scholarly journals Characteristics of Rectangular Section and Double Hat Section

2019 ◽  
Vol 9 (2S4) ◽  
pp. 457-460
Keyword(s):  
Energy Absorption ◽  
Testing Machine ◽  
Primary Objective ◽  
Rectangular Section ◽  
Universal Testing ◽  
Collapse Mode ◽  
Post Test ◽  
The Difference ◽  
Energy Absorbers ◽  
Energy Absorbing

This proposal defines the difference between the double hat section tubes &rectangular section for tremble energy consumption like in crash worth applications. The primary objective of this study is to “to gather information regarding the energy absorption & impact of double and single cap section tubes and to apply them in the system where energy absorption takes place.The double-hat and thin-walled top-hat in which spot-welded by quasi-static axial method. Many tests were identified such as associated energy-absorbing characteristics and several post-test collapse mode where scrutinized and compared with other previous tests. The best model was selected by crush analysis in universal testing machine by comparison of parameters such as mean force and energy absorbers. The efficient model is selected by comparatively lesser mean force and higher energy absorption

Crush Response of Polyurethane Foam-Filled Aluminium Tube Subjected to Axial Loading

2014 ◽  
Vol 875-877 ◽  
pp. 534-541 ◽  
Author(s):  
Chawalit Thinvongpituk ◽  
Nirut Onsalung
Keyword(s):  
Energy Absorption ◽  
Polyurethane Foam ◽  
Testing Machine ◽  
Axial Loading ◽  
Asymmetric Mode ◽  
Pu Foam ◽  
Universal Testing ◽  
Collapse Mode ◽  
Empty Tube ◽  
Foam Filled

In this paper, the experimental investigation of polyurethane (PU) foam-filled into circular aluminum tubes subjected to axial crushing was presented. The purpose of this study is to improve the energy absorption of aluminium tube under axial quasi-static load. The aluminium tube was made from the AA6063-T5 aluminium alloy tubes. Each tube was filled with polyurethane foam. The density of foam was varied from 100, 150 and 200 kg/mP3P including with empty tube. The range of diameter/thickness (D/t) ratio of tube was varied from 15-55. The specimen were tested by quasi-static axial load with crush speed of 50 mm/min using the 2,000 kN universal testing machine. The load-displacement curves while testing were recorded for calculation. The mode of collapse of each specimen was analyzed concerning on foam density and the influence of D/t ratio. The results revealed that the tube with foam-filled provided significantly increment of the energy absorption than that of the empty tube. While the density of foam and D/t ratios increase, the tendency of collapse mode is transformed from asymmetric mode to concertina mode.

scholarly journals Reversed-torsion-type crush energy absorption structure and its inexpensive partial-heating torsion manufacturing method based on origami engineering

2021 ◽  
pp. 1-31
Author(s):  
Xilu Zhao ◽  
Chenghai Kong ◽  
Yang Yang ◽  
Ichiro Hagiwara
Keyword(s):  
Energy Absorption ◽  
Peak Load ◽  
Point Of View ◽  
Building Structures ◽  
Manufacturing Method ◽  
Partial Heating ◽  
Vehicle Structure ◽  
Energy Absorbers ◽  
Energy Absorbing ◽  
Origami Engineering

Abstract Current vehicle energy absorbers face two problems during a collision in that there is only a 70% collapse in length and there is a high initial peak load. These problems arise because the presently used energy-absorbing column is primitive from the point of view of origami. We developed a column called the Reversed Spiral Origami Structure (RSO), which solves the above two problems. However, in the case of existing technology of the RSO, the molding cost of hydroforming is too expensive for application to a real vehicle structure. We therefore conceive a new structure, named the Reversed Torsion Origami Structure (RTO), which has excellent energy absorption in simulation. We can thus develop a manufacturing system for the RTO cheaply. Excellent results are obtained in a physical experiment. The RTO can replace conventional energy absorbers and is expected to be widely used in not only automobile structures but also building structures.

