A Performance Study on Self-Piercing Riveting and Adhesive Hybrid Joints of Different Adhesive

2014 ◽  
Vol 887-888 ◽  
pp. 1261-1264
Author(s):  
Fu Long Liu ◽  
Xiao Cong He ◽  
Yu Qi Wang
Keyword(s):  
Failure Mechanism ◽  
Energy Absorption ◽  
Failure Mode ◽  
Failure Modes ◽  
Test Results ◽  
Performance Study ◽  
Strength Capacity ◽  
Hybrid Joints ◽  
Overall Performance ◽  
Tension Loading

This paper studied the performance of self-piercing riveting (SPR) and adhesive hybrid joints of different adhesive, including strength, capacity of energy absorption, failure mode and failure mechanism of the hybrid joints. The performances of SPR-adhesive hybrid joints were compared with SPR joints. SPR-adhesive hybrid joints and SPR joints were tested under a tension loading. The test results showed that adhesive have a function of improving the strength of SPR joints; however, the capacity of energy absorption of SPR joints was weakened. While the adhesive have no effect on the failure modes of SPR joints. When appropriate adhesive was selected, the overall performance of SPR-adhesive hybrid joints was superior to SPR joints. In a word, the combination of SPR and adhesive could get a well jointing structure.

Assesment of Main Models for Predicting Debonding Load-Bearing Capacity against Intermediate Crack-Induced Debonding Failure in FRP-Strengthened RC Beams

2011 ◽  
Vol 311-313 ◽  
pp. 1941-1944
Author(s):  
Gui Bing Li ◽  
Yu Gang Guo ◽  
Xiao Yan Sun
Keyword(s):  
Bearing Capacity ◽  
Failure Mode ◽  
Failure Modes ◽  
Rc Beams ◽  
Test Results ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Accuracy Test ◽  
New Models ◽  
Debonding Load

intermediate crack-induced debondingis one of the most dominant failure modes in FRP-strengthened RC beams. Different code models and provisions have been proposed to mitigateintermediate crack-induced debondingfailure.However, these models and provisions can not mitigate this failure mode effectively. Recnetly, new models have been proposed to solve this problem. Out of all the existing models, four typical ones are investigated in the current study. A comprehensivecomparison among these models is carried out in order to evaluate their performance and accuracy. Test results offlexural specimens with intermediate crack-induced debonding failurecollected from the existing literature are used in the current comparison. The effectivenessand accuracy of each model have been evaluated based on these experimental results. It is shown that the current modals are all conservative and inadequite to effectively mitigate intermediate crack-induced debonding in flexurally strengthened members.

Failure Modes of a Laminated Composite With Complaint Interlayers

2020 ◽  
Vol 88 (3) ◽  
Author(s):  
M. R. O’Masta ◽  
V. S. Deshpande
Keyword(s):  
Failure Mechanism ◽  
Failure Mode ◽  
Failure Modes ◽  
Volume Fraction ◽  
Flexural Rigidity ◽  
Laminated Composite ◽  
High Volume ◽  
Tensile Fracture ◽  
Reduced Order ◽  
Fe Simulations

Abstract Composites comprising a high-volume fraction of stiff reinforcements within a compliant matrix are commonly found in natural materials. The disparate properties of the constituent materials endow resilience to the composite, and here we report an investigation into some of the mechanisms at play. We report experiments and simulations of a prototype laminated composite system comprising silicon layers separated by polymer interlayers, where the only failure mechanism is the tensile fracture of the brittle silicon. Two failure modes are observed for such composites loaded in three-point bending: failure under the central roller in (i) the top ply (in contact with the roller) or (ii) the bottom ply (free surface). The former mode is benign with the beam retaining load carrying capacity, whereas the latter leads to catastrophic beam failure. Finite element (FE) simulations confirm this transition in failure mode and inform the development of a reduced order model. Good agreement is shown between measurements, FE simulations, and reduced order predictions, capturing the effects of material and geometric properties on the flexural rigidity, first ply failure mode, and failure load. A failure mechanism map for this system is reported that can be used to inform the design of such laminated composites.

scholarly journals Behavior of wood beam connection using staples subjected to in-plane moment

