Laboratory and in situ investigation of the compressive strength of CFRD concrete

, Article Construction and Building Materials ; Volume 242 , 2020 Vatani Oskouei, A ; Nazari, R ; Houshmand Khaneghahi, M ; Sharif University of Technology

Elsevier Ltd 2020

Abstract

One of the most essential and costly stages in Concrete Face Rockfill Dams (CFRD) construction is to implement the concrete at the upstream face of the dam without joints. As the face concrete is considered as the most integral part to prevent water penetration in CFRDs, it's quality control is of paramount importance. One of the conventional approaches for quality control of the concrete which is used in CFRD is the compressive strength of laboratory samples. The comparison of laboratory and in situ measurements provides information about the accuracy of the obtained results. This research investigates the correlation of concrete compressive strength determined by using different methods in...

Seismic Reliability and Global Sensitivity Analysis of Concrete Gravity Dams

, M.Sc. Thesis Sharif University of Technology Houshmand Khaneghahi, Mohammad (Author) ; Ghaemian, Mohsen (Supervisor) ; Toufigh, Vahab (Supervisor)

Abstract

This research investigated the seismic performance of gravity dam in the reliability and sensitivity analysis framework under earthquake loading. The performance criteria were defined using crest displacement and tensile stress. The uncertainty due to the material properties of the dam was considered for the reliability approach, in addition to the different ground motion intensity levels for parametric analysis. The exceedance probability of the limit-state functions was computed for varying threshold values through Mean-Value Second-Moment, First-Order Reliability Method and improved Latin Hypercube sampling. Approximation methods were applied along with the sampling method for considering...

The effect of elevated temperatures on the tensile performance of GFRP and CFRP sheets

, Article Construction and Building Materials ; Volume 190 , 2018 , Pages 38-52 ; 09500618 (ISSN) Jarrah, M ; Pournamazian Najafabadi, E ; Houshmand Khaneghahi, M ; Vatani Oskouei, A ; Sharif University of Technology

Elsevier Ltd 2018

Abstract

In this study, the effects of fiber type (i.e., carbon and glass fibers) and intumescent paint on the tensile performance of fiber reinforced polymer (FRP) sheets at elevated temperatures are investigated. For this purpose, a series of tensile tests were conducted on the glass and carbon fiber reinforced polymer (GFRP and CFRP) sheets, with and without intumescent fire retardant paint, at different elevated temperatures. The studied temperatures ranged from 25 °C to 600 °C. Scanning electron microscopy was also used to examine the effects of elevated temperatures on FRP sheets and the fire protecting mechanism of the intumescent paint. Based on the test results, the tensile strength of the...

Effect of intumescent paint coating on mechanical properties of FRP bars at elevated temperature

, Article Polymer Testing ; Volume 71 , 2018 , Pages 72-86 ; 01429418 (ISSN) Houshmand Khaneghahi, M ; Pournamazian Najafabadi, E ; Shoaei, P ; Vatani Oskouei, A ; Sharif University of Technology

2018

Abstract

This paper investigates the influence of intumescent paint on the performance of FRP bars subjected to low (25–450 °C) and severe (450–800 °C) elevated temperatures. In this research, glass and carbon FRP bars with epoxy resin and coated with nitrogen-based intumescent paint were used. In addition to the temperature effects, a variety of FRP bar diameters were employed to determine its effect on the tensile behavior of FRP bars in the presence of intumescent paint. Further, Bayesian regression methods and ANOVA (ANalysis Of VAriance) were applied on the results to develop a predictive model form and quantify the contribution of the variables in the tensile performance of FRP bars,...

Production Planning and Configuration Selection in a Reconfigurable Manufacturing System (RMS) Considering Raw Materials

, M.Sc. Thesis Sharif University of Technology Keshavarz Mohammadian, Mohammad Reza (Author) ; Houshmand, Mahmoud (Supervisor)

Abstract

The Reconfigurable manufacturing system (RMS) was first introduced in 1996 with the ability to respond quickly to market changes and in response to global competition between companies. The effort of this research is to expand the problem presented in the Moghaddam et al. (2019) by introducing the concept of raw materials for the production of parts and related issues such as purchasing and warehousing raw materials, and providing a suitable solution to the problem. In the basic article, the RMS should utilize the best combination of machines and their configurations in proportion to the demand of the products in order to minimize the cost and produce all the demand. In this study, a large...