Key Performance Indicators of Tubes Used as Energy Absorbers

2014 ◽  
Vol 626 ◽  
pp. 155-161 ◽  
Author(s):  
T.X. Yu ◽  
Yan Fei Xiang ◽  
Min Wang ◽  
Li Ming Yang
Keyword(s):  
Energy Absorption ◽  
Carrying Capacity ◽  
Performance Indicators ◽  
Key Performance Indicators ◽  
Absorption Capacity ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Engineering Designs ◽  
Energy Absorbers ◽  
Energy Absorbing

Based on our extensive studies on the experimental, theoretical and numerical results on various tubes under axial compression/impact in the last few years, we propose a set of Key Performance Indicators (KPIs) to assess and compare the energy absorbing performance of tubular structures with various configurations, so as to guide the design of energy absorbers whilst to archive a certain degree of optimization. The KPIs have five factors: Effective stroke ratio (ESR), Non-dimensional Load-carrying capacity (NLC), Effectiveness of energy absorption (EEA), Specific energy absorption capacity (SEA), Stableness of load-carrying capacity (SLC).The paper presents a series of diagrams to compare the energy absorbing performance of various tubes in terms of the four KPIs as described above. The work is valuable to engineering designs and applications, as well as to the further studies of the topic.

Experimental Investigation of Energy Absorption of ‎Partially Wrapped Thin-Walled ‎Aluminium-Glass/Epoxy Tube Subjected to Quasi-Static Loading

2017 ◽  
Vol 904 ◽  
pp. 61-67
Author(s):  
Tahir Abbas ◽  
Hamdan H. Ya ◽  
Mohamad Zaki Abdullah
Keyword(s):  
Experimental Investigation ◽  
Energy Absorption ◽  
Fiber Orientation ◽  
Static Loading ◽  
Failure Modes ◽  
Testing Machine ◽  
Filament Winding ◽  
Universal Testing ◽  
Thin Walled ◽  
Filament Winding Process

This paper describes the failure modes and energy absorption capability of partially wrapped aluminium-glass/epoxy tubes, subjected to quasi-static loading. ‎These tubes are used in aircraft and automobiles applications. Aluminium tubes were partially wrapped with 4, 6 and 8 glass/epoxy layers, using filament winding process. The 90◦ fiber orientation was used for glass/epoxy layers. Quasi-static loading of partially wrapped tubes was carried out at 5mm/min speed, using the universal ‎testing machine. The experimental results revealed that partially wrapped aluminium tubes are 42.54%, 47.77% and 28.91% more ‎efficient in energy absorption as compared to the simple aluminium tubes. Furthermore, the effect of glass/epoxy layers on ‎failure modes has also been described.

scholarly journals Pengaruh Komposisi Glass Fiber Non Dental dan Penambahan Silane terhadap Kekuatan Geser Fiber Reinforced Composite sebagai Retainer Ortodonsi

2015 ◽  
Vol 1 (1) ◽  
pp. 53
Author(s):  
Dian Noviyanti Agus Imam ◽  
Siti Sunarintyas ◽  
Nuryono Nuryono
Keyword(s):  
Bond Strength ◽  
Glass Fiber ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Fiber Reinforced ◽  
Fiber Reinforced Composite ◽  
Fiber Composition ◽  
Reinforced Composite ◽  
Universal Testing ◽  
Post Test