2019 ◽  
Vol 258 ◽  
pp. 05008
Author(s):  
Farida Lenggani ◽  
Bambang Suryoatmono
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Solid Wood ◽  
Experimental Results ◽  
Elastic Analysis ◽  
Connection Strength ◽  
Test Results ◽  
Lateral Resistance ◽  
Wood Beams ◽  
Mechanical Fasteners

It is very frequent that solid wood beams need to be connected one to another to obtain a longer beam. In this study, the behavior of solid wood beams connections using plywood sheets as connecting elements and staples as mechanical fasteners were studied experimentally. The experimental results were compared with elastic analyses. Both beam and plywood were made of meranti (shorea). The staple type was MAX 1022J. This study was conducted on two specimens. The first specimen had two rows of staples on the front and back sides of the specimen. Each row consisted of ten staples making a total of 40 staples. The second one had three rows of staples on the front and back sides of the specimen. Each row consisted of ten staples making a total of 60 staples. From the tests, it can be concluded that each material in the connection, namely wood beam, plywood, and staples, failed. Failure mode of the wood beam was in the form of crack and tear. Failure mode of the plywood was the damage of the plywood directly contacted with the crown of the staples. Failure modes of the staples were flexural yielding. The differences between connection strength obtained from tests and elastic analyses were 8.18% for the first specimen and 0.65% for the second specimen, with the test results were higher than the elastic analyses results. It can be concluded that elastic analysis is quite accurate and conservative to estimate the strength of this type of connection, provided that the lateral resistance of connection with a staple is known.

scholarly journals Improving Ballistic Performance of Polyurethane Foam by Nanoparticle Reinforcement

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
M. F. Uddin ◽  
H. Mahfuz ◽  
S. Zainuddin ◽  
S. Jeelani
Keyword(s):  
Energy Absorption ◽  
Polyurethane Foam ◽  
High Speed ◽  
Failure Modes ◽  
High Speed Camera ◽  
Test Results ◽  
Ballistic Performance ◽  
Gas Gun ◽  
Set Up ◽  
Control Samples

We report improving ballistic performance of polyurethane foam by reinforcing it with nanoscaleTiO2particles. Particles were dispersed through a sonic cavitation process and the loading of particles was 3 wt% of the total polymer. Once foams were reinforced, sandwich panels were made and impacted with fragment simulating projectiles (FSPs) in a 1.5-inch gas gun. Projectile speed was set up to have complete penetration of the target in each experiment. Test results have indicated that sandwich with nanophased cores absorbed about 20% more kinetic energy than their neat counterpart. The corresponding increase in ballistic limit was around 12% over the neat control samples. The penetration phenomenon was also monitored using a high-speed camera. Analyses of digital images showed that FSP remained inside the nanophased sandwich for about 7 microseconds longer than that of a neat sandwich demonstrating improved energy absorption capability of the nanoparticle reinforced core. Failure modes for energy absorption have been investigated through a microscope and high-speed images.

scholarly journals A Study of Multi-Objective Crashworthiness Optimization of the Thin-Walled Composite Tube under Axial Load

Vehicles ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 438-452
Author(s):  
Mohammad Reza Seyedi ◽  
Abolfazl Khalkhali
Keyword(s):  
Failure Mechanism ◽  
Energy Absorption ◽  
Failure Modes ◽  
Matrix Material ◽  
Load Condition ◽  
Fe Model ◽  
Absorption Mechanism ◽  
Multi Objective ◽  
Thin Walled ◽  
The Impact

In recent decades, thin-walled composite components have been widely used in the automotive industry due to their high specific energy absorption. A large number of experimental and numerical studies have been conducted to characterize the energy absorption mechanism and failure criteria for different composite tubes. Their results indicate that the energy absorption characteristics depend highly on the failure modes that occur during the impact. And failure mechanism is dependent on fiber material, matrix material, fiber angle, the layout of the fibers, as well as the geometry of structure and load condition. In this paper, first, the finite element (FE) model of the CFRP tube was developed using the Tsai-Wu failure criterion to model the crush characteristics. The FE results were validated using the published experimental. Then, a series of FE simulations were conducted considering different fiber directions and the number of layers to generate enough data for constructing the GMDH-type neural network. The polynomial expression of the three outputs (energy absorption, maximum force, and critical buckling force) was extracted using the GMDH algorithm and was used to perform the Pareto-based multi-objective optimizations. Finally, the failure mechanism of the optimum design point was simulated in LS-DYNA. The main contribution of this study was to successfully model the CFRP tube and damage mechanism using appropriate material constitutive model’s parameters and present the multi-objective method to find the optimum crashworthy design of the CFRP tube.

