U22011 - Structural Integrity - University of Portsmouth

Instructions:

You are expected to start with a literature review on the background and recent developments of the subject, followed by a search for material data and test standards, which should help you with the quantitative assessments. The report should follow the following format: introduction, literature review, methods, analysis, discussion, conclusions and references; and should be written clearly in technical terms, using figures/tables as necessary. References must be given and cited in the text. The word limit for the report is 3000 words (each up to 1500 words, or approximately 5 pages A4).

Project I: Damage Tolerance Analysis of Aero-Engine Fan Blade

You have just joined an engineering consulting firm specialising in damage tolerance analysis. Your client, an aero-engine manufacturer, requested a fracture mechanics analysis of fan blade (Fig. 1).

Fig. 1. Aero-engines in production at Rolls-Royce plc

Specifically, they requested that the component is to be simplified as a centre-cracked panel and the centrifugal force experienced as uniformly distributed tensile stresses across the ends of the panel. Ti-6Al-4V is used currently, and a conservative estimate of an initial defect size from two independent NDT inspections found 2a=0.5 mm. W=0.5m. The client is interested in the following information:

Part 1. Would fatigue crack growth occur under an operational cyclic stress range -30 to 220 MPa? What if the maximum stress is increased by 50% whilst the stress range stays the same?

Part 2. If the component is sufficiently strong to sustain an overload of 5 times of the maximum nominal stress 220 MPa?

Part 3. When an inspection should be scheduled, if this must be done at 70% of component life predicted for a baseline loading cycle 0 - 220 MPa?

Part 4. What if this major cycle is superimposed with a vibrational minor cycle 200-240 MPa? Should the inspection period be revised?

Although not part of the client's briefing, your project manager suggested that you should also:

Part 5. Find the background information on fan blades of aero-engines, and the essential material information about Ti-6Al-4V and its properties from literature. In particular: Fatigue threshold, ⊗Kth; Paris Law parameters C and m: da/dN = C⊗Km and Fracture toughness K_c.

Part 6. Check if Small Scale Yielding (SSY) condition is satisfied in all the cases you calculated and comment on the results.

Part 7. Research alternative materials to Ti-6Al-4V for fan blades in aero-engines. Discuss the pros and cons of the alternative materials compared with Ti-6Al-4V. Comment on how damage tolerant assessments should be conducted if alternative materials are used.

Project II: Life assessment of high temperature header piping and tube system

The project aims for a life assessment of a high temperature steam header piping and tube system at a power generation plant. The client has requested a life assessment to be performed on one of their superheater header, as shown in Figure 2.1, which is a central manifold for other piping runs that is used to convert saturated or wet steam into superheated or dry steam.

Attachment:- Structural Integrity.rar