Retainer dibutuhkan untuk membantu menstabilkan posisi gigi geligi selama proses reorganisasi jaringan periodontal berlangsung. Retainer FRC ortodonsi dikembangkan sebagai alternatif material estetika serta aman bagi pasien alergi terhadap nikel. E-glass fiber lebih sering digunakan sebagai retainer ortodonsi. Penelitian ini bertujuan untuk mengkaji pengaruh komposisi glass fiber non dental dan penambahan silane terhadap kekuatan geser FRC sebagai retainer ortodonsi. Subjek penelitian terdiri dari 9 kelompok perlakuan dengan 3 jenis glass fiber yang berbeda yaitu glass fiber non dental A (LT, Cina), B (CMAX, Cina) dan C (HJ, Cina). Masing-masing glass fiber diberi perlakuan yang bervariasi yaitu tanpa penambahan silane, penambahan silane 1x dan 2x. Subjek penelitian direndam dalam akuades dan disimpan pada suhu 37ºC selama 24 jam sebelum dilakukan uji kekuatan geser dengan menggunakan alat Universal Testing Machine. Hasil penelitian dianalisis variansi dua jalur dan post hoc Tukey untuk mengetahui perbedaan statistik masing-masing kelompok. Hasil penelitian menunjukkan bahwa glass fiber non dental A dengan penambahan 2x silane memiliki rerata kekuatan geser tertinggi (12,72±2,02 MPa) sedangkan glass fiber non dental B tanpa penambahan silane memiliki rerata kekuatan geser terendah (6,96±1,69 MPa). Terdapat perbedaan bermakna antara komposisi fiber maupun penambahan silane terhadap kekuatan geser FRC (p<0,05). Tidak terdapat perbedaan bermakna pada letak kegagalan FRC (p>0,05). Berdasarkan hasil penelitian dapat disimpulkan bahwa komposisi SiO2 dan Al2O3 yang tinggi pada glass fiber non dental serta penambahan silane dapat meningkatkan kekuatan geser FRC. The Effect of Non Dental Glass Fiber Composition and Silane Addition on The Shear Bond Strength of Fiber Reinforced Composite as An Orthodontic Retainer. Retainers are required to stabilize the position of the teeth to permit reorganization of periodontal tissue. FRC orthodontic retainer was developed as an alternative material aesthetic and safe for nickel allergic patients. E-glass fiber is commonly used as an orthodontic retainer. The purpose of this study was to assess the effect of non dental glass fiber composition and silanes addition on the shear bond strength of the FRC as an orthodontic retainer. This study consisted of 9 treatment groups with three different types of non dental glass fiber, namely non dental glass fiber A (LT, China), B (CMAX, China) and C (HJ, China). Each glass fiber was given a variation treatment, without silanes, one time and two times of silanes addition. All the samples were stored in distilled water at 37ºC for 24 hours and subsequently tested for shear strength by using Universal Testing Machine.The groups were submitted to two way ANOVA analysis of variance with Tukey post test to verify the statictical difference between groups. The results showed that a non dental glass fiber A with two times of silanes addition has the highest shear bond strength (12,72±2,02 MPa), meanwhile a non dental glass fiber B without silane addition has the lowest shear bond strength (6,96±1,69 MPa). There were significant differences between the composition of glass fiber and the addition of silane toward the shear bond strength of FRC (p<0,05). No significant differences in debonded locations of FRC (p>0,05). Based on the results of this study concluded that the composition of the high SiO2 and Al2O3 in the non dental glass fiber  and the silanes addition can increase the shear bond strength FRC.

scholarly journals Statistical Analysis of Tensile Strength and Flexural Strength Data from Universal Testing Machine

2020 ◽  
pp. 54-62
Author(s):  
Ahmad Adlie Shamsuri ◽  
Siti Atiqa Al Zahra Mat Darus
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Testing Machine ◽  
Z Score ◽  
P Values ◽  
Strength Data ◽  
Universal Testing Machine ◽  
Universal Testing ◽  
Relative Standard ◽  
The Difference