Behaviour of adhesive steel anchors under impulse-type loading

2009 ◽  
Vol 36 (11) ◽  
pp. 1835-1847 ◽  
Author(s):  
Abass Braimah ◽  
Ettore Contestabile ◽  
Rick Guilbeault
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Dynamic Behaviour ◽  
Stone Masonry ◽  
Experimental Program ◽  
Embedment Depth ◽  
Test Results ◽  
Dynamic Increase Factor ◽  
Adhesive Anchors

The dynamic behaviour of adhesive anchors embedded in concrete is not well established, neither is their behaviour in stone masonry. This paper presents an experimental program designed to study the dynamic behaviour of adhesive anchor – substrate systems under impulse-type loading. The adhesive anchor – substrate systems consisted of steel rods bonded to concrete and limestone with an epoxy-based adhesive. Two steel anchor diameters (6.4 and 9.5 mm), two embedment depths (89 and 114 mm), and two angles of substrate penetration (90° and 45°) were investigated. The predominant failure mode observed for the steel anchor – concrete substrate samples was steel fracture, whereas for the steel anchor – limestone substrate samples, both steel fracture and limestone substrate failure modes were observed. The test results show that in most cases the dynamic increase factor (DIF) of adhesive anchors decreases with an increase in the embedment depth. Also, a substrate penetration angle of 45° increases the DIF in comparison with samples with 90° penetration angle. The DIFs of 1.2 and 2.5 are recommended for adhesive anchors with normal and 45° limestone substrate penetrations, respectively, while for concrete substrate, the recommended DIFs are 1.2 and 3.2 for normal and 45° substrate penetrations, respectively.

Researches on the Test of Web Local Failure Modes and Related FEA Study

2017 ◽  
Author(s):  
Wenyu Xiao ◽  
Bingbing Liang
Keyword(s):  
Failure Mechanism ◽  
Carrying Capacity ◽  
Nuclear Power ◽  
Evaluation Method ◽  
Failure Modes ◽  
Steel Structure ◽  
Local Failure ◽  
Steel Beam ◽  
Test Results ◽  
Local Yielding

In the analysis of structure steel beam member of mechanical module and piping support in nuclear power plant, beam web shall be analyzed complying with the ASME III NF requirements against web local failure including web local yielding, web local crippling, web sideway buckling and web compression buckling when the beam is subjected to concentrated loads. Referring to the H Type steel structure beam of China GB code; this paper researches the tests of carrying capacity related to the above mentioned local failure mechanism. The results could show that the evaluation method of web local failure mechanism in ASME III NF cover the China GB code steel structure member on one hand; And on the other hand, the results could show the rationalities of the sectional dimension design of the member and the rationality of the beam span. And based on the analysis of the test results, reasonable suggestions could made for the above mentioned member dimension design and beam span design.

scholarly journals Influence of Fissure Number on the Mechanical Properties of Layer-Crack Rock Models under Uniaxial Compression

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yun-liang Tan ◽  
Wei-yao Guo ◽  
Tong-bin Zhao ◽  
Feng-hai Yu ◽  
Bin Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bearing Capacity ◽  
Failure Mechanism ◽  
Uniaxial Compression ◽  
Rational Design ◽  
Failure Modes ◽  
Test Results ◽  
Active Stage ◽  
Engineering Project ◽  
Nonuniform Deformation

