On the Influence From Hydrodynamic Forces on Speed and Footprint for a Falling Riser

2004 ◽  
Author(s):  
Vidar Berntsen ◽  
Carl M. Larsen ◽  
Elizabeth Passano ◽  
Nilo De Moura Jorge ◽  
Jose´ Roberto
Keyword(s):  
Material Model ◽  
Model Material ◽  
Model Parameters ◽  
Analysis Method ◽  
Hydrodynamic Load ◽  
Stochastic Variation ◽  
Dynamic Simulations ◽  
Load Model ◽  
Parameter Variations ◽  
The Impact

This paper presents analysis method and key results from dynamic simulations of a drilling riser on 1900 metres water depth after release of upper end. Key results are the geometry of the collapsed riser on the seafloor (footprint) and the impact speed of the riser when hitting the seafloor. The purpose of the study has been to investigate the influence on the results from operational and model parameters such as vessel offset relative to the riser base, current speed, hydrodynamic load model, material model and interaction between the riser and the seafloor. The main conclusion from the study is that most trends from parameter variations are weak and often overshadowed by a more stochastic variation caused by the inherent complexity of the mechanical behaviour during collapse.

Phenomenological Modeling of Carpeted Surface for Drop Simulation of Portable Electronics

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Abhi Sirimamilla ◽  
Hua Ye ◽  
Yinan Wu
Keyword(s):  
Mechanical Response ◽  
Viscoelastic Model ◽  
Single Layer ◽  
Material Model ◽  
Impact Testing ◽  
Consumer Electronics ◽  
Model Parameters ◽  
Portable Devices ◽  
Impact Surface ◽  
The Impact

Using finite element (FE) analysis to simulate drop impact is widely adopted by the consumer electronics industry in the design process of portable devices. Most of such simulations model impact surface as a rigid or simple elastic surface. While this approach is valid for many common hard surfaces such as wood, tile, or concrete, it often does not provide a realistic risk assessment if the impact surface is a soft surface such as carpet. This paper describes a methodology to create a material model for carpeted impact surface that is suited for FE drop simulation. A multilayer hyperelastic–viscoelastic material model is used to model the mechanical response of the carpet under mechanical impact. Quasi-static and impact testing on the industrial carpet were performed to calibrate the model parameters with the help of optimization. Validation of the model was done by comparing the simulation predictions with measurements from the impact tests performed at different heights. Much better correlation between experimental measurements and simulation predictions were observed when using the multilayer hyper-viscoelastic model for carpet than using a single layer homogenous model. This approach can provide a better estimate and a more accurate representation for device drop risk on carpeted surfaces for design and development of portable products. The methodology can also be used to derive material models for other similar impact surfaces.

Effect of Critical Void Volume Fraction fF on Results of Ductile Fracture Simulation for S235JR Steel under Multi-Axial Stress States

2014 ◽  
Vol 598 ◽  
pp. 113-118 ◽  
Author(s):  
Paweł Grzegorz Kossakowski ◽  
Wiktor Wciślik
Keyword(s):  
Volume Fraction ◽  
Axial Stress ◽  
Material Model ◽  
Model Parameters ◽  
Material Microstructure ◽  
Fracture Simulation ◽  
Critical Volume Fraction ◽  
Stress States ◽  
The Impact ◽  
Critical Void

The article describes an example of the GTN material model parameters determination and application. The main objective of the study was to determine experimentally the value of the critical volume fraction of voids fFfor S235JR steel and to assess the impact of this parameter on the numerical force-elongation curve under the multi-axial stress state. Value of fFwas obtained by the quantitative analysis of the material microstructure at fracture surfaces. For a sake of comparison, two other values of fF, described in the literature, were also used in numerical simulations.

scholarly journals NUMERICAL MODELLING OF BIRD STRIKE ON A ROTATING ENGINE BLADES BASED ON VARIATIONS OF POROSITY DENSITY

2022 ◽  
Vol 23 (1) ◽  
pp. 412-423
Author(s):  
Sharis-Shazzali Shahimi ◽  
Nur Azam Abdullah ◽  
Ameen Topa ◽  
Meftah Hrairi ◽  
Ahmad Faris Ismail
Keyword(s):  
Numerical Modelling ◽  
Structural Integrity ◽  
Constitutive Relations ◽  
Material Model ◽  
Initial Stresses ◽  
Model Parameters ◽  
Bird Strike ◽  
Elastic Plastic ◽  
Engine Blade ◽  
The Impact

