Procena integriteta zavarenih spojeva sa neprihvatljivim greškama
Integrity assessment of welded joints with unacceptable defects
2023
Аутори
Opačić, MirjanaОстала ауторства
Sedmak, AleksandarBakić, Gordana
Grbović, Aleksandar
Radaković, Zoran
Sedmak, Simon
Докторска теза (Објављена верзија)
Метаподаци
Приказ свих података о документуАпстракт
Tema ove doktorske disertacije je procena rizika cilindričnih posuda pod pritiskom sa prslinom za komprimovani vazduh primenom osnovnih principa mehanike loma i naprednih metoda ispitivanja bez razaranja (NMIBR), kao što su ultrazvuk faznog niza (Phassed Array Ulatrasound Testing - PAUT) i vreme preleta difrakije (Time of Flight defraction - ToFD). Primenom naprednih metoda ultrazvučnog ispitivanja sa većom verovatnoćom detekcije moguće je pronaći sve indikacija grešeka unutar zavarenog spoja. Detektovane indikacije je moguće precizno locirati i dimenzionisati te dobijene vrednosti iskoristiti kao pouzdane ulazne podatke za dalju analizu integriteta zavarenog spoja i procenu rizika.
Korišćeni su osnovni principi mehnike loma za izračunavanje faktora intenziteta naprezanja, KI, i dobijanje odnosa KI/KIc, prema minimalno izmerenim vrednostima žilavosti loma zavarenih spojeva, kao tipičnih zona u kojima se nalaze greške tipa prsline. Heterogenost zavarenih spojeva je uzeta u obzir, jer s...e minimalna žilavost loma nalazi najčešće u zoni pod uticajem toplote (ZUT), ili metalu šava.
Odnos Snet/Sc, gde je Snet neto napon u poprečnom preseku sa prslinom, a Sc kritični napon, je izračunat da bi se definisala radna tačka u dijagramu procene otkaza (FAD), kako bi se na taj način procenila verovatnoća otkaza. U kombinaciji sa procenjenom posledicom, ovo omogućava primenu matrice rizika, kao jednostavnog alata za procenu rizika. U ovoj doktorskoj disertaciji fokus je na ulozi NMIBR-a, jer je od najveće važnosti koristiti što precizniju i pouzdaniju metodu za otkrivanje indikacija grešaka u zavarenim spojevima.
U ovom radu korišćene su napredne ultrazvučne metode PAUT i TOFD za dobijanje precizne slike grešaka u posudama pod pritiskom za komprimovani vazduh u reverzibilnoj hidroelektrani Bajina Bašta (RHEBB), koje su prethodno otkrivene i ocenjene kao neprihvatljive konvencionalnim metodama ispitivanja bez razaranja (IBR). Pokazano je da je upotreba NMIBR, PAUT i TOFD od najveće važnosti za proces donošenja odluka na osnovu procene integiteta i rizika.
Na taj način je postignut osnovni cilj doktorske disertacije da se dokaze da primenom NMIBR u kombinaciji sa osnovnim principima mehanike lome dobija pouzdana procena integriteta zavarenog spoja sa neprihvatljivim greškama. Kombinacija proračuna faktora inteziteta naprezanja koristeći konzervativne principe mehanike loma i unosa polaznih parametara vrednosti indikacije grešaka dobijenih ispitivanjima NMIBR, omogućuju primenu na različitim slučajevima prcene integriteta zavarenih spojeva kako bi se izbegle nepotrebne i skupe popravke tamo gde je to moguće.
The subject of this doctoral dissertation is the risk assessment of cylindrical pressure vessels with a compressed air crack using the basic principles of fracture mechanics and advanced non-destructive testing methods (NMIBR), such as Phased Array Ultrasound Testing (PAUT) and time-of-flight defraction (Time of Flight defraction - TOFD). Using advanced ultrasonic testing methods with a higher probability of detection, it is possible to find all indications of faults within the welded joint. The detected indications can be precisely located and dimensioned, and the obtained values can be used as reliable input data for further analysis of the integrity of the welded joint and risk assessment.
The basic principles of fracture mechanics were used to calculate the stress intensity factor, KI, and obtain the ratio KI/KIc, according to the minimum measured values of the fracture toughness of welded joints, as typical zones where there are crack-type errors. The heterogeneity of welded join...ts is taken into account, because the minimum fracture toughness is most often found in the heat affected zone (HAZ), or weld metal.
