The Study of Wooden Clamps for Strengthening of Connection on Bamboo Truss Structure

2015 ◽  
Vol 72 (5) ◽  
Author(s):  
Astuti Masdar ◽  
Bambang Suhendro ◽  
Suprapto Siswosukarto ◽  
Djoko Sulistyo
Keyword(s):  
Construction Projects ◽  
Lower Cost ◽  
High Strength ◽  
Truss Structure ◽  
Gusset Plates ◽  
Gusset Plate ◽  
Practical Applications ◽  
Lower Weight ◽  
Connection System ◽  
Plate System

High strength bamboo material cannot be fully utilized in construction projects due to the constraints of the connection system. The connection system element on the truss structure greatly affects the strength of the structure. Several studies have been completed to provide higher strength of the truss connections. However, the connection system is constrained by the costs of construction, availability of materials, equipment, skilled labored standardization. In this study, a connection system that possesses lightweight properties but with higher strength and lower cost while keeping the form of the bamboo being connected to remain natural has been developed. The proposed connection system consists of bolts, wooden gusset plates and special wooden clamps that have been adjusted with the shape and dimension of the bamboos being connected. A connection system without filler material on bamboo culms and wooden clamps used to increase the contribution to the shear at the connection has been proposed. The results showed an increase in the strength of the proposed connection of about 40% of the wood gusset plate system using wooden clamps than connection system without using wooden clamps, so it can be concluded that the proposed connection system possesses higher strength, yet much lower weight and has the potential for practical applications.

scholarly journals Parametric Investigation of Effect of Abnormal Process Conditions on Self-Piercing Riveting

2020 ◽  
Vol 10 (7) ◽  
pp. 2520 ◽  
Author(s):  
Taek-Eon Jeong ◽  
Dong-Hyuck Kam ◽  
Cheolhee Kim
Keyword(s):  
Process Parameters ◽  
Dissimilar Materials ◽  
High Strength ◽  
Process Conditions ◽  
Al Alloy ◽  
Main Process ◽  
Cross Sectional ◽  
Practical Applications ◽  
Parametric Investigation ◽  
Offset Distance

Self-piercing riveting (SPR) is one of the mechanical joining processes, and its application to Al/Fe dissimilar materials combination, which is hard to weld, is expanding in the automotive industry. The main process parameters in SPR are types of rivet and die, setting force, and rivet setting speed. Previously, the relationship between the main process parameters and output parameters such as cross-sectional characteristics and joint strength has been studied to optimize the SPR process. In practical applications, there are unexpected and abnormal process conditions such as poor fit-up, angular misalignment, edge offset distance, and inaccurate setting and pre-clamping forces, and their effects on the joining quality have not been discussed. In this study, parametric investigation was performed using an experimental design on SPR joints for 1 mm-thick high strength steel (590 DP) and 2 mm-thick Al alloy (Al5052-H32). The main effect of each level of the abnormal process parameters on the output parameters was statistically investigated, and the analysis of variance was performed for each abnormal process parameter. In the range of abnormal process conditions applied, the set force was the most significant factor affecting the output parameters, and the effect of pre-clamping force on the output parameters was the least significant.

The Optimization Design of Mechanical Structure Based on CAE Technology

2011 ◽  
Vol 130-134 ◽  
pp. 672-676 ◽  
Author(s):  
Gui Chuan Hu ◽  
Jing Hua Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Product Innovation ◽  
Optimization Design ◽  
Lower Cost ◽  
Truss Structure ◽  
Optimized Design ◽  
Light Weight ◽  
Important Sign ◽  
Cae Technology

The important sign of product innovation is the superior to exploit better manufacture functions, light weight as well as reliable performances with lower cost. The paper is focused on the truss structure optimized design which is used for arch bridge reinforcement. The strength, stiffness and dynamics consideration are analyzed by finite element method (FEM), and the topology optimized truss structure is put forward based on the analyzed results.

scholarly journals Cracking and Toughening Mechanisms in Nanoscale Metallic Multilayer Films: A Brief Review

2018 ◽  
Vol 8 (10) ◽  
pp. 1821 ◽  
Author(s):  
Qing Zhou ◽  
Yue Ren ◽  
Yin Du ◽  
Dongpeng Hua ◽  
Weichao Han
Keyword(s):  
Fracture Toughness ◽  
High Strength ◽  
Plastic Instability ◽  
Multilayer Films ◽  
Fracture Mechanisms ◽  
Toughening Mechanisms ◽  
Individual Layer ◽  
Practical Applications ◽  
Mechanical Responses ◽  
The Individual

