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

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.

2014 ◽  
Vol 592-594 ◽  
pp. 1109-1113 ◽  
Author(s):  
Dipen Kumar Rajak ◽  
L.A. Kumaraswamidhas ◽  
S. Das

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.


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


Fibers ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 69 ◽  
Author(s):  
Boon Lim ◽  
Jou-Mei Chu ◽  
Wayne Chen

In this study, we performed off-axis transverse loading experiments to study the stress concentration developed in a high-performance yarn with different indenters. A universal testing machine was utilized to perform quasi-static transverse loading experiments on Twaron® yarns. Seven different round indenters possessing radius of curvature ranging from 0.20 to 4.50 mm were employed in the experiments. In addition, post-mortem failure analysis was performed on the recovered specimens via a scanning electron microscope. From the transverse loading experiments, the results showed that, as the radius of curvature of the indenters increased, the concentrated load decreased, causing the failure surfaces to change from a combination of kink band, snapped-back, and localized shear to only fibrillations. The concentrated stresses were predicted by a strain energy model when loaded by an indenter with a radius of curvature smaller than 1.59 mm. For indenters larger than 1.59 mm, the specimens failed in fibrillation, the concentrated stresses agreed well with the stresses predicted by quasi-static circular curved beam theory.


The effect of biochar filler (carbon particle) on the mechanical properties over the inter-laminar surfaces of basalt unidirectional fabric/polyester resin is going to be scrutinized using Mode II delamination method. The ENF (end notch flexure) specimen is fabricated using hand layup method. Here basalt fabric is synthesized using unsaturated polymer resin with the help of methyl ethyl ketone peroxide and cobalt naphthenate as a catalyst. Both specimens are manufactured with and without biochar conditions. The laminate length and width will be customized as per the required dimensions of the ASTM standard. The ENF specimens are tested using the universal testing machine and the strain energy released rate and displacement of each specimen are been measured. The biochar based laminated composite has a resistant towards the fracture developed on laminated composite during testing due to the addition of carbon particles.


2014 ◽  
Vol 875-877 ◽  
pp. 534-541 ◽  
Author(s):  
Chawalit Thinvongpituk ◽  
Nirut Onsalung

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.


Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1153
Author(s):  
Franz Konstantin Fuss ◽  
Asliza Ahmad ◽  
Adin Ming Tan ◽  
Rizal Razman ◽  
Yehuda Weizman

Hard-shell thoracolumbar sacral orthoses (TLSOs) are used for treating idiopathic scoliosis, a deformation of the spine with a sideways curvature. The pressure required inside the TLSO for ideal corrective results remains unclear. Retrofitting TLSOs with commercially available pressure measurement systems is expensive and can only be performed in a laboratory. The aim of this study was to develop a cost-effective but accurate pressure sensor system for TLSOs. The sensor was built from a piezoresistive polymer, placed between two closed-cell foam liners, and evaluated with a material testing machine. Because foams are energy absorbers, the pressure-conductance curve was affected by hysteresis. The sensor was calibrated on a force plate with the transitions from loading to unloading used to establish the calibration curve. The root mean square error was 12% on average within the required pressure range of 0.01–0.13 MPa. The sensor reacted to the changing pressure during breathing and different activities when tested underneath a chest belt at different tensions. The peak pressure reached 0.135 MPa. The sensor was further tested inside the scoliosis brace during different activities. The measured pressure was 0.014–0.124 MPa. The results from this study enable cheaper and mobile systems to be used for clinical studies on the comfort and pressure of braces during daily activities.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1303
Author(s):  
Michael Seidenstuecker ◽  
Thomas Schmeichel ◽  
Lucas Ritschl ◽  
Johannes Vinke ◽  
Pia Schilling ◽  
...  

