Workplace based assessments: A complement to the quarter model

2013 ◽  
Vol 50 (3) ◽  
pp. 346-347
Author(s):  
Gaurav Atreja
Keyword(s):  
Quarter Model

scholarly journals Performance Analysis of a Semiactive Suspension System with Particle Swarm Optimization and Fuzzy Logic Control

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Abroon Jamal Qazi ◽  
Clarence W. de Silva ◽  
Afzal Khan ◽  
Muhammad Tahir Khan
Keyword(s):  
Fuzzy Logic ◽  
Particle Swarm Optimization ◽  
Fuzzy Logic Controller ◽  
Ride Comfort ◽  
Particle Swarm ◽  
Active Suspension ◽  
Suspension System ◽  
Swarm Optimization ◽  
Quarter Model ◽  
Semiactive Suspension

This paper uses a quarter model of an automobile having passive and semiactive suspension systems to develop a scheme for an optimal suspension controller. Semi-active suspension is preferred over passive and active suspensions with regard to optimum performance within the constraints of weight and operational cost. A fuzzy logic controller is incorporated into the semi-active suspension system. It is able to handle nonlinearities through the use of heuristic rules. Particle swarm optimization (PSO) is applied to determine the optimal gain parameters for the fuzzy logic controller, while maintaining within the normalized ranges of the controller inputs and output. The performance of resulting optimized system is compared with different systems that use various control algorithms, including a conventional passive system, choice options of feedback signals, and damping coefficient limits. Also, the optimized semi-active suspension system is evaluated for its performance in relation to variation in payload. Furthermore, the systems are compared with respect to the attributes of road handling and ride comfort. In all the simulation studies it is found that the optimized fuzzy logic controller surpasses the other types of control.

scholarly journals Analysis of the distribution of temperature fields in the braked railway wheel

2018 ◽  
Vol 157 ◽  
pp. 02048 ◽  
Author(s):  
Andrej Suchánek ◽  
Jozef Harušinec ◽  
Mária Loulová ◽  
Peter Strážovec
Keyword(s):  
Transient Analysis ◽  
Equivalent Stress ◽  
Temperature Fields ◽  
Railway Wheel ◽  
Speed Up ◽  
Quarter Model ◽  
Thermal Transient ◽  
Railway Wheels ◽  
Brake Block ◽  
Thermal Transient Analysis

The article deals with detection of reduced stress in a braked railway wheel, based on thermal transient analysis on virtual models, which influence the characteristics of the railway wheels. Structural analysis was performed by means of the ANSYS Multiphysics program system package. Thermal transient analysis deals with detection of temperature fields which are a result of braking by brake block. The applied heat flux represents the heat generated by friction of brake block. It is applied to a quarter model of the wheel to speed up the calculation. This analysis simulates two braking processes with subsequent cooling. Distribution of the equivalent stress was detected in the railway wheel cross section, at selected points. The input parameters were taken from the thermal transient analysis. These equivalent stresses result from thermal load.

Study of a quarter model HMMWV suspension system using a magnetorheological fluid damper

2003 ◽  
Author(s):  
Eyup S. Karakas ◽  
Faramarz Gordaninejad ◽  
Cahit A. Evrensel ◽  
Moon-Su Yeo ◽  
Yanming Liu
Keyword(s):  
Magnetorheological Fluid ◽  
Suspension System ◽  
Magnetorheological Fluid Damper ◽  
Fluid Damper ◽  
Quarter Model

scholarly journals Current and Future Potential Distribution Areas of Carphoborus minimus (Fabricius, 1798) in Turkey

2020 ◽  
Vol 68 (4) ◽  
pp. 141-148
Author(s):  
Ismail Şen ◽  
Oğuzhan Sarikaya ◽  
Ömer Kamil Örücü
Keyword(s):  
Potential Distribution ◽  
Distribution Area ◽  
Change Model ◽  
Result State ◽  
Change Analysis ◽  
Distribution Ranges ◽  
Quarter Model ◽  
Future Potential ◽  
Climate Change Model ◽  
Temperature Seasonality

Our study aims to model the current and future (2041-2060 and 2081-2100) distribution areas of Carphoborus minimus (Fabricius, 1798) according to SSP2 and SSP5 emission scenarios. Current and future potential distribution areas of the species were predicted using the maximum entropy (MaxEnt) method and the MIROC6 climate change model. Finally, change analysis was performed to reveal the distributional changes between the present and future distribution ranges of the species. Our study has made it clear that the most impactful bioclimatic factors on the distribution of the species are temperature seasonality, isothermality, and precipitation of the driest quarter. Model results showed that the suitable distribution range for C. minimus is western and southern Anatolia. Models presented that the species will expand its distribution area through northern Anatolia in the 2050s and 2090s due to the changing ecological environment. In addition to that, the results of the change analysis showed that suitable distribution areas for the species will increase between 7% and 13.5% with time. Therefore, the species can become a new threat to the forests of Northern Anatolia. As a result, state forestry authorities should take precautions against this bark beetle species in the pine stands of northern Turkey in the future. Moreover, land-use plans should be developed to prevent the degradation of forest areas and to plan suitable trees for afforestation.

