le prestazioni meccaniche di un nuovo materiale composito costituito da fibre lunghe a modulo standard e resina epossidica termoindurente tenacizzata. Tale composito è tessuto con vari layer, ciascuno contenente fasci di fibre paralleli ed affiancati tra loro secondo l’orientazione propria del layer stesso, sovrapposti e tenuti uniti mediante processo di cucitura delle preforme, successivamente impregnate con resina a caldo e sotto pressione (RFI). Al fine di simulare le condizioni di esercizio del materiale è stata condotta una campagna di prove meccaniche a caldo e ad elevata umidità relativa (71°C) per simulare un invecchiamento accelerato del materiale e le condizioni di lavoro delle parti di composito vicine ai motori, a freddo (-54°C) per simulare le condizioni di lavoro in volo, e a temperatura ambiente (23°C). Sono state eseguite diverse tipologie di prova: trazione, trazione open hole e filled hole, compressione, compressione open hole e filled hole, taglio, flessione, bearing con 1 e 2 fastners. Il confronto dei risultati tra le diverse temperature ha evidenziato gli effetti benefici del raffreddamento del materiale a -54°C, rispetto ai test condotti alle altre due temperature di prova ed ha inoltre mostrato che le caratteristiche di resistenza, contrariamente alle aspettative, non hanno risentito dell’aumentare della temperatura per via del comportamento stabile delle fibre di carbonio. L’analisi delle differenti tipologie di prova ha inoltre messo in evidenza che una maggiore percentuale di fibre lungo la direzione di prova conferisce al materiale migliori caratteristiche di resistenza.
Tensile and compression tests are a part of the qualification process for composite parts in airc... more Tensile and compression tests are a part of the qualification process for composite parts in aircraft structures. With each new material, a new set of tests is required. To reduce costs, it is advantageous to develop analysis tools for the prediction of damages and failure in such tests, so that the amount of testing can be reduced and predictions about material behavior can be made early in the design process. In this paper, an experimental and numerical study is presented on the tensile and compression strength of composite material developed by Alenia Aeronautica for aerospace applications and produced by means of the resin film infusion (RFI) and stitching process. Tensile and compression tests have been performed on specimens with three different lay-ups: 33/33/33, 40/40/20 and 100/0/0. They refer to the percentage of oriented fibres for each layer along three directions (0°/±45°/90°). The data observed are being used to develop a method for predicting the tensile and compression strength, and the numerical results are compared with the experimental ones.
Since May 2007, many manufactories of beverage’s cans have replaced the “standard can” with a new... more Since May 2007, many manufactories of beverage’s cans have replaced the “standard can” with a new one, named “sleek can”. The traditional can now changes its shape, becoming taller and slimmer, but containing the same volume of beverage (33 cl). The total volume of a sleek can results smaller than the total volume of a standard can. A study on mechanical behavior of cans subjected to controlled thermal loads was carried out. The aim of the present work is to experimentally study the strains field on both types of can and different types of commercial beverages, and to identify the most dangerous condition. Experimental tests were executed realizing either a thermal shock or a gradual increase of temperature. A finite elements model was implemented. Strains obtained from experimental tests were compared with the numerical ones and the stress field of the can was evaluated. The soft drinks considered were sprite and coke. They are very common soft drinks, widely appreciated by young consumers. So it becomes fundamental that the cans are not only functional but also safe. In fact, drinks containing a considerable quantity of carbon dioxide (5.4 g/l of CO2 for coke and 7.2 g/l CO2 for sprite), can be considered a sort of pressure tanks because shaking the beverage or increasing the temperature, produces a growth of the gas pressure on the can walls. An experiment was simulated: it was supposed to leave a can in a car during a sunny day. The temperature reached was higher than 70 °C (in south of Italy in September). A preliminary test was executed and it was observed that heating with hot domestic water, the can end was violently removed from the can body, hitting the operator. For this reason an-in-depth study was conducted.
The effect, on the residual stress measurement accuracy, of the drilling speed of the end-mill du... more The effect, on the residual stress measurement accuracy, of the drilling speed of the end-mill during the hole-drilling measurements was evaluated in Ti6Al4V. In spite of the well-known consideration that the highest achievable speed should be used during hole drilling, very few experimental works exist analyzing the effects of using lower velocities. Hole-drilling experiments were performed in this study by measuring the released strain by electronic speckle pattern interferometry. A known stress state was generated by loading the sample in a four point bending frame up to 50% of the yield strength. Drilling speed ranging in 5000 ÷ 50000 rpm was investigated by using an electronically controlled mill. The expected stress field, evaluated by a numerical model in ANSYS®, was compared with the measured one at different drilling speeds.
Sommario Il processo di Selective Laser Melting (SLM) è una delle tecnologie più interessanti tra... more Sommario Il processo di Selective Laser Melting (SLM) è una delle tecnologie più interessanti tra i processi di prototipazione rapida grazie alla possibilità di realizzare complessi manufatti 3D in metallo, con densità elevata e con proprietà meccaniche comparabili a quelle dei componenti prodotti con tecnologie convenzionali. Questo obiettivo può essere raggiunto utilizzando laser in grado di garantire elevati valori della densità di energia con basse velocità di scansione. Queste condizioni, unitamente ad una appropriata strategia di scansione, permettono la completa fusione delle particelle di polvere. Il meccanismo di fusione/solidificazione genera tensioni termiche residue altamente variabili nei pezzi prodotti con il processo SLM. Questo lavoro si propone di studiare la distribuzione di tensioni residue generate in componenti prodotti in acciaio 18 Ni Marage 300 al variare della strategia di scansione e dei principali parametri di processo. La misura delle tensioni residue vie...
