Homogenized modeling and micromechanics analysis of thin-walled lattice plate structures for brake discs

2018 ◽  
Vol 22 (2) ◽  
pp. 423-460 ◽  
Author(s):  
Aminreza Karamoozian ◽  
Chin An Tan ◽  
Liangmo Wang
Keyword(s):  
Strength Properties ◽  
Orthotropic Materials ◽  
Brake Disc ◽  
Disk System ◽  
Core Elements ◽  
The Face ◽  
Parent Alloy ◽  
Considerable Impact ◽  
Lattice Core ◽  
Type Lattice

Periodic cellular structures, especially lattice designs, have potential to improve the cooling performance of brake disk system. In this paper, the method of two scales asymptotic homogenization was used to indicate the effective elastic stiffnesses of lattice plates structures. The arbitrary topology of lattice core cells connected to the back and front plates which are made of generally orthotropic materials, due to use in brake disc design. This starts with the derivation of general shell model with consideration of the set of unit cell problems and then making use of the model to determine the analytical equations and calculate the effective elastic properties of lattice plate concerning the connected back and front plates. The analytical and numerical method allows determining the stiffness properties and the internal forces in the trusses and plates of the lattice. Three types of core-based lattice plates, which are pyramidal, X-type and I-type lattices, have been studied. The I-type lattice is characterized here for the first time with particular attention on the role that the cell trusses and plates plays on the stiffness and strength properties. The lattice designs are finite element characterized and compared with the numerical and experimentally validated pyramidal and X-type lattices under identical conditions. The I-type lattice provides 4% higher strength more than the other lattice types with 9% higher truss fraction coefficient. Results show that the stiffness and yield strength of the lattices depend upon the stress–strain response of the parent alloy of trusses and plates, the truss mass fraction coefficient, the face carriers thickness and the core elements parameters. The study described here is limited to a linear analysis of lattice properties. Geometric nonlinearities, however, have a considerable impact on the effective behavior of a lattice and will be the subject of future studies.

scholarly journals Surgical anatomy in the age of EWTD and ISCP

2008 ◽  
Vol 90 (7) ◽  
pp. 245-245
Author(s):  
Vishy Mahadevan
Keyword(s):  
Surgical Training ◽  
Surgical Anatomy ◽  
Working Time ◽  
European Working Time Directive ◽  
Medical Careers ◽  
European Working ◽  
The Face ◽  
Considerable Impact ◽  
The Uk ◽  
Working Time Directive

Four major new initiatives being implemented nationally are set to have a considerable impact on the nature of surgical training in the UK. When fully operational, these developments will alter the face of surgical training: the European Working Time Directive (EWTD), Modernising Medical Careers (MMC), the Intercollegiate Surgical Curriculum Programme (ISCP) and the new MRCS examination.

The Dynamics Simulation of Braking Process on Automobile Disc Brake

2010 ◽  
Vol 139-141 ◽  
pp. 2658-2661 ◽  
Author(s):  
Chuan Qi Fu ◽  
Zhou Wang ◽  
Bin Li ◽  
Chi Yu
Keyword(s):  
Initial Velocity ◽  
Dynamics Simulation ◽  
Brake Disc ◽  
Disc Brake ◽  
Stress Concentrations ◽  
Contact Algorithm ◽  
The Face ◽  
Improvement Measures ◽  
Braking Process ◽  
Dynamics Simulations

For a certain type of automobile disc brakes, brake discs and friction linings were modeled by Pro/E. The dynamics simulations of braking process on disc brake were performed by the frictional contact algorithm and nonlinear finite element method. Distribution of stress, strain and displacement on the brake parts were investigated with different initial velocity. Analysis results shown that redistributions of stress and strain had occurred on the face of brake disc and friction linings in braking process. Meanwhile, the increased initial velocity resulted in increased stress and stain. Besides the stress concentrations appeared in brake disc role and friction lining corners at the beginning of braking, however, stress and stain became uniform along the braking. Analysis results provided the research of the optimum design and testing of disc brake with theoretic gist. And some improvement measures to the structure of disc brake were proposed.

scholarly journals Investigating the Effect of Blended Learning on Iranian EFL Learners' Autonomy, Self-esteem, and Vocabulary Achievement

