Computation of Interaction Between Deepwater Risers: Collision Statistics and Stress Analysis

2002 ◽  
Author(s):  
Kjell Herfjord ◽  
Tore Holma˚s ◽  
Bernt Leira ◽  
Mads Bryndum ◽  
Tor Hanson
Keyword(s):  
Composite Material ◽  
Stress Analysis ◽  
Fatigue Damage ◽  
Material Properties ◽  
Relative Velocity ◽  
Post Processing ◽  
Time Step ◽  
Processing Operation ◽  
Deepwater Risers ◽  
Actual Stress

A methodology for computing the dynamics of interacting risers is presented. During the time simulations, riser impacts (if any) are recorded. The relative velocity and angle between the axes of the risers are recorded at each hit, so that the actual stress and accumulated fatigue damage may be computed in a post-processing operation. Detailed material properties, such as properties of coating, the actual composite material properties, etc. are used in that process. The methodology is based on a pre-established database of forces acting on the cylinders. At each time step, all riser elements are loaded with a combination of in-line and transverse forces, depending on local relative distance to the neighbouring riser. This imply that the methodology is based on quasi-static assumptions. The paper presents a validation of the computed force database by comparison with measured results. Examples of results from simulation with top tensioned risers on a TLP are given.

Advances in Tire Composite Theory

1973 ◽  
Vol 1 (2) ◽  
pp. 210-250 ◽  
Author(s):  
J. D. Walter ◽  
G. N. Avgeropoulos ◽  
M. L. Janssen ◽  
G. R. Potts
Keyword(s):  
Composite Material ◽  
Stress Analysis ◽  
Elastic Properties ◽  
Material Technology ◽  
Present Composite ◽  
Pneumatic Tires

Abstract Fundamentals of composite material technology are applied to the investigation of multi-ply cord-reinforced rubber systems as used in pneumatic tires. The stiffness parameters of such multi-ply systems are determined through the use of the elastic properties of the constituent cord and rubber components. The effects of coupling between the bending and stretching modes of deformation are discussed along with the limitations of present composite material technology as applied to soft rubbery systems. The predicted stiffness parameters are related to tread wear, obstacle envelopment, vibration, and stress analysis of tires.

Numerical analysis of damage zones in a bridge

2019 ◽  
Vol 11 (1) ◽  
pp. 1-12
Author(s):  
Mohammed Lamine Moussaoui ◽  
Mohamed Chabaat
Keyword(s):  
Numerical Analysis ◽  
Material Properties ◽  
Data File ◽  
Time Range ◽  
Bridge Structure ◽  
Time Step ◽  
Batch Mode ◽  
Content Type ◽  
Finite Element Software ◽  
Von Mises

Purpose The purpose of this paper is to present a numerical analysis of structural monitoring for damage zones detection. The study is performed with Ansys finite element software, which reads in batch mode programming a previously generated mesh data file and computes the transient dynamic solution for each time-step iteration within an analysis time range. Design/methodology/approach The approach itself is applied on a bridge structure which can be potentially subjected to damage zones due to severe loads cases and or earthquakes vibrations. The ideal Von Mises failure criterion ellipsoid envelope is applied for the detection of overstepped computed stresses and strains. Findings This numerical analysis allows computing, for each time-step iteration, the dynamic displacements at each degree of freedom and the corresponding stresses and strains inside the elements under the action of several times dependent loads cases. Practical implications Several simulations are considered to quantify the external loads. Originality/value The material properties of reinforced concrete RC are calculated for an existing specific bridge structure case. The RC strength is then introduced from the basic compounds material properties using the corresponding volumes fractions.

Development of an Acoustic-Based Riser Monitoring System

2009 ◽  
Author(s):  
Dai Wei ◽  
Yong Bai
Keyword(s):  
Gulf Of Mexico ◽  
Monitoring System ◽  
Fatigue Damage ◽  
Monitoring Systems ◽  
Design Tools ◽  
Complex Behavior ◽  
Maintenance And Repair ◽  
Future Design ◽  
Integrity Assurance ◽  
Deepwater Risers

Recent incidents with drilling risers in the Gulf of Mexico have led the industry’s application of more stringent integrity assurance requirements to its deepwater risers. Riser monitoring provides information that enables the operator to measure riser configurations and fatigue damage, confirm the integrity of the riser, assist with operational decisions, optimize inspection, maintenance and repair schedules /procedures and calibrate design tools. Monitoring can also improve the understanding of complex behavior of risers for the improvement to future design and analysis tools. This paper presents the characters of three different monitoring systems that suit specific objectives and requirements. An example project of acoustic approach is introduced with its working mode and design scheme.

Modeling and analysis of impact energy absorber by using ls dyna

2015 ◽  
Vol 12 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Adik Yadao ◽  
R. S. Hingole
Keyword(s):  
Impact Energy ◽  
Material Properties ◽  
Research Work ◽  
Cad Model ◽  
Post Processing ◽  
Passenger Compartment ◽  
Efficient Manner ◽  
Energy Absorber ◽  
Modeling And Analysis ◽  
Energy Absorbing

Today’s car is one of the most important things in everyone’s life .Every person wants to have his or her own car but the question that arises in each buyer’s mind is whether the vehicle is safe enough to spend so much of money so it is the responsibility of an mechanical engineer to make the vehical comfortable and at the Same time safer. Now a days automakers are coming with various energy absorbing devices such as crush box, door beams etc. this energy absorbing device s prove to be very useful in reducing the amount force that is being transmitted to the occupant. In this we are using impact energy absorber in efficient manner as compare to earlier. The various steps involved in this project starting from developing the cad model of this inner impact energy absorber using the CAD software CATIA V5 R19. Then pre-processing is carried out in HYPERMESH 11.0 which includes assigning material, properties, boundary conditions such as contacts, constraints etc. LS-DYNA971 is used as a solver and LS-POST is used for the post processing and results obtained are compared to the standards. By carrying out this idea it has been observed that there is a considerable amount of energy that is being absorbed by this energy-absorbing device. Along with this energy absorption, the intrusion in passenger compartment is also reduced by considerable amount. So for safer and comfortable car with inner impact energy absorber is one of the best options available. This will get implement by this research work.

Fatigue Assessment of Concrete Members Strengthened by FRP Materials

2014 ◽  
Vol 617 ◽  
pp. 221-224 ◽  
Author(s):  
Alena Čavojcová ◽  
Martin Moravcik
Keyword(s):  
Fatigue Damage ◽  
Cross Section ◽  
Theoretical Approach ◽  
Material Properties ◽  
Beam Cross Section ◽  
European Standard ◽  
Fatigue Assessment ◽  
Concrete Members ◽  
Damage Structure ◽  
T Beam

Fatigue and fatigue damage leads to a change in material properties that can lead to the element failures. Generally, it is necessary to verify the influence of the fatigue effects on the concrete members according to European standard EC2, [1]. FRP materials have been possibly used for the fatigue damage structure rehabilitation. There we can apply the condition of the limit boundaries stress on concrete and limit force in FRP material theoretical approach. Fatigue assessment will be analyzed for T-beam cross section with reinforcement and strengthened FPR material in this paper.

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