The ratio Snet/Sc, where Snet is the net stress in the cross-section with the crack and Sc is the critical stress, is calculated to define the operating point in the failure assessment diagram (FAD), thereby estimating the probability of failure. Combined with the estimated consequence, this enables the application of the risk matrix, as a simple risk assessment tool. In this doctoral dissertation, the focus is on the role of NMIBR, because it is of the utmost importance to use the most accurate and reliable method for detecting indications of errors in welded joints.
In this work, advanced ultrasonic methods PAUT and TOFD were used to obtain a precise image of defects in compressed air pressure vessels in the Bajina Bašta Reversible Hydropower Plant (RHEBB), which were previously detected and assessed as unacceptable by conventional non-destructive testing (NDT) methods. It has been shown that the use of NMIBR, PAUT and TOFD is of utmost importance for the decision-making process based on integrity and risk assessment.
In this way, the main goal of the doctoral dissertation was achieved, to prove that by applying NMIBR in combination with the basic principles of fracture mechanics, a reliable assessment of the integrity of the welded joint with unacceptable errors is obtained. The combination of stress intensity factor calculation using conservative principles of fracture mechanics and input of initial parameters of fault indication values obtained from NMIBR tests, allow application to different cases of evaluating the integrity of welded joints in order to avoid unnecessary and expensive repairs where possible.
Кључне речи:
Integritet zavarenog spoja / mehanika loma / metoda konačnih elemenata / napredne ultrazvučne metode / Phased Array (PA) / time of flight defraction (TOFD) / neprihvatljive greške / ispitivanje bez razaranja / Weld integrity / fracture mechanics / finite element method / advanced ultrasonic methods / Phased Array (PA) / unacceptable defects / non-destructive testingИзвор:
Univerzitet u Beogradu, Mašinski fakultet, 2023, 1-99Колекције
Институција/група
Mašinski fakultetTY - THES AU - Opačić, Mirjana PY - 2023 UR - https://machinery.mas.bg.ac.rs/handle/123456789/7733 AB - Tema ove doktorske disertacije je procena rizika cilindričnih posuda pod pritiskom sa prslinom za komprimovani vazduh primenom osnovnih principa mehanike loma i naprednih metoda ispitivanja bez razaranja (NMIBR), kao što su ultrazvuk faznog niza (Phassed Array Ulatrasound Testing - PAUT) i vreme preleta difrakije (Time of Flight defraction - ToFD). Primenom naprednih metoda ultrazvučnog ispitivanja sa većom verovatnoćom detekcije moguće je pronaći sve indikacija grešeka unutar zavarenog spoja. Detektovane indikacije je moguće precizno locirati i dimenzionisati te dobijene vrednosti iskoristiti kao pouzdane ulazne podatke za dalju analizu integriteta zavarenog spoja i procenu rizika. Korišćeni su osnovni principi mehnike loma za izračunavanje faktora intenziteta naprezanja, KI, i dobijanje odnosa KI/KIc, prema minimalno izmerenim vrednostima žilavosti loma zavarenih spojeva, kao tipičnih zona u kojima se nalaze greške tipa prsline. Heterogenost zavarenih spojeva je uzeta u obzir, jer se minimalna žilavost loma nalazi najčešće u zoni pod uticajem toplote (ZUT), ili metalu šava. Odnos Snet/Sc, gde je Snet neto napon u poprečnom preseku sa prslinom, a Sc kritični napon, je izračunat da bi se definisala radna tačka u dijagramu procene otkaza (FAD), kako bi se na taj način procenila verovatnoća otkaza. U kombinaciji sa procenjenom posledicom, ovo omogućava primenu matrice rizika, kao jednostavnog alata za procenu rizika. U ovoj doktorskoj disertaciji fokus je na ulozi NMIBR-a, jer je od najveće važnosti koristiti što precizniju i pouzdaniju metodu za otkrivanje indikacija grešaka u zavarenim spojevima. U ovom radu korišćene su napredne ultrazvučne metode PAUT i TOFD za dobijanje precizne slike grešaka u posudama pod pritiskom za komprimovani vazduh u reverzibilnoj hidroelektrani Bajina Bašta (RHEBB), koje su prethodno otkrivene i ocenjene kao neprihvatljive konvencionalnim metodama ispitivanja bez razaranja (IBR). Pokazano je da je upotreba NMIBR, PAUT i TOFD od najveće važnosti za proces donošenja odluka na osnovu procene integiteta i rizika. Na taj način je postignut osnovni cilj doktorske disertacije da se dokaze da primenom NMIBR u kombinaciji sa osnovnim principima mehanike lome dobija pouzdana procena integriteta zavarenog spoja sa neprihvatljivim greškama. Kombinacija proračuna faktora inteziteta naprezanja koristeći konzervativne principe mehanike loma i unosa polaznih parametara vrednosti indikacije grešaka dobijenih ispitivanjima NMIBR, omogućuju primenu na različitim