Structural Health Monitoring of welded steel joints Graduation Project

مشروع تخرج بعنوان
Structural Health Monitoring of welded steel joints
Graduation Project
By:
Osama Nabil said
El-sayed Adelmeagyed Elsayed
Mohammed Nabil Abdelazim
Mahmoud Ahmed Salah
Yasser El-sayed Moftah
Supervised by:
Prof . Dr. Ahmed Refaat El-sissy
Chapter 1 Introduction to Structural Health Monitoring
Chapter 2 Experimental
Chapter 3 Results and Discussion
Chapter 4 Conclusions
Chapter 5 References
Abstract:
Structural Health Monitoring (SHM) aims to give a diagnosis of the state of structure of the material at every moment during the life of structure to remain it in specified domain in the design
In the present project, SHM welded steel pipes was used to diagnosis their state via vibration based damage detection techniques .these techniques are based on the principle that damage alters the dynamic properties of the structure such as mass, stiffness and damping .
It is therefore feasible to utilize the measured dynamic quantities such as Frequency Response Functions (FRFs) and modal parameters from structural vibration to detect damage.
Steel pipes made from carbon steel (ASTM A 106 grade B) were used in the present project. This type of steel is highly recommended for high pressure as well as high temperature applications such as pipe lines in boilers and oil
Two most commonly used welding techniques were used, namely: shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW). An artificial crack with depth of 2 mm, and width of 1mm were made in the welded region.
Static tests were performed to assure the quality of welded joints .these tests include: three point bending test (3PB), face bending, tensile testing, and buckling test. All the tests were made in accordance with the ASTM specification. In addition to the destructive tests, nondestructive tests were performed, there include: x- ray and liquid penetration inspection methods.
Dynamic tests were performed via an impact on a pipe, where three uniaxial accelerometers were kept at a certain location as a reference, and the pipe was impacted at 24 points. The data were acquired through FFT pulse analyzer, set on linear averaging mode, with a maximum frequency of analysis of 3.2 KHZ.
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” متابعة السلامه الإنشائية لمواسير الصلب الملحومه”
مواسير الصلب الملحومة لها العديد من التطبيقات الهندسية في نقل الغاز والبترول وكذا غلايات الطاقة.
ومن المعروف أن الوصلات الملحومه تمثل مرجعين للانهيارات نظراً لاحتوائها علي العديد من العيوب إضافة إلي الأجهارات المتبقية والتي لا يظهر تأثيرها إلا بعد مرور فترة من الزمن. لذا يهدف المشروع إلي استخدام اسلوب متابعة السلامه الانشائية لمواسير الصلب الملحومه بطريقتين (القوس الكهربي المحجب ولحام التنجستن) وهما الأكثر شيوعاً في هذا المجال .. ويعتمد أسلوب المتابعة علي تحديد ما يعرف بالبصمه عند بدء الاستخدام للوصله حيث يتم قياس الاخماد والتردد الطبيعي للمواسير ومن ثم قياس التغيرفي تلك القيم عند احداث شرخ بعمق 2 مم وعرضه 0.5 مم في منطقه الحام .. مما يوصلنا إلى اتخاذ الاجراءات الصيانه الملائمه تقادياً لحدوث الانهيارات وأيضاً يغدو بالامكان تقدير العمر المتبقي لتلك المواسير.
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