Brake dynamometer model predicting brake torque variation due to disc thickness variation

Author(s):  
Jaeyoung Kang ◽  
Sungjin Choi
Author(s):  
Helena Jacobsson

Abstract Brake judder can be explained as a dynamical amplification of brake torque variation (BTV) when passing through a critical speed of a vehicle. The BTV arises owing to different geometrical defects e.g. disc thickness variation (DTV), disc runout and dynamical effects. DTV is usually the most important source of these fluctuations. Measurements have been made on a passenger car with heavy DTV on one of its front brakes. The eigen frequency of the wheel suspension was found to be 14 Hz, corresponding to a first order critical speed of 95 km/h. These measurements qualitatively verify the brake model with a maximum caliper vibration amplitude close to 100 km/h followed by a slowly decreasing amplitude.


2014 ◽  
Vol 66 (3) ◽  
Author(s):  
M. K. Abdul Hamid ◽  
A. M. Kaulan ◽  
A. R. Abu Bakar ◽  
W. B. Wan Nik

This work examined the frictional force induced by the disc brake when the disc brake gets corroded. The corrosion process was carried out on two types of disc brake labelled disc A and disc B where both disc brakes were made from gray cast iron but having different design. Both discs were burnished with two types of friction materials labelled P-1 and P-2 before they were exposed to the open air environment to simulate the disc corrosion for a parked vehicle. The change in brake torque and friction coefficient was analyzed using a single-end brake dynamometer. The results showed that the burnishing effect of the friction material has significant effect on the formation of oxide layer. Oxide layer formed on disc burnished with friction material P-2 was more concentrated and thicker compared to the disc burnished with friction material P-1. Also, the results showed that brake torque and friction coefficient were closely dependent on the removal of the oxide layer and by the friction film on the burnished disc surface while applying the brake. Thus the composition of friction materials is critical to affect the formation of the oxide layer on the disc and consequently, the performance of the frictional force of disc brake system.


Author(s):  
G. Botton ◽  
G. L’Espérance ◽  
M.D. Ball ◽  
C.E. Gallerneault

The recently developed parallel electron energy loss spectrometers (PEELS) have led to a significant reduction in spectrum acquisition time making EELS more useful in many applications in material science. Dwell times as short as 50 msec per spectrum with a PEELS coupled to a scanning transmission electron microscope (STEM), can make quantitative EEL images accessible. These images would present distribution of elements with the high spatial resolution inherent to EELS. The aim of this paper is to briefly investigate the effect of acquisition time per pixel on the signal to noise ratio (SNR), the effect of thickness variation and crystallography and finally the energy stability of spectra when acquired in the scanning mode during long periods of time.The configuration of the imaging system is the following: a Gatan PEELS is coupled to a CM30 (TEM/STEM) electron microscope, the control of the spectrometer and microscope is performed through a LINK AN10-85S MCA which is interfaced to a IBM RT 125 (running under AIX) via a DR11W line.


Author(s):  
Suresh Kulkarni ◽  
Ranjit P. ◽  
Nikunj Patel ◽  
Someshwara B. ◽  
Ramesh B. ◽  
...  

The present investigation deals with the formulation of fast disintegrating tablets of Meloxicam that disintegrate in the oral cavity upon contact with saliva and there by improve therapeutic efficacy. Meloxicam is a newer selective COX-1 inhibitor. The tablets were prepared by wet granulation procedure. The influence of superdisintegrants, crosspovidone, croscaremellose sodium on disintegration time, wetting time and water absorption ratio were studied. Tablets were evaluated for weight and thickness variation, disintegration time, drug content, in vitro dissolution, wetting time and water absorption ratio. The in vitro disintegration time of the best fast disintegrating tablets was found to be 18 sec. Tablets containing crospovidone exhibit quick disintegration time than tablets containing croscaremellose sodium. The fast disintegrating tablets of Meloxicam with shorter disintegration time, acceptable taste and sufficient hardness could be prepared using crospovidone and other excipients at optimum concentration.


2020 ◽  
pp. 38-45
Author(s):  
В.В. Павлюченко ◽  
Е.С. Дорошевич

Based on the developed methods of hysteresis interference, the calculated dependences U(x) of the electric voltage taken from the magnetic field transducer on the x coordinate were obtained. A magnetic carrier with an arctangent characteristic was exposed to a series of bipolar pulses of the magnetic field of a linear inductor of one, two, three, four, five and fifteen pulses. An algorithm is presented for the sequence of changes in the magnitude of the total strength of the magnetic field pulses on the surface of an aluminum plate, which provides the same amplitude of hysteresis oscillations of the electric voltage and makes it possible to obtain a linear difference dependence U(x) for wedge-shaped and flat aluminum samples. The results obtained make it possible to increase the accuracy and efficiency of control of the thickness of the object and its thickness variation in the given directions, as well as the defects of the object.


Author(s):  
Ritesh Ray Chaudhuri ◽  
William Simpson ◽  
Daniel Fedor ◽  
Prabhakar Bharatan ◽  
Joseph Thompson ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Azza Ahmed ◽  
Amani Baldo ◽  
A. Sulieman ◽  
Hind Mirghani ◽  
Fouad A. Abolaban ◽  
...  

AbstractThis work aimed to investigate the effect of different shim techniques, voxel sizes, and repetition time (TR) on using theT2 and T2* sequences to determine their optimum settings to investigate the quantification of iron in transfused dependent sickle cell patients. The effect of each of these parameters was investigated on phantoms of different Gadolinium (Gd) concentrations, on 10 volunteers and 25 patients using a1 5T MRI Philips scanner. No significant difference between the three shim techniques was noticed in either T2 or T2* sequence measurements. Pixel sizes of 1 × 1 and 2 × 2 mm provided optimum results for T2 measurements. At 1 × 1 mm pixel size the T2* measurements experienced less error in measurements than the size of 2.5 × 2.5 mm used in the literature. Even though the slice thickness variation did not provide any changes in T2 measurements, the 12 mm provided optimum T2* measurements. TR variation did not yield significant changes on either T2 or T2* measurements. These results indicate that both T2 and T2* sequences can be further improved by providing more reliable measurements and reducing acquisition time.


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