slučajevima prcene integriteta zavarenih spojeva kako bi se izbegle nepotrebne i skupe popravke tamo gde je to moguće. AB - The subject of this doctoral dissertation is the risk assessment of cylindrical pressure vessels with a compressed air crack using the basic principles of fracture mechanics and advanced non-destructive testing methods (NMIBR), such as Phased Array Ultrasound Testing (PAUT) and time-of-flight defraction (Time of Flight defraction - TOFD). Using advanced ultrasonic testing methods with a higher probability of detection, it is possible to find all indications of faults within the welded joint. The detected indications can be precisely located and dimensioned, and the obtained values can be used as reliable input data for further analysis of the integrity of the welded joint and risk assessment. The basic principles of fracture mechanics were used to calculate the stress intensity factor, KI, and obtain the ratio KI/KIc, according to the minimum measured values of the fracture toughness of welded joints, as typical zones where there are crack-type errors. The heterogeneity of welded joints is taken into account, because the minimum fracture toughness is most often found in the heat affected zone (HAZ), or weld metal. The ratio Snet/Sc, where Snet is the net stress in the cross-section with the crack and Sc is the critical stress, is calculated to define the operating point in the failure assessment diagram (FAD), thereby estimating the probability of failure. Combined with the estimated consequence, this enables the application of the risk matrix, as a simple risk assessment tool. In this doctoral dissertation, the focus is on the role of NMIBR, because it is of the utmost importance to use the most accurate and reliable method for detecting indications of errors in welded joints. In this work, advanced ultrasonic methods PAUT and TOFD were used to obtain a precise image of defects in compressed air pressure vessels in the Bajina Bašta Reversible Hydropower Plant (RHEBB), which were previously detected and assessed as unacceptable by conventional non-destructive testing (NDT) methods. It has been shown that the use of NMIBR, PAUT and TOFD is of utmost importance for the decision-making process based on integrity and risk assessment. In this way, the main goal of the doctoral dissertation was achieved, to prove that by applying NMIBR in combination with the basic principles of fracture mechanics, a reliable assessment of the integrity of the welded joint with unacceptable errors is obtained. The combination of stress intensity factor calculation using conservative principles of fracture mechanics and input of initial parameters of fault indication values obtained from NMIBR tests, allow application to different cases of evaluating the integrity of welded joints in order to avoid unnecessary and expensive repairs where possible. T2 - Univerzitet u Beogradu, Mašinski fakultet T1 - Procena integriteta zavarenih spojeva sa neprihvatljivim greškama T1 - Integrity assessment of welded joints with unacceptable defects EP - 99 SP - 1 UR - https://hdl.handle.net/21.15107/rcub_machinery_7733 ER -
@phdthesis{ author = "Opačić, Mirjana", year = "2023", abstract = "Tema ove doktorske disertacije je procena rizika cilindričnih posuda pod pritiskom sa prslinom za komprimovani vazduh primenom osnovnih principa mehanike loma i naprednih metoda ispitivanja bez razaranja (NMIBR), kao što su ultrazvuk faznog niza (Phassed Array Ulatrasound Testing - PAUT) i vreme preleta difrakije (Time of Flight defraction - ToFD). Primenom naprednih metoda ultrazvučnog ispitivanja sa većom verovatnoćom detekcije moguće je pronaći sve indikacija grešeka unutar zavarenog spoja. Detektovane indikacije je moguće precizno locirati i dimenzionisati te dobijene vrednosti iskoristiti kao pouzdane ulazne podatke za dalju analizu integriteta zavarenog spoja i procenu rizika. Korišćeni su osnovni principi mehnike loma za izračunavanje faktora intenziteta naprezanja, KI, i dobijanje odnosa KI/KIc, prema minimalno izmerenim vrednostima žilavosti loma zavarenih spojeva, kao tipičnih zona u kojima se nalaze greške tipa prsline. Heterogenost zavarenih spojeva je uzeta u obzir, jer se minimalna žilavost loma nalazi najčešće u zoni pod uticajem toplote (ZUT), ili metalu šava. Odnos Snet/Sc, gde je Snet neto napon u poprečnom preseku sa prslinom, a Sc kritični napon, je izračunat da bi se definisala radna tačka u dijagramu procene otkaza (FAD), kako bi se na taj način procenila verovatnoća otkaza. U kombinaciji sa procenjenom posledicom, ovo omogućava primenu matrice rizika, kao jednostavnog alata za procenu rizika. U ovoj doktorskoj disertaciji fokus je na ulozi NMIBR-a, jer je od najveće