Damage tolerance and classic fatigue life prediction of a helicopter main rotor blade

Shahani, A.R.; Mohammadi, S.

doi:10.1007/s11012-015-0339-1

Cited by 12 publications

(5 citation statements)

References 10 publications

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“…An important aspect of helicopter maintenance and flight safety activities is the determination of blade life using fatigue stands and tests [3,10]. Fatigue is the process of localised, progressive, and permanent structural changes in one or more areas of the blade under stress that produce variations in stress and strain and may culminate in cracking or complete failure after a sufficient number of oscillations [11,12]. The vital components (blades) of the helicopter structure are subject to particularly rigorous testing, as they cannot be doubled and their failure can lead to serious accidents [13,14].…”

Section: Introductionmentioning

confidence: 99%

Manufacturing Process of Helicopter Tail Rotor Blades from Composite Materials Using 3D-Printed Moulds

Torpan,

Zaharia

2024

Applied Sciences

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Conventional processes require a mould for the manufacture of each test product, which often results in high costs but is ideal for large series of products. In contrast, for prototypes, additive manufacturing processes are a suitable low-cost time-saving alternative. The primary objective of this study is to investigate the capabilities of 3D-printed tooling in a real-life scenario for composite blades with low production numbers and prototypes in order to allow development and production costs to decrease and to also reduce lead times in the early phases of new projects. The 3D printing process is economically advantageous in terms of production costs for the composite blade mould, reducing the cost three times compared to the conventional manufacturing process. To obtain the composite helicopter blade, the following phases were carried out: the starting design of the mould, 3D printing and assembly of the mould sections, and blade manufacturing. The economic analysis of the two mould manufacturing methods shows an approximately equal ratio between the manufacturing costs of the 3D-printed mould and the manufacturing costs of the blade, whereas in the conventional processes, the costs for mould manufacturing represent 75% of the total cost and the rest (25%) of the cost is spent on blade manufacturing.

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Section: Introductionmentioning

confidence: 99%

Manufacturing Process of Helicopter Tail Rotor Blades from Composite Materials Using 3D-Printed Moulds

Torpan,

Zaharia

2024

Applied Sciences

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“…The authors found that failure starts from the root chord and tend toward the tip chord. Shahani & Mohammadi [2015] analyzed the fatigue life of a numerical blade using safe-life and damage tolerance approaches and concludes that the skin is the component that has the shortest lifetime.…”

Section: Introductionmentioning

confidence: 99%

Sensor Placement Optimization of a Helicopter Main Rotor Blade

Pereira¹,

Francisco²,

Jorge³

et al. 2022

Uncertainty Modeling: Fundamental Concepts and Models

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This chapter describes the importance of one of the major areas within Structural HealthMonitoring and Health and Usage Monitoring Systems: Sensor Placement Optimization (SPO). In this sense, the most important SPO metrics are presented and discussed with the reader. The methodological procedure of the optimization problem statement is also considered and discussed. he significance of rotary-wing aircraft, damages that can occur in the blade, works related to damage identification, modern methods and algorithms that have been used in this context, and a comprehensive SPO study for a helicopter main rotor blade will be presented. Finally, a new technique that considers the number of sensors as an objective associated with some of the main metrics used in SPO. The technique uses the Multiobjective Lichtenberg Algorithm and Feature Selection, an important area used in Data Mining.

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“…The use of repair is very common in aircraft, but in the helicopter industry (except in emergency cases 1,2 ), for dynamic components, repairs are usually not allowed and the part will be replaced. 3 There are several methods for repairing cracks or defects, including welding the defect site, using a rivet-attached metal patch, making a stop hole around or at the tip of the crack, or a combination of these methods. One of the best ways to repair cracks and defects in metal and composite structures is to use adhesively bonded composite patch repair.…”

Section: Introductionmentioning

confidence: 99%

The effect of disbond on the efficiency and durability of a composite patch repair in mode I and mixed mode considering different patch materials

Mohammadi

2022

Polymers and Polymer Composites

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In this paper, considering different parameters and various patch materials, the effect of disbond on the efficiency and durability of a composite patch repair is investigated in mode I and mixed-mode. One of the most important aspects of the composite patch repair is the bond strength. Repair patch disbond may occur at the patch edges or the crack site. At first, the effect of different parameters such as repair patch material and Young’s modulus and thickness of the adhesive on the efficiency and durability of the patch is investigated. Then, the effect of the disbond site on the stress intensity factor (patch efficiency) and adhesive stress (patch durability) is analyzed in both modes I and II. The results show that disbond at the crack site leads to a further reduction in patch efficiency compared to the patch edge disbond, but when separation occurs at the patch edge, the adhesive stress and the disbond growth rate are higher. Also, when 15% of the patch is separated in the crack site, for the longitudinal and transverse disbond modes, the mean KI is increased by 8 and 4%, respectively, compared to the state without disbond. Thus, the longitudinal disbond mode is more critical.

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Damage tolerance and classic fatigue life prediction of a helicopter main rotor blade

Cited by 12 publications

References 10 publications

Manufacturing Process of Helicopter Tail Rotor Blades from Composite Materials Using 3D-Printed Moulds

Manufacturing Process of Helicopter Tail Rotor Blades from Composite Materials Using 3D-Printed Moulds

Sensor Placement Optimization of a Helicopter Main Rotor Blade

The effect of disbond on the efficiency and durability of a composite patch repair in mode I and mixed mode considering different patch materials

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