Residual Strength Optimisation of a Vent Hole in an Aircraft Component Using a Heuristic Method

2011 ◽  
Vol 275 ◽  
pp. 105-108
Author(s):  
Raj Das ◽  
Rhys Jones
Keyword(s):  
Residual Strength ◽  
Damage Tolerance ◽  
Heuristic Method ◽  
Initial Crack ◽  
Shape Optimisation ◽  
Initial Shape ◽  
Fuel Flow ◽  
Component Design ◽  
Aircraft Component ◽  
Tolerance Optimisation

The paper presents application of damage tolerance optimisation principles to the design of industrial components. It is illustrated via design optimisation of a Fuel Flow Vent Hole (FFVH) located in the Wing Pivot Fitting (WPF) of an F-111 aircraft. The aim is to determine the shape of the cutout that will maximise its residual strength under the operating loading conditions. Damage tolerance shape optimisation is performed using a heuristic optimisation method known as the ‘Biological algorithm’. The maximum stress intensity factor (SIF) for all of the cracks around the boundary of the optimal cutout is found to be significantly lower compared to that of the initial shape. This shows that an improved residual (fracture) strength is achieved for the optimal designs. The variability in SIF around the cutout boundary is reduced, thereby making the shape more evenly fracture critical. The shapes of the residual strength optimal vent holes are found to depend on the initial crack sizes. It is also shown that a damage tolerance optimisation additionally produces a lighter WPF component design, which is highly desirable for aerospace industries.

AN ANALYSIS OF THE DAMAGE TOLERANCE OF LIGHT AIRCRAFT LANDING GEAR

2013 ◽  
Vol 37 (4) ◽  
pp. 1147-1159 ◽  
Author(s):  
Pu-Woei Chen ◽  
Shu-Han Chang ◽  
Jyun-Yuan Siao
Keyword(s):  
Life Cycle ◽  
Damage Tolerance ◽  
Life Time ◽  
Initial Crack ◽  
Landing Gear ◽  
Finite Element Software ◽  
Aircraft Landing ◽  
Aircraft Landing Gear ◽  
The Relationship

This study uses the finite element software, FRANC2D, and the life-time analysis software, AFGROW, to perform simulation analyses of the damage tolerance of the landing gear of light aviation vehicles. This study explores the effect that the initial crack positions and different materials have on the life cycle of landing gear under long-term loads. This study also compares the relationship between stress intensity factors and crack growth for four types of aluminum alloys, titanium alloy and alloy steel. The relationship between residual strength and life cycle, in the presence of existing cracks, is also investigated.

Impact Damage Tolerance and Fatigue Durability of GLARE Laminates

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Hyoungseock Seo ◽  
H. T. Hahn ◽  
Jenn-Ming Yang
Keyword(s):  
Residual Strength ◽  
Impact Test ◽  
Damage Tolerance ◽  
Impact Damage ◽  
Fatigue Behavior ◽  
Energy Levels ◽  
Damage Initiation ◽  
Fatigue Durability ◽  
Weight Impact ◽  
The Impact

The fatigue behavior and residual strength of postimpacted GLARE 4-3/2, GLARE 5-2/1, and monolithic aluminum 2024-T3 alloy were investigated experimentally. Drop-weight impact was applied at a variety of energy levels to inflict a barely visible impact damage, a clearly visible impact damage, and a penetration damage. After the impact test, constant-amplitude tension-tension fatigue was done to delineate the modes of damage initiation and growth and the effect of damage on fatigue life and residual strength. The results showed that GLARE laminates exhibit superior postimpact fatigue durability when compared with the monolithic 2024-T3 aluminum alloy.

Indication, Measurement and Control of Ice Accretion

1951 ◽  
Vol 55 (486) ◽  
pp. 382-385 ◽  
Author(s):  
D. F. Lucking
Keyword(s):  
Collection Efficiency ◽  
Meteorological Factor ◽  
Material Surface ◽  
Ice Accretion ◽  
Component Design ◽  
Aircraft Component ◽  
Design Characteristics ◽  
The One ◽  
And Control ◽  
Measurement And Control

The rate of ice accretion on an aircraft depends upon meteorological factors and aircraft characteristics. There are on the one hand atmospheric pressure and temperature; water content; droplet size; electrostatic conditions. On the other hand, there is the collection efficiency made up of aircraft component design characteristics such as size; shape; material; surface finish. Finally, there are aircraft flight variables such as speed; attitude; skin temperature; vibratory state.Meteorologists are able to define potential icing intensity if they can forecast the ambient factors mentioned. The intensity may be defined as light, moderate, or severe, or by some such broad adjective, with reference to a hypothetical collector. Similarly, the air-worthiness authority, e.g. the Air Registration Board, must be satisfied that an aircraft can be operated safely in the appropriate meteorological conditions. Therefore the probable association of each meteorological factor with the others needs to be known.

scholarly journals Role of Initial Crack Tip Shape, Plastic Compressibility and Strain Softening on Near-Tip Stress-Strain State in Fatigue Cracks during Simulation of a Finite Deformation based Elastic-Viscoplastic Constitutive Model