važnosti koristiti što precizniju i pouzdaniju metodu za otkrivanje indikacija grešaka u zavarenim spojevima. U ovom radu korišćene su napredne ultrazvučne metode PAUT i TOFD za dobijanje precizne slike grešaka u posudama pod pritiskom za komprimovani vazduh u reverzibilnoj hidroelektrani Bajina Bašta (RHEBB), koje su prethodno otkrivene i ocenjene kao neprihvatljive konvencionalnim metodama ispitivanja bez razaranja (IBR). Pokazano je da je upotreba NMIBR, PAUT i TOFD od najveće važnosti za proces donošenja odluka na osnovu procene integiteta i rizika. Na taj način je postignut osnovni cilj doktorske disertacije da se dokaze da primenom NMIBR u kombinaciji sa osnovnim principima mehanike lome dobija pouzdana procena integriteta zavarenog spoja sa neprihvatljivim greškama. Kombinacija proračuna faktora inteziteta naprezanja koristeći konzervativne principe mehanike loma i unosa polaznih parametara vrednosti indikacije grešaka dobijenih ispitivanjima NMIBR, omogućuju primenu na različitim slučajevima prcene integriteta zavarenih spojeva kako bi se izbegle nepotrebne i skupe popravke tamo gde je to moguće., The subject of this doctoral dissertation is the risk assessment of cylindrical pressure vessels with a compressed air crack using the basic principles of fracture mechanics and advanced non-destructive testing methods (NMIBR), such as Phased Array Ultrasound Testing (PAUT) and time-of-flight defraction (Time of Flight defraction - TOFD). Using advanced ultrasonic testing methods with a higher probability of detection, it is possible to find all indications of faults within the welded joint. The detected indications can be precisely located and dimensioned, and the obtained values can be used as reliable input data for further analysis of the integrity of the welded joint and risk assessment. The basic principles of fracture mechanics were used to calculate the stress intensity factor, KI, and obtain the ratio KI/KIc, according to the minimum measured values of the fracture toughness of welded joints, as typical zones where there are crack-type errors. The heterogeneity of welded joints is taken into account, because the minimum fracture toughness is most often found in the heat affected zone (HAZ), or weld metal. The ratio Snet/Sc, where Snet is the net stress in the cross-section with the crack and Sc is the critical stress, is calculated to define the operating point in the failure assessment diagram (FAD), thereby estimating the probability of failure. Combined with the estimated consequence, this enables the application of the risk matrix, as a simple risk assessment tool. In this doctoral dissertation, the focus is on the role of NMIBR, because it is of the utmost importance to use the most accurate and reliable method for detecting indications of errors in welded joints. In this work, advanced ultrasonic methods PAUT and TOFD were used to obtain a precise image of defects in compressed air pressure vessels in the Bajina Bašta Reversible Hydropower Plant (RHEBB), which were previously detected and assessed as unacceptable by conventional non-destructive testing (NDT) methods. It has been shown that the use of NMIBR, PAUT and TOFD is of utmost importance for the decision-making process based on integrity and risk assessment. In this way, the main goal of the doctoral dissertation was achieved, to prove that by applying NMIBR in combination with the basic principles of fracture mechanics, a reliable assessment of the integrity of the welded joint with unacceptable errors is obtained. The combination of stress intensity factor calculation using conservative principles of fracture mechanics and input of initial parameters of fault indication values obtained from NMIBR tests, allow application to different cases of evaluating the integrity of welded joints in order to avoid unnecessary and expensive repairs where possible.", journal = "Univerzitet u Beogradu, Mašinski fakultet", title = "Procena integriteta zavarenih spojeva sa neprihvatljivim greškama, Integrity assessment of welded joints with unacceptable defects", pages = "99-1", url = "https://hdl.handle.net/21.15107/rcub_machinery_7733" }
Opačić, M.. (2023). Procena integriteta zavarenih spojeva sa neprihvatljivim greškama. in Univerzitet u Beogradu, Mašinski fakultet, 1-99. https://hdl.handle.net/21.15107/rcub_machinery_7733
Opačić M. Procena integriteta zavarenih spojeva sa neprihvatljivim greškama. in Univerzitet u Beogradu, Mašinski fakultet. 2023;:1-99. https://hdl.handle.net/21.15107/rcub_machinery_7733 .
Opačić, Mirjana, "Procena integriteta zavarenih spojeva sa neprihvatljivim greškama" in Univerzitet u Beogradu, Mašinski fakultet (2023):1-99, https://hdl.handle.net/21.15107/rcub_machinery_7733 .