2021 ◽  
Vol 4 (6) ◽  
pp. 155-162
Author(s):  
Parisa Aalinezhad ◽  
Zohreh Salehan ◽  
Zohreh Noroozi
Keyword(s):  
Blended Learning ◽  
Learner Autonomy ◽  
Self Esteem ◽  
Control Group ◽  
Efl Learners ◽  
English As Foreign Language ◽  
Post Test ◽  
The Face ◽  
Considerable Impact ◽  
Vocabulary Achievement

This study aimed at examining the influence of blended learning on Iranian English as Foreign Language (EFL) learners' autonomy, self-esteem, and vocabulary achievement. To do this, 60 Iranian females intermediate EFL learners were chosen from an institute in Ilam, Iran. Then, the selected participants were divided into two groups; one experimental group (EG) and one control group (CG). Each group contained 30 learners. Afterwards, in three separate sessions, the instruments of learner autonomy, self-esteem, and vocabulary progress were distributed and administered among the participants of both groups. The researchers offered a blended learning teaching framework to the EG to encourage students to utilize the language in and out of the classroom. The target vocabulary was learnt by the learners using blended learning techniques. While the same vocabularies were learned through the face-to-face way of instruction in the CG. After the period of teaching that lasted for 6-weeks, the participants of both groups received the learner autonomy, self-esteem, and vocabulary achievement instruments as post-test. The results demonstrated that instruction through a blended learning approach had a considerable impact on participants' level of autonomy and vocabulary achievement. But the approach had no significant impact on learners' self-esteem. EFL learners, Teachers, and material developers can benefit from the results of the study.

Bamboo Composite panel as furniture component using bamboo mat and planer shavings

2015 ◽  
Vol 22 (2) ◽  
pp. 103-106
Author(s):  
Khurshid Akhter ◽  
Md. Rahaman ◽  
Mozammel Chowdhury ◽  
Md. Islam
Keyword(s):  
Boric Acid ◽  
Strength Properties ◽  
Modulus Of Rupture ◽  
Composite Panel ◽  
Particle Board ◽  
Bambusa Balcooa ◽  
Bending Modulus ◽  
Bambusa Vulgaris ◽  
The Face ◽  
Bambusa Tulda

Bamboo in panel form is well suited to wood substitute can be used as furniture components. During the preparation of strips by four side planer huge amount of wastage are obtained. In the present study, Planer shavings of Bhyjja, (Bambusa vulgaris) and Borak, (Bambusa balcooa) bamboo are used for manufacturing particleboard and mat overlaid particleboard. Mitinga, (Bambusa tulda) bamboo is used for making mat. Borax-boric acid (BB) treatments were given to enhance the durability of mat. The treatment were carried out using borax-boric acid (1:1) aqueous solution of different concentrations at different time schedule by soaking process.. Retention 22.11 kg/m3 to 27.41 kg/m3 were obtained when the mat were treated with 5% and 7% BB solution for 1 to 3 days. The modulus of rupture of bamboo particle board and mat overlaid particleboard were found 16 N/ mm2 and 25 N/ mm2respectively using planer shavings of Bambusa balcooa. The modulus of rupture of bamboo particle board and mat overlaid particleboard were found 18 N/ mm2 and 26.5 N/ mm2 respectively using planer shavings of Bambusa vulgaris. It was observed that the strength properties of board made form B. vulgaris higher than that of B. balcooa . Static bending /modulus of rupture of the particleboard are satisfactory. Modulus of rupture and tensile strengths of all the boards, however, satisfy the Indian and British standards. The strength properties of the mat overlaid particle board were increased due to the use of bamboo mat in the face and back position.

Land and Reparation Politics and Policy after Apartheid

2020 ◽  
Author(s):  
Thuto Thipe
Keyword(s):  
South Africa ◽  
Land Tenure ◽  
The State ◽  
Tenure Security ◽  
Administration System ◽  
Core Elements ◽  
The Face ◽  
Communal Areas ◽  
The Right ◽  
Land Restitution

Two successive 2018 court judgments guaranteed people living in the parts of South Africa demarcated as communal areas the right to refuse to allow mining on their land. As debates around land restitution and redistribution gripped the country, these cases shone a light on land tenure security in people’s struggles to remain on their ancestral land in the face of continued dispossession after 1994. This article argues that in preserving core elements of the colonially created tribal administration system in the democratic landscape, the state has retained the structures and the imaginative framework that allow particular people to be treated as “natives” who can be moved and stripped of foundational rights, as tribal institutions were designed to do. The Maledu and Baleni cases are illustrative of struggles across the country in which people in communal areas are demanding full recognition and exercise of their rights as citizens.