2021 ◽  
Author(s):  
Md Intaf ALAM ◽  
Debashis KHAN ◽  
Satyabrat PANDEY ◽  
Sandeep KUMAR
Keyword(s):  
Crack Growth ◽  
Strain Softening ◽  
Fatigue Cracks ◽  
Crack Tip ◽  
Initial Crack ◽  
Small Scale ◽  
Curvature Radius ◽  
Stress Strain ◽  
Initial Shape ◽  
Hardening Material

This paper deals with the effect of initial crack tip shape, plastic compressibility, and strain softening on near-tip stress-strain fields for a mode I crack subjected to fatigue loading under plane strain and small scale yielding. A finite strain-based elastic-viscoplastic constitutive equation with bilinear hardening and hardening-softening-hardening hardness functions is taken up for simulation. It is observed that plastic compressibility and strain softening have a significant impact on crack tip opening displacement (CTOD) and tip propagation. Furthermore, it has been viewed that the initial shape of a crack tip can significantly influence both the CTOD and the crack tip extension for the bilinear hardening material; however, with identical conditions for the hardening-softening-hardening material, the initial crack tip shape affects the fatigue crack growth much lesser though the CTOD is influenced considerably. In comparison to the crack growth in the plastically incompressible hardening-softening-hardening solids, the variation of the crack growth (with respect to the tip curvature radius) is more and peculiar in the corresponding plastically compressible solid. To explain and to get a better insight of the crack tip deformation, the near-tip plastic strain and hydrostatic stress have been illustrated.

Study on Damage Tolerance of Composite Laminates with Hole or Crack

2014 ◽  
Vol 1037 ◽  
pp. 16-19
Author(s):  
Wu Wen Yao ◽  
Ping Zhou ◽  
Sheng Li Hou ◽  
Ming Wu Tu
Keyword(s):  
Residual Strength ◽  
Composite Laminates ◽  
Damage Tolerance ◽  
Composite Component ◽  
Damage Repair

By means of computation and analysis of damage tolerance of composite laminates with hole or crack, the conclusion is brought forth that crack on laminates can’t be cut into hole to improve the residual strength; otherwise the damage will become more serious. The method and conclusion can be reference and basis for battle damage repair of airplane composite component.

Research on Crack Growth Life and Sensibility Analysis of Influence Parameters in Crack Growth Life

2011 ◽  
Vol 317-319 ◽  
pp. 207-210 ◽  
Author(s):  
Wen Lin Liu ◽  
Wei Han ◽  
Zhi Tao Mu ◽  
Xiu Xia Wang ◽  
Da Zhao Yu
Keyword(s):  
Crack Growth ◽  
Damage Tolerance ◽  
Influence Factors ◽  
Initial Crack ◽  
Model Parameters ◽  
Main Rotor ◽  
Safe Operation ◽  
Input Parameters ◽  
Sensibility Analysis ◽  
Crack Growth Model

It requires a damage tolerance assessment for all airframes and engines to set the inspection windows for safe operation. A certain rotorcraft main rotor yoke were analyzed with NASGRO model. The sensibility analysis of influence parameters in crack growth life has been done. In order to calculate the sensibility index of influence factors to crack growth life, the factors were divided into input parameters and crack growth model parameters. The results show that the input parameters have the following precedence ordering: fatigue crack growth threshold, fracture spectrum, initial crack, fracture toughness, the sensibility values are 11.25, 8.5417, 0.8333, 0.1125, respectively. The NASGRO model parameters have the following precedence ordering: n, p, C, q. the sensibility values are 6.0417, -3.9583, 1.25, 0.1812, respectively.

scholarly journals Bird and hail stone impact resistance analysis on a jet engine composite air inlet

2018 ◽  
Vol 188 ◽  
pp. 04006
Author(s):  
Radek Doubrava ◽  
Martin Oberthor ◽  
Petr Bělský ◽  
Jan Raška
Keyword(s):  
Numerical Simulation ◽  
Impact Resistance ◽  
Point Of View ◽  
Test Results ◽  
Air Inlet ◽  
Component Design ◽  
Aircraft Component ◽  
Physical Impact ◽  
The Cost ◽  
New Generation

Bird or hail stone impacts are an important phenomenon that must be taken into consideration when designing aircraft. As engines are the sole thrust-providing mechanisms of an aircraft, it is critical that the effects of bird or hail stone strikes on engine inlets and systems be investigated and mitigated to the greatest extent possible. A combination of experiments and numerical simulations is necessary to properly understand the behaviour of a bird or hail stone during impact and the reaction of the impacted material with the structure. A simulation methodology is developed and validated to certify the bird or hail stone strike resistance of composite air ducts designed for a new generation of jet training aircraft. Physical impact tests were performed on real composite parts. Numerical simulation results were compared with test results. Numerical simulation was also used for test preparation and optimization of the test rig design from the point of view of the influence of the stiffness of the surrounding aircraft structure. The validated modelling procedure allows the analysis of numerous impact scenarios, improving the optimization procedures for aircraft component design and reducing the cost of development by reducing the need to manufacture test prototypes.

Sign in / Sign up

Export Citation Format

Share Document