Development and Improvement of Failure Modes and Effects Analysis under Uncertainty (Fuzzy- epistemic) for Maintenance Planning

, M.Sc. Thesis Sharif University of Technology Seiti, Hamid Reza (Author) ; Houshmand, Mahmoud (Supervisor) ; Imani, Din Mohammad (Co-Advisor)

Abstract

Most of designers, manufacturers and all of the agents involved in product development processes are using the failure modes and effects analysis to reduce the potential failure of new products. Risk priority number (RPN) is calculated by multiplying occurrences (O), severity (S) and detection (D). This value is used as FMEA performance measure. Although the value of the RPN gives a good sight to product design and development, but firstly it ignores relative importance of the risk factors, secondly it is difficult to calculate the RPN value where there is shortage of product failure records and thirdly it is difficult to express risk factors with crisp values. In the above conditions FMEA...

Scar Segmentation in CMR Images without Using Contrast Agent

, M.Sc. Thesis Sharif University of Technology Badali Golezani, Elaheh (Author) ; Rohban, Mohammad Hossein (Supervisor) ; Houshmand, Golnaz (Co-Supervisor)

Abstract

Correct diagnosis of myocardial scar has always been a major challenge due to the low resolution of cardiac magnetic resonance imaging. The use of a gadolinium-based contrast agent that reveals a scar is the solution proposed in medical science. However, there are limitations to the use of contrast agents in some patients. In recent years, studies based on deep learning techniques have been presented, trying to identify myocardial infarction with the help of images without using contrast agent. This type of diagnosis can be done with the help of different movements of healthy and damaged tissue. Due to the lack of datasets suitable for this application, in this study, real dataset were...

Improve the classification and sales management of products using multi-relational data mining

, Article 2011 IEEE 3rd International Conference on Communication Software and Networks, ICCSN 2011, Xi'an, 27 May 2011 through 29 May 2011 ; 2011 , Pages 329-337 ; 9781612844855 (ISBN) Houshmand, M ; Alishahi, M ; Sharif University of Technology

2011

Abstract

There are some elements such as competition among companies and changes in demands which result in changes of customers' behaviors. Therefore, paying no attention to these changes may lead to a reduction in company benefits and loss of customers. Since data and their analyses determine the activities and decision makings of companies, data quality is of paramount in analyzing them because misinformation leads to wrong decision making. Since data mining has been designed to find out multi repetition patterns, it can be used to improve the product sales violations by sales people and increase the quality of data. Most of data mining models available try to find patterns in one table, but the...

An extended model of design process of lean production systems by means of process variables

, Article Robotics and Computer-Integrated Manufacturing ; Volume 22, Issue 1 , 2006 , Pages 1-16 ; 07365845 (ISSN) Houshmand, M ; Jamshidnezhad, B ; Sharif University of Technology

2006

Abstract

In this paper, we present an axiomatic modeling of lean production system design, using process variables (PVs). So far, we had developed a model for conceptual design of lean production systems by means of FR-DP relationships, the key characteristics of axiomatic design (AD) methodology, appeared in the proceedings of Second International Conference of Axiomatic Design. Albeit the model in question was thorough enough to be applied in various cases, its embedded abstract principles hamper straightforward applications and the required resources, tools, and techniques are not clarified. In AD terms, it lacks PVs created by mapping the design parameters (DPs) to the process domain to clarify...

