Ramp test

An example of a rig which tests one property as a function of different conditions is the ramp test used to measure friction of flooring. An operator walks on a ramp the angle of which can be varied. The angle at which he slips is related to the coefficient of friction and can be measured for different footwear, or surface conditions, or treatments. 

Standard mixing conditions were to melt blend the samples at 300 C for five minutes at a rotor speed of 40 RPM. The effect of mixing history on the structure of the LCP/LCP blends has not been investigated in the present work. Such a study has been reported by Mehta and Baird (i ).The samples were, then, given two minutes at 5 RPM followed by programming the rotor speed to 100 RPM in a two minute period. The speed is, then, instantaneously lowered back down to 5 RPM in two minutes. This is followed by two minutes at 5 RPM to determine whether the ramp test has affected the sample i n any way. 

Fig. 9.9 Evolution of the friction coefficient and wear rates of disks lubricated by PEG with time during a frequency ramp test from 10 to 30 Hz for (a) PEG and (b) 2% Cj CmjimljlNTfj), (c) 2% Cj (mjim)j(PFg)j and (d) 2% C, (mjim)2(BF 2 at room temperature (stroke 1 mm, load 100 N) (Reproduced from Ref. [63] with kind permission of The American Chemical Society)...

Dynamic torsional shear experiments were conducted on a Rheometric Scientific ARES rheometer. The samples were cut 6.35 cm in length strips, 0.30 cm thick. The single frequency temperature ramp test was taken at 1 Hz from -100°C to 150°C at 2°C/min in the linear strain regime (0.01 to 2.00%). 

In view of the later experiments shown in Table 5 and Fig. 9 conducted by varying exposure time for Oil 780 (in which the full content of volatilizable phosphoms was delivered to the special Noack collector in less than 10 min), it is more likely that there is a difference in the path of phosphoms decomposition. That is, for Oil 780, the difference in oil volatility increases with and without extended ramping time - about 13 % - for the longer ramping test is considerably less than the 125 % increase in volatilized phosphoms. This preliminary finding emphasized the value of investigation using P NMR spectrometry to determine what differences were present. 

DIN 51097 92. Testing of floor coverings Determination of anti-slip properties Wet-loaded barefoot areas walking method - Ramp test. 

DIN 51130 92. Testing of floor coverings IX-lerminalion of anti-slip properlie.s W orkrooms and work areas with increased risk of slip Walking method Ramp test. 

Figure 19.11 Stress ramp test for CNT-grease containing 12.0 wt% SWNT. The grease was subjected to a stress range of 700-850 Pa. (Reproduced with kind permission from NLGI. Copyright (2010) NLGI)...

Similarly to the shear stress ramp tests, the yield stress tests produced results which suggest particle-particle interactions in the grease structure. The yield results are also similar to that of polymer suspensions [38]. 

Figure 5.17 DMA temperature ramp test results of the three samples...

Another important testing method used to determine the electrical service life of electric insulation materials is dielectric strength. Here, we distinguish between two types of alternating stress investigations, the short-time-test according to lEC 243, often referred to as the ramp-test , and the step-by-step tesr, often... 

Figure 27.1 Cell self-healing rate during forced thermal ramp test of Li-ion Gen 2 lithium-ion chemistry anode = MCMB electrolyte =1.2 M LiPFe In EC PC DMC I cathode = LiNio.gCoo.os AI0.05O2 I separator = Celgard 2325 trilayer (from Ref [15]).

Figure 6.5 illustrates similar test results for the doubly interrupted ramp test plotted stress vs strain. Again the same behavior of rejoining the original constant rate response is shown and also that the errors of linear theory grow with each cycle. 

As can be seen above, the equilibrium technique, gives a single line of data points in contrast to the hysteresis loops from traditional ramping techniques. While equilibrium flow may take a long time, it is certainly better to get the data in a usable form than to repeat ramp tests and try to estimate the steady state data. 

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