A numerical investigation is conducted on a rotating engine blade subjected to a bird strike impact. The bird strike is numerically modelled as a cylindrical gelatine with hemispherical ends to simulate impact on a rotating engine blade. Numerical modelling of a rotating engine blade has shown that bird strikes can severely damage an engine blade, especially as the engine blade rotates, as the rotation causes initial stresses on the root of the engine blade. This paper presents a numerical modelling of the engine blades subjected to bird strike with porosity implemented on the engine blades to investigate further damage assessment due to this porosity effect. As porosity influences the decibel levels on a propeller blade or engine blade, the damage due to bird strikes can investigate the compromise this effect has on the structural integrity of the engine blades. This paper utilizes a bird strike simulation through an LS-Dyna Pre-post software. The numerical constitutive relations are keyed into the keyword manager where the bird’s SPH density, a 10 ms simulation time, and bird velocity of 100 m/s are all set. The blade rotates counter-clockwise at 200 rad/s with a tetrahedron mesh. The porous regions or voids along the blade are featured as 5 mm diameter voids, each spaced 5 mm apart. The bird is modelled as an Elastic-Plastic-Hydrodynamic material model to analyze the bird’s fluid behavior through a polynomial equation of state. To simulate the fluid structure interaction, the blade is modelled with Johnson-Cook Material model parameters of aluminium where the damage of the impact can be observed. The observations presented are compared to previous study of a bird strike impact on non-porous engine blades. ABSTRAK: Penyelidikan berangka telah dijalankan ke atas bilah enjin berputar tertakluk kepada impak pelanggaran burung. Pelanggaran burung tersebut telah dimodelkan secara berangka sebagai silinder gelatin dengan hujungnya berbentuk hemisfera demi mensimulasikan impaknya ke atas bilah enjin yang berputar. Pemodelan berangka bilah-bilah enjin yang berputar tersebut menunjukkan bahawa pelanggaran burung mampu menyebabkan kerosakan teruk terhadap bilah enjin terutamanya apabila bilah enjin sedang berputar oleh sebab putaran menghasilkan tekanan asal di pangkal bilah enjin. Kajian ini mengetengahkan pemodelan berangka ke atas bilah-bilah enjin tertakluk kepada pelanggaran burung terhadap bilah-bilah enjin yg mempunyai keliangan demi menyelidik dan menilai kerosakan kesan daripada keliangan tersebut. Keliangan juga mempengaruhi tahap-tahap desibel ke atas bilah kipas ataupun bilah enjin, kerosakan hasil serangan burung boleh menterjemah tahap ketahanan struktur integriti bagi bilah-bilah enjin tersebut. Penyelidikan ini mengguna pakai perisian “LS-Dyna Pre-post” untuk simulasi pelanggaran burung. Hubungan konstitutif berangka telah dimasukkan sebagai kata kunci di mana ketumpatan SPH burung, masa simulasi 10ms, dan halaju burung ditetapkan kepada 100 m/s. Bilah tersebut berputar pada 200 rad/s arah lawan jam dengan jejaring tetrahedron. Kawasan berliang atau kosong di sepanjang bilah ditetapkan diameternya kepada 5 mm, dan dijarakkan 5 mm di antara satu sama lain. Burung pula dimodelkan sebagai material “Elastic-Plastic-Hydrodynamic” untuk mengkaji sifat bendalir burung melalui persamaan polinomial. Demi mensimulasi interaksi struktur bendalir, bilah tersebut dimodelkan sebagai parameter aluminium material “Johnson Cook” di mana kerosakan daripada impak tersebut dapat diteliti. Penelitian-penelitian tersebut dibandingkan dengan kajian terdahulu ke atas serangan burung terhadap bilah-bilah enjin tidak berliang.