A lean manufacturing roadmap for an automotive body assembly line within axiomatic design framework

, Article International Journal of Engineering, Transactions A: Basics ; Volume 17, Issue 1 , 2004 , Pages 51-72 ; 17281431 (ISSN) Houshmand, M ; Jamshidnezhad, B ; Sharif University of Technology

National Research Center of Medical Sciences 2004

Abstract

In this paper we are to present a practical application of Axiomatic Design (AD) methodology, as a roadmap to lean production, in redesigning a car body assembly line. Axiomatic Design theory provides a framework to simplify the whole problem. According to the AD principles, a hierarchical structure has been developed. The developed structure originated in lean manufacturing principles and existing conditions of an assembly line, revealed that elimination of all kinds of waste is a prerequisite for other functional requirements. Several main sources of waste were recognized in the assembly line and some practical solutions are suggested to alleviate these problems. In the initial survey, it...

Evaluating the Leanness and Agility Indexes of S.G.S Co

, M.Sc. Thesis Sharif University of Technology Lotfi, Maryam (Author) ; Houshmand, Mahmoud (Supervisor)

Abstract

In this research ,lean and agile indexes in S.G.S Co. are evaluated. This company is the first company in engineering and supplying automotive parts as well as the first supply chain management and organization of Saipa Group. In the part of evaluating the lean management level it is the developed model of the suggested approach by Jackson “implementing a lean management system” (Jackson, 1996). As S.G.S is engaged in servicing activities not in production, we have changed some factors in Jackson's methodology. Different with the last model, we got the results and used AHP method for getting the level in each key. Finally by using another AHP the lean index of the S.G.S Co. was identified....

A Novel Framework to Enable STEP-NC Extension of Tool Library Based on Cloud Manufacturing Paradigm

, M.Sc. Thesis Sharif University of Technology Alavian, Pooya (Author) ; Houshmand, Mahmoud (Supervisor)

Abstract

ISO 10303 Standard also known as STEP, is an standard in the domain of mechanical manufacturing that describes data relating to drawings, design, machining, process planning, engineering and other aspects of product which all together can describe the entire life cycle of products. However, as this standard is newly born and developing these data models are expensive and time consuming, so far, no data model for description of cutting tools is developed. In this project we study the STEP parts and protocols to understand how data is stored. We study EXPRESS Modeling language, the language developed as part of the STEP standard which is the official language of data modeling in STEP. And use...

A Novel System to Enable Interoperability Among Distributed CAM Software Packages and CNC Machining Post Processors

, M.Sc. Thesis Sharif University of Technology Hosseini, Ali (Author) ; Houshmand, Mahmoud (Supervisor)

Abstract

Today’s businesses strategies are changing from traditional point of view to globalization and distributed enterprise. Companies have to consider flexibility in term of quantity and variety. They have to manage and organize the product development chain where low cost resources are available. Therefore, enterprises and companies should facilitate the flow of information and increase the interoperability between distributed agents. The main information flow occurs in CAD/CAM/CNC chain. Information flow at the end of the chain has always been the main obstacle to enable interoperability. Old Standards for programming CNC machine tools are the main problem to exchange data and facilitate...

Integrated Process Planning System for Prismatic Parts Based on STEP

, M.Sc. Thesis Sharif University of Technology Foroozmand, Hamzeh (Author) ; Houshmand, Mahmoud (Supervisor)

Abstract

Nowadays, as a result of rapid changes of market, it is necessary to reduce the period between design and manufacturing of a new product. Among them, process planning is one of the most difficult elements of production chain and also, there are a few numbers of experts in this field. In addition, this process is time-consuming and costly. So, it is important for companies to reduce the period of new product’s presentation by reduction of process planning duration. On the other hand, it is proved that the lowest level of integration in CIM systems is in CAPP section. Integration provides sharing data in the system, so the other parts of production systems can exchange product information and...

A Cloud Based Architecture Design for Global Supply Chain

, M.Sc. Thesis Sharif University of Technology Darabi, Zahra (Author) ; Houshmand, Mahmoud (Supervisor)

Abstract

Supply chain as one of the most important and critical parts of the production process; could have significant effect on efficiency and productivity of the firms.Integration of supply chain (components from upstream to downstream of production system) has been recently noticed and considered remarkably since it could have a considerable impact on functional variables in supply chain systems such as: cost reduction, responsiveness, service level and decision making process. On the one hand, in the last decade, new trends in global economics and the ongoing pattern in multinationals to outsource their manufacturing process have made the integration process challenging and difficult. On the...