The tensile strength and flexural strength are the most important mechanical properties as they provide the value of maximum tensile stress and flexural stress. The objective of this study is to analyze statistically the tensile strength and flexural strength data obtained from a universal testing machine. The tests were conducted upon a thermoplastic, specifically high-density polyethylene (HDPE), which was in-house molded by using an injection-molding machine. Three different persons have performed the tensile and flexural tests. Three other laboratories have also been involved in these tests. The relative standard deviation (RSD) values were calculated to express the precision and repeatability of the tests. Later, the standard score (z-score) values were also calculated to aid the comparison of the data. Finally, the single-factor analysis of variance (ANOVA) was employed to investigate statistically significant differences between the means of the tensile strength and flexural strength data of each person and laboratory. From the calculation, the RSD values of all three persons and laboratories were lower than 5%, indicating that the data were consistent. The z-score values of all three persons were within the range from -2 to 2, suggesting that the data were close to average. However, the z-score value for one of three laboratories was not within the range, demonstrating that the data was unusual. The P-values of all three persons were higher than 0.05 (except for flexural strength), implying that the difference between the means of the data was not statistically significant. Nevertheless, the P-values of all three laboratories were lower than 0.05, indicating that the difference between the means of the data was statistically significant.

scholarly journals Effect of the Degree of Conversion on Mechanical Properties and Monomer Elution from Self-, Dual- and Light-Cured Core Composites

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5642
Author(s):  
Branislava Petronijevic Sarcev ◽  
Sebastian Balos ◽  
Dubravka Markovic ◽  
Ivan Sarcev ◽  
Marija Vukcevic ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Vickers Hardness ◽  
Modulus Of Elasticity ◽  
Testing Machine ◽  
Degree Of Conversion ◽  
Clinical Use ◽  
Universal Testing ◽  
Post Test ◽  
One Way Anova

The objective of this work was to measure and correlate the degree of conversion (DC), mechanical properties and monomer elution from self-, dual- and light-cured core composites. Five samples of each of the following materials were prepared for each test: Clearfil (Core, Photo Core, Automix), Bisco (Core-Flo, Light-Core and Bis-Core). DC was determined using FTIR, compressive and flexural strength and modulus of elasticity using a universal testing machine and microhardness using Vickers hardness. Elution was measured using HPLC. One-way ANOVA with Tukey’s post-test and Pearson’s correlation were used to statistically analyze the data. DC of Clearfil-Dual (70.1%) and Clerafil-Photo (66.8%) were higher than Clearfil-Self (55.4%) and all Bisco materials (51.4–55.3%). Flexural strength of Clearfilwas higher than that of Bisco composites. The Microhardness of Clearfil-Dual (119.8VHN) and Clearfil-Photo (118.0VHN) were higher compared to other materials. The greatest elution was detected from self-cured materials. DC positively correlated to microhardness and compressive/flexural strength and negatively to BisGMA elution. Clearfil-Photo and Automix showed higher conversion, lower monomer elution and, generally, better mechanical properties. Self-cured composites should not be recommended for routine clinical use as their performance was inferior to dual- and light-cured composites. Microhardness may be used as an indicator of elution.

scholarly journals Influence of Geometry in the Behavior of Disc-Shaped Mechanical Energy Absorbers for Agricultural Tractors

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2594
Author(s):  
Juan-Ignacio Latorre-Biel ◽  
Amaya Pérez-Ezcurdia ◽  
Marta Benito-Amurrio ◽  
José Ramón Alfaro-López
Keyword(s):  
Strain Energy ◽  
Linear Models ◽  
Mechanical Energy ◽  
Testing Machine ◽  
Characteristic Parameters ◽  
Safety Zone ◽  
Universal Testing ◽  
Energy Absorbers ◽  
Agricultural Tractors ◽  
Agricultural Tractor

Disc-shaped mechanical energy absorbers (MEAs), in combination with rollover protection structures (ROPSs), may contribute to the prevention of the infringement of the safety zone and the collapse of the ROPS in case of the overturn of an agricultural tractor. An MEA can absorb a significant amount of potential energy of an overturning tractor and its deformation produces a rotation of the ROPS around the safety zone. In this research, MEAs with two different geometries have been developed. Both geometries present common features, such as disc dimensions, number of rings, and number of arms, but the distribution of the arms differs. Additionally, these MEA were manufactured in steel discs of four different thicknesses, ranging from 2 to 6 mm. The manufactured MEAs were tested in a universal testing machine, and their behavior characterized. From this data, linear models of the MEAs were developed. As a consequence, a number of characteristic parameters were selected and calculated, such as the activation load and the strain energy absorbed in a safe range of applied loads. Some patterns and trends were analyzed from the tested MEAs, which enables a better description of their behavior and the extrapolation of this behavior to other non-tested thicknesses and geometries.