scholarly journals Kerapatan Mangrove dan Konservasinya di Bacan Kabupaten Halmahera Selatan Provinsi Maluku Utara

2018 ◽  
Vol 6 (02) ◽  
pp. 25
Author(s):  
Abdulrasyid Tolangara ◽  
Hasna Ahmad
Keyword(s):  
Research Result ◽  
Observation Data ◽  
Natural Area ◽  
Community Based ◽  
Transect Line ◽  
Conservation Effort ◽  
Quarter Model ◽  
The Government ◽  
Quantitative Descriptive ◽  
Model Point

AbstrakHutan mangrove merupakan perpaduan antara dua habitat yaitu terrestrial dan aquatik. Dalam perkembangannya ekosistem ini selalu mengalami kerusakan, ini terjadi kerena belum ada perhatian pemerintah untuk mencegahnya. Metode penelitian ini adalah deskriptif kuantitatif, dengan  menggunakan model Point Centered Quarter dan pengambilan sampel dengan menggunakan garis transek serta plot hitung berukuran 10mx10m untuk pengamatan tingkat pohon. Mangrove yang diukur pada 2 kawasan yaitu kawasan mangrove alami (A) yang teridiri empat stasiun dan kawasan mangrove rehabilitasi (B) juga terdapat empat stasiun. Pohon yang dipilih adalah pohon yang paling dekat di setiap quarter. Data pengamatan kemudian dianalisis secara kuantitatif  berupa kerapatan jenis mangrove di setiap stasiun. Hasil penelitian menunjukkan bahwa kerapatan jenis mangrove  kawasan alami berada pada kategori jarang misalnya stasiun I pada jenis A. alba 512 individu/m2, stasiun II terdapat pada jenis S. alba  456 individu/m2 dan stasiun III pada jenis R. apiculata 326 individu/m2. Sedangkan pada kawasan rehabilitasi berada pada kategori padat hingga sedang, misalnya pada stasiun IV kategori padat yaitu jenis B. gymnorrhiza 3.400 individu/m2, stasiun I kategori padat jenis R. apiculata 2.100 individu/m2, dan stasiun II kategori padat  terdapat pada jenis jenis R. stylosa dan stasiun III kategori sedang terdapat pada jenis R. mucronata 1.324 individu/m2. Ini terjadi akibat aktifitas masyarakat yang selalu memanfaatkan potensi hutan tersebut, tanpa upaya konservasi, maka diperlukan upaya konservasi dengan model pengelolaan yang berbasis masyarakat (Community Based Management).Kata Kunci: Mangrove, Kerapatan, Konservasi, Bacan. AbstractMangrove forest is a combination of two habitats, terrestrial and aquatic. In its development, the ecosystem experiences damage due to the less attention from the government to prevent it. Therefore, information is needed to find out about the comparison of density between natural and rehabilitation areas. The research method used was quantitative descriptive using Point Centered Quarter model and sampling used was transect line with calculation plot in size of 10mx10m for observation of tree stage. Mangrove was measured in two areas, natural mangrove (A) and rehabilitation mangrove (B) both consisted of four stations. Trees chosen were the closest trees in each quarter. Observation data was analyzed quantitatively in form of the density of mangrove type in each station. The research result indicates that the density of mangrove type in natural area was in sparse category, such as in Station I for type of A. Alba the density was 512 individual/m2, Station II with type of S. alba was 456 individual/m2 and Station III in type of R. apiculata was 326 individual/m2. In rehabilitation area, on the other hand, was in dense to moderate category, such as the dense category in Station IV was for type of B. gymnorrhiza of 3,400 individual/m2, Station I was for type of R. apiculata of 2,100 individual/m2, and Station II was for R. stylosa. Whereas, for moderate category in Station III was in R. mucronata of 1,324 individual/m2. It was due to the activity of the community that utilized the forest potential without conservation effort. Therefore, a conservation effort is needed through community based management model.Keywords: Mangrove, Density, Conservation, Bacan

Modeling Simplification for Thermal Mechanical Analysis of High Density Chip-to-Substrate Connections

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Ping Nicole An ◽  
Paul A. Kohl
Keyword(s):  
Boundary Conditions ◽  
Flip Chip ◽  
Plane Deformation ◽  
Three Dimensional ◽  
Symmetry Plane ◽  
Mechanical Analysis ◽  
Displacement Error ◽  
Quarter Model ◽  
Thermal Mechanical Analysis ◽  
Time Chip