Methodology for multiscale design and optimization of lattice core sandwich structures for lightweight hopper railcars

2020 ◽  
Vol 234 (21) ◽  
pp. 4224-4238 ◽  
Author(s):  
Danial Molavitabrizi ◽  
Jeremy Laliberte
Keyword(s):  
Sandwich Structure ◽  
Sandwich Panel ◽  
Failure Modes ◽  
Minimum Weight ◽  
Strength Properties ◽  
Optimized Design ◽  
Design And Optimization ◽  
Floor Panel ◽  
Octet Truss ◽  
Lattice Core

This research is focused on developing new lightweight structures for railcars based on a pre-selected material, i.e. Al 2099. The goal is to design a new sandwich structure with an octet truss lattice core for a floor panel of a hopper freight railcar designed to meet North American standards. For that, mesoscale to macroscale design of the sandwich panel was performed. In mesoscale design, relative density, elastic properties, strength properties, and failure criterion of the lattice unit cell were investigated. In the next step, these properties were used as inputs for macroscale design, i.e. design of the whole sandwich structure. Multiple failure modes associated with the lateral loading of a sandwich panel were analyzed. These equations in conjunction with the minimum weight target led to an optimization problem, and the minimum required thicknesses were obtained. Finally, the new optimized design was validated by comparing different finite element simulations with the exact analytical equations. By using this type of structure, a 53% weight reduction was achieved on the floor panel which ultimately led to an estimated 12.5% reduction in the weight of the whole freight railcar body.

The Importance of Xylan for the Strength Properties of Spruce Kraft Pulp Fibres

Holzforschung ◽  
2001 ◽  
Vol 55 (6) ◽  
pp. 639-644 ◽  
Author(s):  
C. Schönberg ◽  
T. Oksanen ◽  
A. Suurnäkki ◽  
H. Kettunen ◽  
J. Buchert
Keyword(s):  
Tensile Strength ◽  
Chemical Composition ◽  
Fracture Energy ◽  
Kraft Pulp ◽  
Fibre Length ◽  
Strength Properties ◽  
Total Charge ◽  
Pulp Fibres ◽  
Considerable Impact

Summary In this work the role of xylan in spruce kraft pulp fibres was investigated by selectively removing the pulp fibre xylan and also by sorbing xylan onto the pulp fibres. The effects of xylan removal and sorption on fibre properties were measured and the chemical composition of the fibres and also that of the selectively removed xylans was analyzed. According to the results the xylanase could act on both sorbed and native xylan located on accessible fibre surfaces. Xylan was found to affect the strength properties of handsheets. The location and the charge of xylan had a considerable impact on the formation of interfibre bonds. Scott Bond-values correlated with the amount of surface xylan on fibre surfaces, whereas tensile strength was affected by the total amount of xylan and particularly by the total charge of the fibres. The fracture energy was determined by the combined effect of interfibre bonding ability and effective fibre length.

scholarly journals Breaking Through Barriers and Building Disaster Mental Resilience: A Case Study in the Aftermath of the 2015 Nepal Earthquakes

2019 ◽  
Vol 16 (16) ◽  
pp. 2964 ◽  
Author(s):  
Alisha KC ◽  
Connie Cai Ru Gan ◽  
Febi Dwirahmadi
Keyword(s):  
Mental Health ◽  
Disaster Preparedness ◽  
Health Issues ◽  
Case Study Method ◽  
Present Context ◽  
The Face ◽  
Considerable Impact ◽  
Mental Resilience ◽  
The Government

Introduction: Nepal was hit by two devastating earthquakes in 2015 that disrupted its socio-economic system and shattered many lives, resulting in increased mental health issues during the post-earthquake phase. Disasters can have severe mental health impacts on the affected population, making it necessary to enhance resilience within communities and to help them to adapt well in the face of adversities. From these earthquakes, this study looks to identify measures needed to develop community mental resilience for disaster preparedness in Nepal. Method: We conducted this research using the qualitative case study method and thematic analysis (TA). Result: Several activities were carried out by organizations to support the psycho-social aspects of communities, but were challenged by existing barriers. After considering the present context, this study presents five recommendations for mental resilience and also suggests the utilization of existing resources, such as faith-based organizations and teachers in the communities. Despite the considerable impact, communities demonstrate their own resilience, to some extent, through the culture of sharing and helping each other. Conclusions: A firm commitment is required from the government to enhance resilience by mainstreaming mental health in all areas of disaster management and planning.

Sign in / Sign up

Export Citation Format

Share Document