An Estimation Model for Computation and Control of Trajectory Coverage Error in Additive Manufacturing

, M.Sc. Thesis Sharif University of Technology Zargar, Farinaz (Author) ; Houshmand, Mahmood (Supervisor)

Abstract

During 1980s Additive Manufacturing technologies for the purpose of prototyping with fast and less expensive, under the name of Rapid Prototyping was invented. But nowadays under the vast progress made in this field, it possesses a notable place in different industries such as automobile manufacturing, aerospace, architecture, medicine and so on for part manufacturing. In all AM machines, the CAD model design part is manufactured by adding layered to each other. In this research, at first by explaining manufacturing process and current different technologies, the place of this manufacturing process in today and future industry, is analyzed. For discussing replacement of this method instead...

Order Production Planning, and Meeting Due-Dates for MTO Reconfigurable Manufacturing Systems

, M.Sc. Thesis Sharif University of Technology Asadi, Atefeh (Author) ; Houshmand, Mahmoud (Supervisor)

Abstract

Time based competition is considered as an importance strategy in the contemporary manufacturing systems. Reconfigurable Manufacturing System (RMS) is a new paradigm that not only produces the products with high productivity but also allows for rapid response to market changes. Despite the large impact on company performance, the importance of due date setting and order planning processes and related decisions is underexposed in the literature of RMS. The most important contribution of this thesis is orders planning under setting due date in make-to-order RMS environment. This thesis seeks to determine the best selection of several orders, their sequencing and corresponding configurations...

Design, Fabrication, and Experimental Study of a Flexible Cardiac Stabilizer for Beating Heart Robotic Surgery

, M.Sc. Thesis Sharif University of Technology Houshmand, Arvin (Author) ; Farahmand, Farzam (Supervisor)

Abstract

A popular way for performing minimally invasive heart surgery is to use cardiac stabilizers that fix the heart during surgery. In the recent years several research works have been conducted to develop effective cardiac stabilizers. While these developments have attempted to improve fixation of the heart, there are reports indicating that a rigid cardiac stabilization may induce injury to heart muscle tissues due to restricting the heart motion in all directions. A more efficient approach than rigid cardiac stabilization might be to use a flexible cardiac stabilizer in combination with a surgical robot having motion compensation capability. The scope of this research is designing a device to...

Collaborative Design and Manufacturing - a Platform for Collaborative Management of Product Development Using Cloud Computing Infrastructure within Small and Medium-Sized Enterprises

, M.Sc. Thesis Sharif University of Technology Akbar, Fatemeh (Author) ; Houshmand, Mahmoud (Supervisor)

Abstract

This study reviews the platforms developed in the context of collaborative product design by using cloud computing infrastructures in the field of small and medium-sized enterprises (SMEs), and proposes some criteria to evaluate these platforms. Considering the limitations of these platforms, a network has been designed for collaboration between the engineering, procurement, and construction companies as well as the employers. In this network, by registering a project by the employer, the bidding process begins. The member firms in the network, by controlling the timing and through a proper allocation of labour forces, propose their preliminary designs as well as their bid prices to the...

Application of Knowledge-based Systems (kbs) in Exchange and Integration Manufacturing Systems Information with Cloud Manufacturing Approach (In Case Cooling Tower)

, M.Sc. Thesis Sharif University of Technology Ghayazi, Abdolhossein (Author) ; Houshmand, Mahmoud (Supervisor)

Abstract

Product knowledge is the most precious asset of any manufacturing company, particularly for OKP companies. High level of customization is one characteristic of OKP which means more customer involvements in OKPPD activities, and customer requirements and expectations may be changing at any activity in PD, e.g., at designing stage. As SMEs, OKP companies always have limitation in resources such as machines tools, human resources, cutters, clamps, so managing the limitations is one of the major challenges that must be faced for maximizing the efficiently and productivity. The part of design that involves fuzzy problems and a lot of product knowledge, it is a critical part for the entire PD. In...