scholarly journals Introducing the Team Based Learning as an Approach to Reviving Interest in Biochemistry amongst Undergraduate Medical Students-An Exploratory Study

2017 ◽  
Vol 53 (03) ◽  
pp. 166-174
Author(s):  
Vanita Lal ◽  
Bharti Bhandari ◽  
Garima Gupta ◽  
Kuldeep Singh ◽  
Praveen Sharma
Keyword(s):  
Medical Students ◽  
Team Building ◽  
Primary Objective ◽  
Difficulty Level ◽  
Random Allocation ◽  
Undergraduate Medical Students ◽  
Lecture Method ◽  
Feedback Questionnaire ◽  
Post Test ◽  
The Difference

ABSTRACT Introduction: Much emphasis has been given to different approaches to active learning. Our primary objective was to elicit interest amongst students in the areas of neglected, difficult topics in Biochemistry. Encouraging team building and developing team spirit by roping in all students in the exercise was the secondary objective of our study. Methods: It was a single blind controlled interventional study. ATeam Based Learning (TBL) Module was developed for First Professional MBBS students of 2015 batch. The topics selected were of high difficulty level. Ten groups were formed by random allocation. Study materials and reference sources were displayed and distributed two weeks prior to the initiation of TBL sessions. Each TBL session consisted of pre-test preparation (through didactic lectures and self-study), MCQ-based pre-test, application of concepts, Problem Based Questions (PBQs), reviewing and post-test. This was followed by administration of feedback questionnaire. The data obtained were analysed using SPSS version 21. Results: When the pre-test and post-test marks were compared, significant improvement in the students' performance was observed (p<0.05). According to students' feedback, the learning exercise was innovative, beneficial, helped in better comprehension of difficult topics, increased in-depth knowledge on the topic, fun-filled and relaxing, eventually leading to better learning. Students were able to analyse and give rational and logical responses to complex PBQs. There was an increase in interest towards reading and referring in detail about the topics allotted to them. Library usage and issue of reference books as seen in the logbook increased rapidly. They were more confident in Biochemistry after conducting a series of TBL sessions. While comparing the performance marks after the TBL sessions with that after classroom didactic lecture method, students were of the view that TBL was better than lectures. The difference in scores obtained by two groups (2016 vs. 2015) was significant. The groups who were exposed to TBL had far better scores than those exposed to lectures in the same topic. Conclusion: The focus these days is on self-directed learning for medical students to become self-regulated, independent learners, which is essential for acquiring competencies and TBL appears to be one such modality.

Mechanical Behaviour and Energy Absorption Foam Filled Structures of Square Section under Compression Loading

2014 ◽  
Vol 592-594 ◽  
pp. 1109-1113 ◽  
Author(s):  
Dipen Kumar Rajak ◽  
L.A. Kumaraswamidhas ◽  
S. Das
Keyword(s):  
Energy Absorption ◽  
Mechanical Energy ◽  
Testing Machine ◽  
Aluminium Foam ◽  
Strain Rates ◽  
Universal Testing ◽  
Good Energy ◽  
Foam Filled ◽  
Steel Foam ◽  
Compressive Tests

The focus of this paper is to study the energy absorption characteristics of aluminium foam filled sections. The energy absorption capability of square mild steel foam filled and empty samples to absorbed mechanical energy have been estimated according to the results from the compressive tests. The tests were performed on the universal testing machine .The experimental results shows that aluminium foam filled sections feature have good energy absorption at various strain rates from 10-3/s to 10/s.

Sign in / Sign up

Export Citation Format

Share Document