Nanoscale metallic multilayer films (NMMFs) have captured scientific interests on their mechanical responses. Compared with the properties of monolithic films, multilayers possess unique high strength as the individual layer thickness reduces to the nanoscale, which is benefited from the plentiful hetero-interfaces. However, NMMFs always exhibit a low fracture toughness and ductility, which seriously hinders their practical applications. While there have been reviews on the strengthening and deformation mechanisms of microlaminate, rapid developments in nanotechnology have brought an urgent requirement for an overview focused on the cracking and toughening mechanisms in nanoscale metallic multilayers. This article provides an extensive review on the structure, standard methodology and fracture mechanisms of NMMFs. A number of issues about the crack-related properties of NMMFs have been displayed, such as fracture toughness, wear resistance, adhesion energy, and plastic instability. Taken together, it is hoped that this review will achieve the following two purposes: (1) introducing the size-dependent cracking and toughness performance in NMMFs; and (2) offer a better understanding of the role interfaces displayed in toughening mechanisms. Finally, we list a few questions we concerned, which may shed light on further development.

Use of Plastic Commercial Off-the-Shelf (COTS) Microcircuits for Space Applications

2003 ◽  
Author(s):  
R. David Gerke ◽  
Andrew A. Shapiro ◽  
Shri Agawal ◽  
David M. Peters ◽  
Michael A. Sandor
Keyword(s):  
Lower Cost ◽  
High Reliability ◽  
Space Applications ◽  
Active Devices ◽  
Lower Weight ◽  
Payload Mass ◽  
Commercial Off The Shelf ◽  
Time Required ◽  
The Cost ◽  
Package Materials

Commercial-off-the-shelf (COTS) plastic encapsulated microcircuits (PEM) are candidate-packaging technologies for spacecraft due to their enhanced performance, lower weight and lower cost. Much of the electronics used in space applications would be considered obsolete by everyday standards. This is primarily due the cost and time required for full space qualification. In order to gain the performance available in today’s electronics, COTS PEMs offer a viable path. PEMs can weigh half as much as their counter part ceramic packages. A lighter package results in a smaller overall payload for the same board functionality, a concern of critical importance for space missions because the payload mass dictates the launch vehicle requirements. Costs can be potentially reduced by using screening, accelerated testing or partial qualification techniques to complement the existing commercial qualification as well as by the reduced package materials costs. Assessing the risk associated with potentially lower reliability devices, engineers within the commercial and aerospace industries are using trade-off and risk analysis to aid in reducing spacecraft system cost while increasing performance and maintaining high reliability. In this paper we will outline the issues facing the use of COTS PEMs for spaceflight hardware from the aspect of both the electronic active devices as well as their packages. Finally, we will provide some guidelines for their use.

Weld Metal Hydrogen Cracking in Transmission Pipelines Construction

2010 ◽  
Author(s):  
Sheida Sarrafan ◽  
Farshid Malek Ghaini ◽  
Esmaeel Rahimi
Keyword(s):  
Weld Metal ◽  
Construction Projects ◽  
High Strength Steels ◽  
High Strength ◽  
Carbon Equivalent ◽  
Transverse Cracks ◽  
Diffusible Hydrogen ◽  
Hydrogen Cracking ◽  
Girth Welds ◽  
Welding Position

Developments of high strength steels for natural gas pipelines have been in the forefront of steelmaking and rolling technology in the past decades. However, parallel to such developments in steel industry, the welding technology especially with regards to SMAW process which is still widely used in many projects has not evolved accordingly. Decreasing carbon equivalent has shifted the tendency of hydrogen cracking from the HAZ to the weld metal. Hydrogen cracking due to its complex mechanism is affected by a range of interactive parameters. Experience and data gained from field welding of pipeline construction projects indicated that weld metal hydrogen cracking is related to welding position as it occurs more in the 6 o’clock position of pipeline girth welds. In this research an attempt is made to open up the above observation in order to investigate the contributory factors such as welding position and welding progression in terms of diffusible hydrogen and possibly residual stress considerations. It was observed that transverse cracks produced in laboratory condition may not be detected by radiography. But, the higher tendency for cracking at 6 o’clock position was confirmed through bend test. It is shown that more hydrogen can be absorbed by the weld metal in the overhead position. It is shown that welding progression may also have a significant effect on cracking susceptibility and it is proposed that to be due to the way that weld residual stresses are developed. The observations can have an important impact on planning for welding procedure approval regarding prevention of transverse cracking in pipeline girth welds.

