scholarly journals Design and Test of a Blast Shield for Boeing 737 Overhead Compartment

2006 ◽  
Vol 13 (6) ◽  
pp. 629-650 ◽  
Author(s):  
Xinglai Dang ◽  
Philemon C. Chan
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Field Tests ◽  
Element Model ◽  
Design Criterion ◽  
Structural Failure ◽  
Commercial Aircraft ◽  
Structural Connections ◽  
Fuselage Skin ◽  
Passenger Aircraft

This work demonstrates the feasibility of using a composite blast shield for hardening an overhead bin compartment of a commercial aircraft. If a small amount of explosive escapes detection and is brought onboard and stowed in an overhead bin compartment of a passenger aircraft, the current bins provide no protection against a blast inside the compartment. A blast from the overhead bin will certainly damage the fuselage and likely lead to catastrophic inflight structural failure. The feasibility of using an inner blast shield to harden the overhead bin compartment of a Boeing 737 aircraft to protect the fuselage skin in such a threat scenario has been demonstrated using field tests. The blast shield was constructed with composite material based on the unibody concept. The design was carried out using LS-DYNA finite element model simulations. Material panels were first designed to pass the FAA shock holing and fire tests. The finite element model included the full coupling of the overhead bin with the fuselage structure accounting for all the different structural connections. A large number of iterative simulations were carried out to optimize the fiber stacking sequence and shield thickness to minimize weight and achieve the design criterion. Three designs, the basic, thick, and thin shields, were field-tested using a frontal fuselage section of the Boeing 737–100 aircraft. The basic and thick shields protected the integrity of the fuselage skin with no skin crack. This work provides very encouraging results and useful data for optimization implementation of the blast shield design for hardening overhead compartments against the threat of small explosives.

Aerodynamic Analysis in Time Domain of a Cable-Stayed Bridge

2012 ◽  
Vol 479-481 ◽  
pp. 1205-1208
Author(s):  
Chern Hwa Chen ◽  
Yuh Yi Lin ◽  
Cheng Hsin Chang ◽  
Shun Chin Yang ◽  
Yung Chang Cheng ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Time Domain ◽  
Field Tests ◽  
Element Model ◽  
Modal Identification ◽  
Dynamic Responses ◽  
Cable Stayed Bridge ◽  
The Time Domain ◽  
Frequency Domain Approach

To determine its actual dynamic responses under the wind loads, modal identification from the field tests was carried out for the Kao Ping Hsi cable-stayed bridge in southern Taiwan. The rational finite element model has been established for the bridge. With the refined finite element model, a nonlinear analysis in time domain is employed to determine the buffeting response of the bridge. Through validation of the results against those obtained by the frequency domain approach, it is confirmed that the time domain approach adopted herein is applicable for the buffeting analysis of cable-stayed bridges.

EXPERIMENTAL MODAL TEST AND TIME-DOMAIN AERODYNAMIC ANALYSIS OF A CABLE-STAYED BRIDGE

2011 ◽  
Vol 11 (01) ◽  
pp. 101-125 ◽  
Author(s):  
C. H. CHEN ◽  
C. I. OU
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Time Domain ◽  
Field Tests ◽  
Element Model ◽  
Modal Identification ◽  
Dynamic Responses ◽  
Element Analysis ◽  
Cable Stayed Bridge ◽  
The Time Domain

To determine its actual dynamic responses under the wind loads, modal identification from the field tests was carried out for the Kao Ping Hsi cable-stayed bridge in southern Taiwan. The dynamic characteristics of the bridge identified by a continuous wavelet transform algorithm are compared with those obtained by the finite element analysis. The finite element model was then modified and refined based on the field test results. The results obtained from the updated finite element model were shown to agree well with the field identified results for the first few modes in the vertical, transverse, and torsional directions. This has the indication that a rational finite element model has been established for the bridge. With the refined finite element model, a nonlinear analysis in time domain is employed to determine the buffeting response of the bridge. Through validation of the results against those obtained by the frequency domain approach, it is confirmed that the time domain approach adopted herein is applicable for the buffeting analysis of cable-stayed bridges.

Validation of a Computer Model for Flexible Pipe Crushing Resistance Calculations

2008 ◽  
Author(s):  
Aline Malcorps ◽  
Antoine Felix-Henry
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Plastic Material ◽  
Load Capacity ◽  
Permanent Deformation ◽  
Element Model ◽  
Design Criterion ◽  
Internal Diameter ◽  
Flexible Pipe ◽  
Offshore Field

Several types of laying equipments are used to install flexible pipelines for offshore field developments. These pipelines installation tools apply generally compressive radial forces to hold the pipe suspended weight. The deeper the pipeline has to be laid, the higher is its suspended weight and therefore the higher these radial loads need to be. As each flexible pipe construction is optimized for each field application, a design methodology is necessary to be able to evaluate the radial load acceptable by the flexible pipe. The failure mode associated with this type of loads is an instability thought to be similar to the hydrostatic collapse mode. Therefore an adequate design safety factor has to be considered. The water depth of offshore field developments becoming ever deeper, the resistance of the flexible pipe to installation loads becomes often a driving design criterion. A finite element model to address this type of loading has been developed and improved over the past years. To avoid over-sizing the flexible pipe with current design approach, this finite element model needed to be improved for the latest materials used and for higher crushing loads. To this effect, a new powerful test bench with a crushing load capacity of 1200 tons over one meter has been designed, procured and is now operational. It can handle pipes from 4" to 19" internal diameter. Many types of flexible pipe samples have been tested up to permanent deformation using bi-, tri- and quadri-caterpillar tensioners. The results of these tests have been used to validate a new finite element model using in particular non-linear elasto-plastic material laws. In this paper, several test results will be presented and compared with the calculations. The relevance of different possible design criteria depending on the type of loading regime, the slenderness of the pipe and the number of radially resistant layers, will also be discussed. This new model is operational and allows to optimize the flexible pipe design in particular for ultra-deep water applications down to 2500m or more.