Many case studies have revealed that rock bursts generally occur in the high stress concentration area where layer-crack structures often exist, especially for brittle coal or rock masses. Understanding the mechanical properties of layer-crack rock models is beneficial for rational design and stability analysis of rock engineering project and rock burst prevention. This study experimentally investigated the influence of fissure number on the mechanical properties of layer-crack rock models through uniaxial compression tests. The digital speckle correlation method (DSCM) and acoustic emission (AE) techniques were applied to record and analyze the information of deformation and failure processes. Test results show the following: the bearing capacity of layer-crack specimen decreases compared with intact specimen, but their failure modes are similar, which are the splitting failure accompanied with local shear failure; the nonuniform deformation phenomenon begins to appear at the elastic deformation stage for layer-crack specimens; the AE behavior of intact specimens consists of three stages, that is, active stage, quiet stage, and major active stage, but for layer-crack specimens, it is characteristic by three peaks without quiet stage. In addition, as the fissure number of layer-crack specimens increases, the bearing capacity of specimens decreases, the appearing time of nonuniform deformation phenomenon in the specimen surface decreases, the AE events are denser and denser in each peak stage, and the risk of dynamic instability of layer-crack structure increases. At last, the failure mechanism of layer-crack structure and the related mitigation advices were discussed based on the test results. In general, the novelty is that this paper focuses on the failure mechanism of layer-crack structure directly.

scholarly journals Joining thin-walled structures without protuberance by two-strokes flattening clinching process

2021 ◽  
Author(s):  
Hao Peng ◽  
Chao Chen ◽  
Haijun Li ◽  
Xiaolei Gao
Keyword(s):  
Energy Absorption ◽  
Failure Mode ◽  
Material Flow ◽  
Failure Modes ◽  
Mechanical Response ◽  
Flow Analysis ◽  
Material Flow Analysis ◽  
Mechanical Behaviors ◽  
Thin Walled Structures ◽  
Static Conditions

Abstract Clinching technologies have better performance in joining different sheet materials. However, the protuberance and mechanical behaviors of clinched joints have always been needed to be improved. In this paper, a new clinching method, named two-strokes flattening clinching (TFC) process, was proposed to improve the mechanical behaviors of joints and flatten the protuberance. Mechanical testing including tension shearing tests were employed under quasi-static conditions to evaluate the different mechanical behaviors between TFC and conventional clinched joints. The influences of the different forming forces on mechanical response of these joints were studied. The static strength, energy absorption, material flow and failure modes of TFC and conventional clinched joints were investigated comparatively. The experimental results demonstrated that the tension-shear strength of TFC clinched joints was increased by 30.3% compared with conventional clinched joints at the forming force of 30 kN. Furthermore, the material flow analysis showed that the thickness and interlock of TFC clinched joints were increased by 79% and 45.9%, respectively. The energy absorption of TFC clinched joint was increased by 82%. In addition, the TFC process did not change the failure mode of clinched joints, and the failure mode of all clinched joints was neck fracture.

Influence of Rubber Content on Failure Mode and Resistance Characteristics of PC/ABS Blends and their ABS Constituents under Impact

2021 ◽  
Vol 892 ◽  
pp. 67-73
Author(s):  
Muhammad Nizar Machmud ◽  
Masaki Omiya ◽  
Hirotsugu Inoue ◽  
Kikuo Kishimoto
Keyword(s):  
Impact Toughness ◽  
Impact Strength ◽  
Failure Mode ◽  
Room Temperature ◽  
Failure Modes ◽  
Impact Test ◽  
Rubber Particle ◽  
Test Results ◽  
Rubber Content ◽  
Particle Content

This present study has been re-established to investigate failure mode and resistance characteristics of the PC/ABS blends and their ABS constituents under impact for a range of rubber contents. This present study has still been experimentally performed under an instrumented-drop weight impact test (DWIT) at a room temperature. It has been finally revealed that with a particular size of rubber particle, content of rubber significantly influenced impact failure modes and impact resistances of the PC/ABS blends and their ABS constituents as well. The test results showed that impact strength of the blends was improved about 23.22% and 155.33% due to increase in content of rubber up to 15 wt% and 20 wt%, respectively. There was also found that an increase in impact toughness of the blends for 57.48% and 239.23% was due to increase in content of rubber up to 15 wt% and 20 wt%, respectively. Whilst, impact strength of the ABS was improved about 392.98% and 190.12% due to increase in content of rubber up to 15 wt% and 20 wt%, respectively. An increase in impact toughness of the ABS for 308.20% and 172.56% was due to increase in content of rubber up to 15 wt% and 20 wt%, respectively.

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