Dynamic Simulation of Free-Spanning Pipeline Trawl Board Pull-Over

2011 ◽  
Author(s):  
Vegard Longva ◽  
Svein Sævik ◽  
Erik Levold ◽  
Ha˚var Ilstad ◽  
Per Teigen
Keyword(s):  
Finite Element ◽  
Forward Speed ◽  
Finite Element Analyses ◽  
Analysis Method ◽  
Hydrodynamic Load ◽  
Drag Coefficients ◽  
Load Model ◽  
Dynamic Mass ◽  
Hydrodynamic Loading ◽  
Heading Angle

The main objective of this effort was to examine if finite element analyses can be used to predict pull-over loads from a trawl board. Here the trawl board was represented by a 6-DOF hydro-dynamic load model, where the mass and drag coefficients are expressed as functions of seabed gap, seabed inclination angle and heading angle. Both seabed proximity and forward-speed effects of the trawl board are hence included. The applied drag coefficients were established by model testing, while the hydro-dynamic mass was found by potential theory calculations. Compared to previous efforts, the hydrodynamic loading on the trawl board is represented in a far more consistent way in this paper. A simulation model which contained a polyvalent trawl board and a free-spanning pipeline was established. Several simulations were performed with span heights between 0 m and 2 m. In all simulations the pull-over force and pipeline response was sampled. The sampled results were thereafter validated by means of the analysis method and pull-over loading proposed in the DNV-RP-F111 code. Some differences could be observed in the response histories, but in summary the numerical model predicts a realistic pull-over. This indicates that the applied hydrodynamic load model captures the relevant effects during the pullover.

Sensitivity Analysis of Concrete Face Rock-Fill Dam Parametric Based on the Intelligent Algorithm

2014 ◽  
Vol 580-583 ◽  
pp. 1940-1945
Author(s):  
Qiao Yan ◽  
Zhan Hong Gao ◽  
Zhi Cheng Song
Keyword(s):  
Sensitivity Analysis ◽  
Orthogonal Design ◽  
Model Parameters ◽  
Analysis Method ◽  
Range Analysis ◽  
Unknown Parameters ◽  
Rock Fill ◽  
Dam Deformation ◽  
Parameters Inversion ◽  
The Impact

Sensitivity analysis of model parameters is a rock fill parametric inversion analysis method to determine the unknown parameters. Traditional sensitivity analysis is basically a lot of trial or the method of single factor analysis based on a large amount of calculation, but, unable to reflect the real situation. The method of particle swarm optimization based on neural network based nonlinear mapping relationship between model parameters and displacement to finite element simulation of dam deformation. Basing on the orthogonal design, the methods of range analysis and variance analysis method were used for sensitivity analysis of the parameters of Duncan E-B model and the impact of various parameters on the dam displacement, and then it can be as the parameters of rock fill dam provide basis for determining the unknown parameters inversion.

Modeling of Tread Block Contact Mechanics Using Linear Viscoelastic Theory3

2008 ◽  
Vol 36 (3) ◽  
pp. 211-226 ◽  
Author(s):  
F. Liu ◽  
M. P. F. Sutcliffe ◽  
W. R. Graham
Keyword(s):  
High Speed ◽  
Slip Rate ◽  
Material Model ◽  
Contact Forces ◽  
Block Modeling ◽  
Rate Dependent ◽  
Linear Viscoelastic Material ◽  
Linear Viscoelastic ◽  
The Impact ◽  
Good Agreement

Abstract In an effort to understand the dynamic hub forces on road vehicles, an advanced free-rolling tire-model is being developed in which the tread blocks and tire belt are modeled separately. This paper presents the interim results for the tread block modeling. The finite element code ABAQUS/Explicit is used to predict the contact forces on the tread blocks based on a linear viscoelastic material model. Special attention is paid to investigating the forces on the tread blocks during the impact and release motions. A pressure and slip-rate-dependent frictional law is applied in the analysis. A simplified numerical model is also proposed where the tread blocks are discretized into linear viscoelastic spring elements. The results from both models are validated via experiments in a high-speed rolling test rig and found to be in good agreement.

Estimating OLED Display Device Lifetime from pixel and screen brightness and its application

2019 ◽  
Vol 2019 (1) ◽  
pp. 331-338 ◽  
Author(s):  
Jérémie Gerhardt ◽  
Michael E. Miller ◽  
Hyunjin Yoo ◽  
Tara Akhavan
Keyword(s):  
Image Processing ◽  
Power Consumption ◽  
Model Parameters ◽  
Display Device ◽  
Image Processing Algorithm ◽  
Pixel Value ◽  
Device Lifetime ◽  
The Impact ◽  
Oled Display

In this paper we discuss a model to estimate the power consumption and lifetime (LT) of an OLED display based on its pixel value and the brightness setting of the screen (scbr). This model is used to illustrate the effect of OLED aging on display color characteristics. Model parameters are based on power consumption measurement of a given display for a number of pixel and scbr combinations. OLED LT is often given for the most stressful display operating situation, i.e. white image at maximum scbr, but having the ability to predict the LT for other configurations can be meaningful to estimate the impact and quality of new image processing algorithms. After explaining our model we present a use case to illustrate how we use it to evaluate the impact of an image processing algorithm for brightness adaptation.