Tension and shear block failure of bolted gusset plates

2006 ◽  
Vol 33 (4) ◽  
pp. 395-408 ◽  
Author(s):  
Bino B.S Huns ◽  
Gilbert Y Grondin ◽  
Robert G Driver
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Test Results ◽  
Limit States ◽  
Gusset Plates ◽  
Gusset Plate ◽  
Current Design ◽  
Shear Block ◽  
The Finite Element Model

Despite the large database of test results for tension and shear block failure in gusset plates, the exact progression of the failure mechanism is not clear. Although current design equations predict the capacity of gusset plates fairly well, it is important for a design equation to not only predict the capacity reliably but also reflect the failure mode accurately. Recent experimental and numerical research has indicated that current design equations do not always predict the failure behaviour accurately. A finite element model was therefore developed to predict the sequence of events that leads to the tear-out of a block of material from a bolted gusset plate in tension. The model was developed to provide a useful tool for studying tension and shear block failure in gusset plates and other structural elements. This paper presents the development of the finite element model and procedure for prediction of tension and shear block failure in gusset plates. Making use of the finite element model, the database of test results is also expanded to include gusset plates with a larger number of transverse lines of bolts than what has been obtained experimentally. A reliability analysis is used to assess several design equations, including the equation adopted in CAN/CSA-S16-01 and a unified equation proposed recently for several types of bolted connections. From this work, a limit states design equation is proposed for gusset plates.Key words: gusset plate, limit states design, reliability, shear rupture, tension rupture, finite element analysis, failure criterion.

Properties and Applications of Dry-Spun Carbon Nanotube Yarns

2008 ◽  
Vol 60 ◽  
pp. 11-20 ◽  
Author(s):  
Ken R. Atkinson ◽  
Chris Skourtis ◽  
S.R. Hutton
Keyword(s):  
Biomedical Applications ◽  
High Strength ◽  
Practical Applications ◽  
Good Thermal Stability ◽  
University Of Texas ◽  
Mechanical And Electrical Properties ◽  
State Process ◽  
Large Numbers ◽  
Technical Interest ◽  
Reliable Methods

Carbon nanotubes (CNTs) are of great technical interest because of their high strength (~37 GPa), good electrical conductivity, excellent thermal conductivity (3 000 W m-1K-1), and good thermal stability at both low and high temperatures. A difficulty has been absence of reliable methods of controlling assembly of the large numbers of CNTs required for practical applications. We have developed, in collaboration with our partners at the NanoTech Institute, University of Texas at Dallas, a solid-state process for spinning CNTs into yarns without the use of binders that usually degrade the electrical and thermal conductivities. The singles yarns were twisted together to give coarser (multi-stranded) stronger yarns that were knitted using a miniature 5-needle machine. Mechanical and electrical properties of the yarns and knitted tubes were assessed simultaneously using specially developed test equipment. Some specific applications under investigation include using the CNT yarns as incandescent and x-ray filaments, as electrodes for biomedical applications, and as composites with high toughness. Tests show the biocompatibility of the CNT yarns for selected cell lines is high.

Microstructures and Properties of HAZ of JB800 Bainite Steel

2014 ◽  
Vol 670-671 ◽  
pp. 65-69
Author(s):  
Jun Sheng Sun ◽  
Hong Quan Wang
Keyword(s):  
Impact Toughness ◽  
Lower Cost ◽  
Welding Process ◽  
High Strength ◽  
Granular Bainite ◽  
Low Alloy Steels ◽  
Test Results ◽  
Bainite Steel ◽  
Alloy Steels ◽  
Allotriomorphic Ferrite

JB800 steel has grain boundary allotriomorphic ferrite and granular bainite (FGBA/BG), and it is a kind of high strength low alloy steels, which has simple produce procedure, lower cost and excelled property. The law of microstructure transformation in CGHAZ, hardness, and impact toughness in HAZ of JB800 steel were studied by means of thermal simulation. The test results show that under the general condition of welding process (t8/5=5~50s), microstructure of CGHAZ is composed of mixture microstructure of Martensite and Bainite and with the increase of cooling rate, the content of Martensite will decrease, but that of Bainite will increase; when t8/5 is 20s, CGHAZ zone have better impact toughness, which is composed of 95% Martensite and 5% Bainite. Therefore t8/5 should be controlled at about 20s to get better impact toughness.

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