2000-hp Motor Support Structure Vibration Sensitivity: Tests, Finite Element Analysis, and Suggested Strategies for Prevention

1984 ◽  
Vol 106 (1) ◽  
pp. 113-121 ◽  
Author(s):  
R. B. Power ◽  
D. E. Wood
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Transfer Functions ◽  
Field Tests ◽  
Steel Structure ◽  
Element Model ◽  
Mode Shapes ◽  
Element Analysis ◽  
Extensive Field ◽  
Procurement Strategies

High vibration was detected during startup of three 2000-hp motors driving critical service compressors. A system natural frequency was close to the running speed. Extensive field tests were conducted; rotor dynamics were studied; and a simple finite element model was made to include the rotor, bearing oil film, motor frame, supporting steel structure, and concrete foundation. Results from the finite element model correlated well with field tests in the areas of natural frequencies, mode shapes, frequency shifts caused by changes in test conditions, transfer functions, and sensitivity to rotor unbalance. Design and procurement strategies to prevent or control future similar problems are proposed.

scholarly journals Static and dynamic evaluation of a butterfly-shaped concrete-filled steel tube arch bridge through numerical analysis and field tests

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110446
Author(s):  
Gang Wu ◽  
Wei-Xin Ren ◽  
Ya-Fei Zhu ◽  
Syed M Hussain
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Element Model ◽  
Field Tests ◽  
Element Model ◽  
Steel Tube ◽  
Model Errors ◽  
Arch Bridge ◽  
Concrete Filled Steel Tube ◽  
Cfst Arch Bridge

The butterfly-shaped concrete-filled steel tube (CFST) arch bridge is an irregular bridge with unique esthetics. In this paper, this new shape of CFST arch bridge is introduced, and a refined three-dimensional finite element model (FEM) is established to evaluate static and dynamic behavior of the bridge. In order to reduce model errors, the FEM is calibrated according to numerical analysis and field tests. Static calculation results show that the butterfly-shaped bridge has good structural performance. The bending moment and axial force of the arch ribs increase when the camber angle of suspender changing from 15° to 50°. Dynamic test is carried out by ambient vibration testing under traffic and wind-induced excitations. The modal parameters of the bridge were calculated by the stochastic subspace identification method in the time domain. In terms of natural frequencies and mode shapes, the FEM analysis was validated by experimental modal analysis. The updated model thus obtained can be treated as a baseline finite element model, which is suitable for long term monitoring and safety evaluation of the structure in different severe circumstances such as earthquakes and wind loading in future.

Fibre-Reinforced Polymers under Impact Load

2006 ◽  
Vol 326-328 ◽  
pp. 1563-1568 ◽  
Author(s):  
Ch.R. Koenig ◽  
D.H. Mueller ◽  
J. Mueller ◽  
Mircea Calomfirescu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Impact Load ◽  
Composite Plates ◽  
Element Model ◽  
Structural Failure ◽  
Reinforced Polymers ◽  
The University ◽  
The Impact ◽  
The Finite Element Model

Structural failure of fibre-reinforced polymers (FRP) caused by impact is an important factor in product development for the aircraft industry. Therefore it is necessary to obtain knowledge of the mechanisms and of the material loading during and shortly after an impact load. On account of this a Finite-Element-Model was developed with the goal to deduce design rules for impact tolerant composite materials. To verify and validate the Finite-Element-Model it is essential to have information of the state of stress on the surface of the FRP shortly after the impact. An impact test device was developed at the University of Bremen. The time variable, stress and strain conditions in composite plates are measured using photoelastic technique, strain gauges and holographic interferometry.

scholarly journals New Command Mechanism of Flaps and Wings of a Light Sport Aircraft

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 221
Author(s):  
Ion-Marius Ghiţescu ◽  
Maria Luminita Scutaru ◽  
Marilena Ghiţescu ◽  
Paul Nicolae Borza ◽  
Marin Marin
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Fuel Economy ◽  
Element Model ◽  
Point Of View ◽  
Commercial Aircraft

Commercial aircraft have well-designed and optimized systems, the result of a huge experience in the field, due to the large fleet of aircraft in operation. For light, utility, or sports aircraft, with a multitude of shapes, tasks, and construction types, there are different solutions that seek to best meet the requirements of the designed aircraft. In this sense, for a sport plane, an increased maneuverability is desired, and the system that controls flaps and wing must be properly designed. A new flap mechanism command solution is proposed and justified in the paper, for use in sports and recreational aviation, in order to achieve angles of braking greater than 40°, take-off and landing in a shorter time and over a shorter distance, as well as the gliding of the aircraft in critical flight conditions or when fuel economy is needed. A finite element model is used to verify the optimized command system for the flap and wing and to check if the strength structure of the aircraft is properly designed. The main result consists of the new design command system for flaps and wings and in verifying, by calculation, the acceptability of the new mechanism proposed from the point of view of the strength of the materials.

Sign in / Sign up

Export Citation Format

Share Document