Finite element modeling (FEM) is an important component in the design of reliable chip-to-substrate connections. However, FEM can quickly become complex as the number of input/output connections increases. Three-dimensional (3D) chip-substrate models are usually simplified where only portions of the chip-substrate structure is considered in order to conserve computer resources and time. Chip symmetry is often used to simplify the models from full-chip structures to quarter or octant models. Recently, an even simpler 3D model, general plane deformation (GPD) slice model, has been used to characterize the properties of the full-chip and local regions on the structures, such as in the structures for solder ball fatigue. In this study, the accuracy of the GPD model is examined by comparing the mechanical behavior of a flip-chip, copper pillar package from various full and partial chip models to that of the GDP model. In addition, it is shown that the GPD model can be further simplified to a half-GPD model by using the symmetry plane in the middle of the slice and choosing the proper boundary conditions. The number of nodes required for each model and the accuracy of the different FEM models are compared. Analysis of the maximum stress in the silicon chip shows that the full-chip model, quarter model, and octant model all convergence to the same result. However, the GPD and half-GPD models, with the previously used boundary conditions, converge to a different stress values from that of the full-chip models. The error in the GPD models for small, 36 I/O package was 4.7% compared to the more complete, full-chip FEM models. The displacement error in the GPD models was more than 50%, compared to the full-chip models, and increased with larger structures. The high displacement error of the GPD models was due to the ordinarily used boundary conditions which neglect the effect from adjacent I/O on the sidewall of the GPD slice. An optimization equation is proposed to account for the spatial variation in the stress on the GPD sidewall. The GPD displacement error was reduced from 50% to 3.3% for the 36 pillar array.

scholarly journals Calculating of stress intensity factors of soldered joints with multiple cracks

2019 ◽  
Vol 14 (1) ◽  
pp. 284
Author(s):  
Al Emran Ismail ◽  
Saifulnizan Jamian ◽  
Kamarul Azhar Kamarudin ◽  
Mohd Khir Mohd Nor ◽  
Mohd Norihan Ibrahim ◽  
...  
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Multiple Cracks ◽  
Tension Stress ◽  
Crack Interaction ◽  
Intensity Factors ◽  
Ansys Apdl ◽  
Two Factors ◽  
Quarter Model ◽  
Plain Strain

<span>This paper presents the solution of stress intensity factors of multiple cracks at the joint between two materials. Based on the literature survey, there are tremendous number of works found on the study of edge and central cracks. On the other hand, several papers on the multiple cracks can be also be found in open literature. However, the work on multiple cracks with different crack sizes are hard to find. Therefore, this paper focuses to study the crack interaction obtained from different crack sizes. ANSYS APDL is used to model and solve the problems considering the cracks embedded in the plain strain plate under tension stress. There are two important parameters are considered such crack sizes and mechanical mismatches between joint and based materials. Since the crack is symmetrical, only a quarter model is used and verified. Based on the numerical simulation, it is found that two factors are significantly affected the multiple cracks at the joints such as mechanical mismatches and relative crack sizes.</span>

scholarly journals Evaluation of different approaches to 3d numerical model development of the contact zone between elementary asperities and flat surface

2017 ◽  
Vol 4 (17) ◽  
pp. 40-53 ◽  
Author(s):  
Pawel MACIOLKA ◽  
Jerzy JEDRZEJEWSKI
Keyword(s):  
Contact Zone ◽  
Flat Surface ◽  
Model Development ◽  
Real Surface ◽  
Contact Loading ◽  
The Real ◽  
Subsurface Zone ◽  
Elastoplastic Properties ◽  
Quarter Model ◽  
Contact Characteristic

This paper presents two triaxial finite element (FE) models: a “full model” and a “quarter model”, representing the contact between the specimen’s rough surface and the ideally smooth and flat surface of the punch. Models have a contact zone that represents the topography of the real surface and has elastoplastic properties close to those of the real contact. The contact zone was entirely modelled on the basis of roughness measurements performed on a real milled specimen made of 5083 aluminium alloy. The development of the FE models, the stages in their refinement and the interlinking of the contact zone with the material of the specimen are described. The results of the computed deformations occurring during the specimen contact loading with the punch were compared with the experimental results. The possible causes of the observed deviations of the computer simulation results from the experimental ones were discussed. The models were used to analyse the effect of the specimen’s material properties, i.e. Young’s modulus, yield strength, compressive strength and material hardening, on the deformations in the contact. On this basis a procedure for predicting the parameters describing the contact characteristic in cases of changes in the properties of the subsurface zone is proposed

Sign in / Sign up

Export Citation Format

Share Document