Scopo del presente lavoro è individuare le prestazioni meccaniche di un nuovo materiale composito... more Scopo del presente lavoro è individuare le prestazioni meccaniche di un nuovo materiale composito costituito da fibre lunghe a modulo standard e resina epossidica termoindurente tenacizzata. Tale composito è tessuto con vari layer, ciascuno contenente fasci di fibre paralleli ed affiancati tra loro secondo l’orientazione propria del layer stesso, sovrapposti e tenuti uniti mediante processo di cucitura delle preforme, successivamente impregnate con resina a caldo e sotto pressione (RFI). Al fine di simulare le condizioni di esercizio del materiale è stata condotta una campagna di prove meccaniche a caldo e ad elevata umidità relativa (71°C) per simulare un invecchiamento accelerato del materiale e le condizioni di lavoro delle parti di composito vicine ai motori, a freddo (-54°C) per simulare le condizioni di lavoro in volo, e a temperatura ambiente (23°C). Sono state eseguite diverse tipologie di prova: trazione, trazione open hole e filled hole, compressione, compressione open hole e filled hole, taglio, flessione, bearing con 1 e 2 fastners. Il confronto dei risultati tra le diverse temperature ha evidenziato gli effetti benefici del raffreddamento del materiale a -54°C, rispetto ai test condotti alle altre due temperature di prova ed ha inoltre mostrato che le caratteristiche di resistenza, contrariamente alle aspettative, non hanno risentito dell’aumentare della temperatura per via del comportamento stabile delle fibre di carbonio. L’analisi delle differenti tipologie di prova ha inoltre messo in evidenza che una maggiore percentuale di fibre lungo la direzione di prova conferisce al materiale migliori caratteristiche di resistenza.
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Papers by F. Tursi
traditional can now changes its shape, becoming taller and slimmer, but containing the same volume of beverage (33 cl). The total volume
of a sleek can results smaller than the total volume of a standard can. A study on mechanical behavior of cans subjected to controlled
thermal loads was carried out. The aim of the present work is to experimentally study the strains field on both types of can and different
types of commercial beverages, and to identify the most dangerous condition. Experimental tests were executed realizing either a thermal
shock or a gradual increase of temperature. A finite elements model was implemented. Strains obtained from experimental tests were
compared with the numerical ones and the stress field of the can was evaluated. The soft drinks considered were sprite and coke. They
are very common soft drinks, widely appreciated by young consumers. So it becomes fundamental that the cans are not only functional but
also safe. In fact, drinks containing a considerable quantity of carbon dioxide (5.4 g/l of CO2 for coke and 7.2 g/l CO2 for sprite), can be
considered a sort of pressure tanks because shaking the beverage or increasing the temperature, produces a growth of the gas pressure
on the can walls. An experiment was simulated: it was supposed to leave a can in a car during a sunny day. The temperature reached was
higher than 70 °C (in south of Italy in September). A preliminary test was executed and it was observed that heating with hot domestic
water, the can end was violently removed from the can body, hitting the operator. For this reason an-in-depth study was conducted.
measurements was evaluated in Ti6Al4V. In spite of the well-known consideration that the highest achievable speed should
be used during hole drilling, very few experimental works exist analyzing the effects of using lower velocities. Hole-drilling
experiments were performed in this study by measuring the released strain by electronic speckle pattern interferometry. A
known stress state was generated by loading the sample in a four point bending frame up to 50% of the yield strength.
Drilling speed ranging in 5000 ÷ 50000 rpm was investigated by using an electronically controlled mill. The expected stress
field, evaluated by a numerical model in ANSYS®, was compared with the measured one at different drilling speeds.
traditional can now changes its shape, becoming taller and slimmer, but containing the same volume of beverage (33 cl). The total volume
of a sleek can results smaller than the total volume of a standard can. A study on mechanical behavior of cans subjected to controlled
thermal loads was carried out. The aim of the present work is to experimentally study the strains field on both types of can and different
types of commercial beverages, and to identify the most dangerous condition. Experimental tests were executed realizing either a thermal
shock or a gradual increase of temperature. A finite elements model was implemented. Strains obtained from experimental tests were
compared with the numerical ones and the stress field of the can was evaluated. The soft drinks considered were sprite and coke. They
are very common soft drinks, widely appreciated by young consumers. So it becomes fundamental that the cans are not only functional but
also safe. In fact, drinks containing a considerable quantity of carbon dioxide (5.4 g/l of CO2 for coke and 7.2 g/l CO2 for sprite), can be
considered a sort of pressure tanks because shaking the beverage or increasing the temperature, produces a growth of the gas pressure
on the can walls. An experiment was simulated: it was supposed to leave a can in a car during a sunny day. The temperature reached was
higher than 70 °C (in south of Italy in September). A preliminary test was executed and it was observed that heating with hot domestic
water, the can end was violently removed from the can body, hitting the operator. For this reason an-in-depth study was conducted.
measurements was evaluated in Ti6Al4V. In spite of the well-known consideration that the highest achievable speed should
be used during hole drilling, very few experimental works exist analyzing the effects of using lower velocities. Hole-drilling
experiments were performed in this study by measuring the released strain by electronic speckle pattern interferometry. A
known stress state was generated by loading the sample in a four point bending frame up to 50% of the yield strength.
Drilling speed ranging in 5000 ÷ 50000 rpm was investigated by using an electronically controlled mill. The expected stress
field, evaluated by a numerical model in ANSYS®, was compared with the measured one at different drilling speeds.