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Register a new userModeling of the fatigue crack initiation period on the helical gears
نمذجة فترة نشوء شقوق التعب الأولية على أسنان المسننات الحلزونية
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يقدم هذا البحث نموذج حسابي لفترة نشوء الشقوق الأولية بالتعب على أسنان المسننات الحلزونية, مع الأخذ بعين الاعتبار تأثير المعالجة الحرارية بالكربنة و الاحتكاك بين أسنان المسننات. و ذلك بهدف حساب عدد دورات التحميل اللازمة لنشوء هذه الشقوق, و دراسة تأثير السلوك الديناميكي على فترة عمل المسننات, بالاعتماد على نموذج ديناميكي للمسننات ثنائي درجة الحرية في الفتل و مقياس Papadopoulos للتعب باستخدام برنامج MatLab. تتم مقارنة النتائج الحاصلة مع نتائج التحليل الرياضي باستخدام طريقة الانفعال – عدد الدورات. تشير النتائج الحاصلة في هذا البحث إلى أن سرعة نشوء شق التعب الأولي تتعلق بقيم الاحتكاك بين سطوح المسننات و قيم الإجهادات المتبقية الناتجة عن المعالجة الحرارية, من جهة, و قيمة الحمل الديناميكي من جهة أخرى. حيث أن زيادة قيم الاحتكاك تنقص عدد دورات التحميل اللازم لنشوء الشق الأولي كما تنقل منطقة ظهوره باتجاه سطح أسنان المسننات و هذا التأثير معاكس لتأثير الإجهادات المتبقية التي تزيد عدد دورات التحميل.
A computational model of the fatigue crack initiation period on the helical gears ,with consideration of the heat treatment by carburization and friction effects, is presented. In order to calculate the number of stress cycles required for the appearance of the initial cracks, and study the influence of dynamic behavior. For this end, a dynamic model of gear with two freedom degrees in torsion developed in Matlab and fatigue criteria are used. The computational results are compared with those obtained using strain- life method. The obtained results show that appearance of initial fatigue crack depends strongly on the friction coefficient between the surfaces, heat treatment, and on the dynamic load.
References used
FRANCESCA, C. ANDREA, M. CARLO, R. Crack propagation behavior in planet gears. Procedia Structural Integrity. Vol. 2, 2016, p. 3610 – 3616
PODRUG, S. JELASKA, D. GLODEZ, S. Influence of different load models on gear crack path shapes and fatigue lives. Fatigue & Fracture of Engineering Materials & Structure, Vol. 31, 2008, p. 327-339
FAJDIGA, G. SRAMEL, M. Fatigue crack initiation and propagation under cyclic contact loading. Engineering Fracture Mechanics, Vol. 76, 2009, p.1320-1335
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