scholarly journals A novel set-up for theex vivoanalysis of mechanical properties of mouse aortic segments stretched at physiological pressure and frequency

2016 ◽  
Vol 594 (21) ◽  
pp. 6105-6115 ◽  
Author(s):  
Arthur J. A. Leloup ◽  
Cor E. Van Hove ◽  
Ammar Kurdi ◽  
Sofie De Moudt ◽  
Wim Martinet ◽  
...  

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4613-4618 ◽  
Author(s):  
R. J. T. LIN ◽  
D. BHATTACHARYYA ◽  
S. FAKIROV

Being a fast growing plastic manufacturing industry, rotational molding has been using the linear polyethylenes extensively as the raw material. As these materials have shown insufficient mechanical properties for certain applications where strength and stiffness of the products are the main concerns, worldwide rotational molders have expressed a need for stronger and stiffer materials to be available for rotomolding. A possible attractive solution may be the recently developed microfibril reinforced composites (MFCs). Blends of linear medium density polyethylene/polyethylene terephthalate (LMDPE/PET) with an MFC structure are manufactured on a commercial-scale set-up and thereafter used in rotational molding. The samples are characterized morphologically and tested mechanically. The results obtained show that the MFC-concept has good application opportunities in the polymer processing including rotational molding.



2007 ◽  
Vol 344 ◽  
pp. 383-390 ◽  
Author(s):  
Marion Merklein ◽  
Uwe Vogt

Tailored Heat Treated Blanks (THTB) are blanks that exhibit locally different strength specifically optimized for the succeeding forming process. The strength distribution is set by a local, short-term heat treatment modifying the mechanical properties of the material. Hence, THTB allow enhancing forming limits significantly leading to shorter and more robust manufacture process chains. In order to qualify the use of THTB under quasi series conditions, the interdependencies of the blank’s local heat treatment and the entire process chain of the car body manufacture have to be analyzed. In this respect, the impact of a short-term heat treatment on the mechanical properties of AA6181PX, a commonly used aluminum alloy in today’s car bodies, was studied. Also the influence of a short-term heat treatment on the coil lubricant, usually already applied by the material supplier, was given a closer look. Based on these experiments process restrictions for the application of THTB in an industrial automotive environment were derived and a process window for the THTB design was set up. In conclusion, strategies were defined how to enhance the found process boundaries leading to a more robust process window.



2007 ◽  
Vol 14 (01) ◽  
pp. 17-21 ◽  
Author(s):  
L. X. PANG ◽  
K. N. SUN ◽  
S. REN ◽  
J. Q. BI ◽  
R. H. FAN

Based on Pauling's nature of chemical bond, the valence electron structures of TiN and FeAl have been constructed, and the relative electron density differences (REDD) between the low index plane of TiN and FeAl , respectively, have been calculated. [110] FeAl //[110] TiN crystallography orientation has been set up from the minimization of the electron density difference across the interface. From the viewpoint of improving the mechanical properties of composites, the formation of such structures must been engineered in the fabrication processing.



2015 ◽  
Vol 651-653 ◽  
pp. 1472-1479 ◽  
Author(s):  
Gianluca D'Urso ◽  
Claudio Giardini

A study was carried out to evaluate how the Friction Stir Spot Welding (FSSW) process parameters affect the temperature distribution in the welding region, the welding forces and the mechanical properties of the joints. An experimental campaign was performed by means of a CNC machine tool and FSSW lap joints on both AA6060 and AA7050 aluminum alloy plates were obtained. Some thermocouples were inserted into the samples to measure the temperatures during FSSW. A set of tests was carried out by varying the process parameters, namely rotational speed, axial feed rate and plunging depth. Axial welding forces were measured during the execution of the experiments by means of a piezoelectric load cell. The mechanical properties of the joints were assessed by executing shear tests on the specimens. A comparison between the quality of the joints obtained on the two materials and a correlation between process parameters and joints properties was found. A FEM model for the simulation of the process was set up using the commercial code Deform 2D. The peculiarity of this model is a 2D approach used for the simulation of a 3D problem, in order to guarantee a very simple and practical model able to achieve results in a very short time. This solution was achieved, based on a specific external routine for the calculation of the developed thermal energy due to the friction between tool and workpiece. The collected experimental data were finally used to validate the model.



This paper aimed to investigate the mechanical characteristics of HSC of M60 concrete adding 25% of fly ash to cement and sand and percentage variations of silica fumes 0%,5% and 10% to cement with varying sizes of 10mm,6mm,2mm and powder of granite aggregate with w/c of 0.32. Specimens are tested for compressive strength using 10cm X 10cmX10cm cubes for 7,14,28 days flexural strength was determined by using 10cmX10cmX50cm beam specimens at 28 days and 15cm diameter and 30cm height cylinder specimens at 28 days using super plasticizers of conplast 430 as a water reducing agent. In this paper the experimental set up is made to study the mechanical properties of HSC with and without coarse aggregate with varying sizes as 10mm, 6mm, 2mm and powder. Similarly, the effect of silica fume on HSC by varying its percentages as 0%, 5% and 10% in the mix studied. For all mixes 25% extra fly ash has been added for cement and sand.