ANALISIS PENGARUH PEMBANGUNAN JALAN LAYANG JANTI TERHADAP PERKEMBANGAN TATA RUANG KAWASAN JANTI STUDI KASUS : KAWASAN JANTI, DESA CATURTUNGGAL, KABUPATEN SLEMAN, D. I. YOGYAKARTA

2017 ◽  
Vol 11 (3) ◽  
pp. 255
Author(s):  
Jeky El Boru
Keyword(s):  
Road Network ◽  
Open Space ◽  
Qualitative Description ◽  
Analysis Method ◽  
Open Spaces ◽  
The Road ◽  
Before And After ◽  
Linkage Method ◽  
The Impact ◽  
Parking Place

Abstract: This research aims to analyze the impact of Janti Flyover Construction toward the growth of layout at Janti Urban Area, including structured space, open space, and linkage. Method used for data collecting are observation, air photograph monitoring, and interview, whereas the analysis method is qualitative description, which is the superimposed method of two layers, that are the layout condition before and after flyover construction. The result shows that the impact of Janti Flyover construction can be seen on building mass (solid), the increasing number of open spaces, including the road network, parking place, and park, whereas the relation between spaces, visually and structurally, can be seen on the growth of buildings which have new shapes and styles, therefore the performance of the overall building does not have a proportional shape. Considering Janti Street at the collective relation, its role is getting stronger as the main frame road network.Keywords: Flyover construction, layout changing, Janti AreaAbstrak: Penelitian ini bertujuan untuk menganalisis pengaruh pembangunan Jalan Layang Janti terhadap perkembangan tata ruang Kawasan Janti, meliputi ruang terbangun, ruang terbuka, serta hubungan antar ruang (“linkage”). Metode pengumpulan data dilakukan melalui observasi, pengamatan foto udara, dan wawancara; sedangkan metode analisis melalui deskripsi secara kualitatif yang berupa “superimposed method” dari dua lapisan kondisi lahan, yakni kondisi tata ruang sebelum dan sesudah pembangunan jalan layang. Hasil penelitian menunjukkan bahwa pengaruh pembangunan Jalan Layang Janti terdapat pada massa bangunan (“solid”), pertambahan ruang terbuka yang berupa jaringan jalan, parkir, dan taman; sedangkan pada hubungan antar ruang ̶ secara visual dan struktural ̶ yakni tumbuhnya bangunan dengan bentuk dan gaya baru, sehingga bentuk tampilan bangunan secara keseluruhan tidak proporsional. Pada hubungan kolektif, Jalan Janti semakin kuat perannya sebagai kerangka utama jaringan jalan.Kata kunci : Pembangunan jalan layang, tata ruang, Kawasan Janti

A REVIEW ON THE BENEFITS OF HORTICULTURAL THERAPY FOR RETIREMENT COMMUNITY IN MALAYSIA

2017 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Amirul Amin Ismail ◽  
Ismail Samsuddin ◽  
Azman Zainonabidin ◽  
Harlina Mohd Ali
Keyword(s):  
Well Being ◽  
The Elderly ◽  
Retirement Community ◽  
Analysis Method ◽  
Horticultural Therapy ◽  
Seamless Integration ◽  
Ageing Society ◽  
After Effects ◽  
Malaysian Population ◽  
The Impact

By the year 2030, Malaysian population will experience the after effects of the rapid growth of ageing society. This paper investigates the impact of seamless integration of horticultural activity in the new residential typology of retirement community. It is believed that horticultural therapy is not only beneficial for physical and psychological but also promotes socialisation opportunities among the elderly. Comparative analysis method on selected precedent studies has been carried out and analysed in accordance with Malaysian context. Initial findings indicate that a retirement community with horticultural activity gives therapy for healthier well-being. This therapeutic activity can be apositive change in elderly lifestyle and essential towards the establishment of retirement community in Malaysia. 

Sign in / Sign up

Export Citation Format

Share Document