This work aimed to determine the influence of two hydrogels (alginate, alginate-di-aldehyde (ADA)/gelatin) on the mechanical strength of microporous ceramics, which have been loaded with these hydrogels. For this purpose, the compressive strength was determined using a Zwick Z005 universal testing machine. In addition, the degradation behavior according to ISO EN 10993-14 in TRIS buffer pH 5.0 and pH 7.4 over 60 days was determined, and its effects on the compressive strength were investigated. The loading was carried out by means of a flow-chamber. The weight of the samples (manufacturer: Robert Mathys Foundation (RMS) and Curasan) in TRIS solutions pH 5 and pH 7 increased within 4 h (mean 48 ± 32 mg) and then remained constant over the experimental period of 60 days. The determination surface roughness showed a decrease in the value for the ceramics incubated in TRIS compared to the untreated ceramics. In addition, an increase in protein concentration in solution was determined for ADA gelatin-loaded ceramics. The macroporous Curasan ceramic exhibited a maximum failure load of 29 ± 9.0 N, whereas the value for the microporous RMS ceramic was 931 ± 223 N. Filling the RMS ceramic with ADA gelatin increased the maximum failure load to 1114 ± 300 N. The Curasan ceramics were too fragile for loading. The maximum failure load decreased for the RMS ceramics to 686.55 ± 170 N by incubation in TRIS pH 7.4 and 651 ± 287 N at pH 5.0.


2015 ◽  
Vol 41 (3) ◽  
pp. 258-263 ◽  
Author(s):  
Angélica Castro Pimentel ◽  
Marcello Roberto Manzi ◽  
Cristiane Ibanhês Polo ◽  
Claudio Luiz Sendyk ◽  
Maria da Graça Naclério-Homem ◽  
...  

The aim of this study was to evaluate the stress distribution of different retention systems (screwed, cemented, and mixed) in 5-unit implant-supported fixed partial dentures through the photoelasticity method. Twenty standardized titanium suprastructures were manufactured, of which 5 were screw retained, 5 were cement retained, and 10 were mixed (with an alternating sequence of abutments), each supported by 5 external hexagon (4.0 mm × 11.5 mm) implants. A circular polariscope was used, and an axial compressive load of 100 N was applied on a universal testing machine. The results were photographed and qualitatively analyzed. We observed the formation of isochromatic fringes as a result of the stresses generated around the implant after installation of the different suprastructures and after the application of a compressive axial load of 100 N. We conclude that a lack of passive adaptation was observed in all suprastructures with the formation of low-magnitude stress in some implants. When cemented and mixed suprastructures were subjected to a compressive load, they displayed lower levels of stress distribution and lower intensity fringes compared to the screwed prosthesis.


2013 ◽  
Vol 438-439 ◽  
pp. 220-223 ◽  
Author(s):  
Ling Zhang ◽  
Chun Ling Yan

Cube concrete (150×150×150mm) of five ages (7, 14, 21, 28 and 35 days) under different stress conducted the ultrasound examination by non-metallic detector and universal testing machine. The results show that the relationship curve of the stress and the ultrasonic velocity can be divided into three stages, the smooth straight stage, the linear deceleration stage and the attenuation destruction stage from the load beginning to the ultimate strength for the same age. There is a growing trend about the ultrasonic velocity with the increase of the age to concrete samples of C10 and C20 in the same loading; however, the overall growth trend of the velocity is not obvious to concrete samples of C30, C35, C40 and C45. It also shows that the relationship curve of strength level and the velocity can be divided into two distinct stages, the sharply increasing stage (C10-C30) and the fluctuating stage (C30-C45). Simultaneously, the paper further illustrates and explains the reasons to appear these stages and the phenomena.


2015 ◽  
Vol 819 ◽  
pp. 411-416
Author(s):  
S.N. Fitriah ◽  
M.S. Abdul Majid ◽  
R. Daud ◽  
M. Afendi ◽  
Z.S. Nazirah

The paper discusses the crushing behavior of glass fibre reinforced epoxy (GRE) pipes under hydrothermal ageing condition. This study determines the behavior of the GRE pipes when subjected to different ageing periods and temperatures. Hydrothermal ageing has been found to cause degradation between resin and fibre interface thus causing the reduction in the strength of composite laminates. The pipes were subjected to hydrothermal condition to simulate and precipitate ageing by immersing the pipe samples in water at 80°C for 250, 500, and 1000 hours. Compression tests were carried out using Universal Testing Machine (UTM) for virgin condition and aged samples in accordance with ASTM D695 standard. The maximum force at the initial failure region is observed for each of the conditioned pipes. The results show that the strength of the matrix systems was considerably degraded due to the plasticization of the matrix system.


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