2021 ◽  
Vol 1016 ◽  
pp. 957-963
Author(s):  
Marie Moses ◽  
Madlen Ullmann ◽  
Rudolf Kawalla ◽  
Ulrich Prahl

Since 2018, the institute of metal forming has been studying the novel twin-roll casting (TRC) of magnesium wire at the pilot research plant set up specifically for this purpose. Light microscopic and scanning electronic investigations were carried out within this work and show the unique microstructure of twin-roll cast AZ31 magnesium alloy with grain sizes of about 10 μm ± 4 μm in centre and 39 μm ± 26 μm near the surface of the sample. By means of a short heat treatment (460 °C/15 min), segregations can be dissolved and grain size changes in centre to 19 μm ± 12 μm (increase) and near the surface to 12 μm ± 7 μm (decrease). Further, the mechanical properties of the twin-roll cast and heat-treated wire were analysed by tensile testing at room temperature. By heat treatment, the total elongation could be increased by a third whereas the strength decreases slightly. In heat-treated state, no preferred orientation is evident. In addition to the twin-roll cast and the heat-treated condition, the rolled state was analysed. For this purpose, the twin-roll cast wire was hot rolled using an oval-square calibration. After hot rolling, a dynamic recrystallization and grain refinement of the twin-roll cast wire could be achieved. It can be seen, that an increase in strength as well as in total elongation occur after wire rolling. Beside this, a rolling texture is evident.



2014 ◽  
Vol 60 (Special Issue) ◽  
pp. S66-S69 ◽  
Author(s):  
V. Malý ◽  
M. Kučera

This paper presents the mechanical properties of soil. In order to determine the properties of soil under laboratory conditions, a special measuring device was constructed, viz. a bevameter. Two types of soil with different levels of moisture were examined and their mechanical properties were determined. Measurements were taken of non-compressed soil. A measuring network was set up, consisting of measuring and recording devices. In the course of measuring, the force and penetration depth of the pressing plate were recorded simultaneously. Three different diameters of pressing plate were used, namely 38, 50 and 70 mm. The pressure on the contact area was calculated after completion of the measurements, and the relationships between pressure and penetration depth were presented graphically.



2015 ◽  
Vol 651-653 ◽  
pp. 225-230 ◽  
Author(s):  
Antonino Ducato ◽  
Gianluca Buffa ◽  
Antonello Astarita ◽  
Antonino Squillace ◽  
Livan Fratini ◽  
...  

Titanium forging has been encountering a growing interest in the scientific and industrial communities because of the distinct advantages it provides with respect to machining, in terms of both mechanical properties of the product and material waste, thus significantly reducing the Buy to Fly ratio. In the paper, a numerical FE model, based on a tri-coupled approach and able to predict the microstructural evolutions of the workpiece during the process, is developed and set up. Calculated results are compared to experiments for a few industrial case studies. The final phases distribution in the forged parts is experimentally measured and compared to the FE model output finding satisfying overlapping.



2014 ◽  
Vol 633-634 ◽  
pp. 391-395
Author(s):  
Wen Guang Liu ◽  
Cheng Yan

According to the Hypersonic Vehicle harsh environment, impacts of temperature on the mechanical properties for functionally gradient materials are studied. A power-law distribution of material is applied between the two pure materials; a material property model of FGMs is built. Several temperature conditions are set up and the results are obtained in the end through numerical analysis. It can be shown that the material properties of FGMs plate are temperature-dependent and vary along the thickness in terms of volume fractions of constituents.



Author(s):  
Renate W. Boekhoven ◽  
Richard G. P. Lopata ◽  
Marcel C. M. Rutten ◽  
Marc R. H. M. van Sambeek ◽  
Frans N. van de Vosse

Carotid endarterectomy is the procedure of choice in patients with a recent symptomatic stenosis of 70–99%. Currently, the selection of candidates eligible for carotid endarterectomy is based on stenosis size only. However, the treatment is only beneficial for patients with unstable plaques, which comprises only 16% of the patient population [1]. Hence, identifying plaque stability at an early stage would permit timely intervention, while substantially reducing overtreatment of stable plaques. The objective of this study is to distinguish between stable and unstable carotid atherosclerotic plaques by determining the plaque geometry, the plaque composition and the mechanical properties of plaque components in three dimensions (3D). Mechanical properties from healthy vessels were assessed earlier by van den Broek et al. [2] using ultrasound (US) imaging. They obtained a dynamic dataset in 2D + t. When blood pressure and vessel wall movement are known, mechanical properties can be extracted from these data using a constitutive model. However, atherosclerotic plaques are mostly asymmetric, and present calcifications will cause unfavorable acoustic shadowing when using US. In this study, the focus is on the assessment of plaque geometry, from in vitro echo-CT data, overcoming the aforementioned problems. In an experimental set-up (Fig. 1) both healthy and endarterectomy specimens were mounted, and exposed to physiological intraluminal pressures. Echo-CT was used to image the arterial segments in 3D+t. Automated geometry assessment of the arterial segments will be demonstrated and validated using microCT (μCT).



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