Hello,
One referee asked me a question about one of the papers. Could anybody explain this one for me? I never thought about it
The load cell of the Instron was 100KN which is very large. Depending on the maximum presented load during the analysis this might present measurement error since as a rule of thumb the maximum presented load should not be lower than 10% of the load cell value. Please add the dimensions of the specimen so that the error may be assessed and if the above are applicable to this case consider adding a paragraph to present limitations.
How can I answer?
The answer here need to be more specific to the experiment carried out and I guess the question asked is by some referee for your article.
In your experiment as described the load cell used is of 100kN. Generally, the load cell capacity is mentioned in the datasheet is in kg or kN. Let us consider the max capacity of load cell is in terms of force (kN). So if it is 100kN means you can apply maximum 100kN to get full signal output. Now in your case the load cell might be used below 10% of max value. Please note the accuracy of force measurement is highly dependent on the amount of force being measured to the max capacity. You need to include the accuracy of measurement as it may be poor at 10% or below. You can get the accuracy and other relevant information from the datasheet of load cell.
As far as experimentation is concerned it is advisable to use lower capacity of load cell if the application is limited to the low value of the actual full capacity. This would provide relatively better accuracy.
@P. K. Dubey
Thank you Mr Dubey. We could not do it again actually. Our samples are 150 mm length and 25 mm width with 2 mm thickness. By t he way we compare the samples together and therefore if there is any error they would be for all of them and hopefully this might help us to still compare.
I do not get the last part of his sentence
Please add the dimensions of the specimen so that the error may be assessed and if the above are applicable to this case consider adding a paragraph to present limitations.
what does this mean?
Actually the comments of the reviewer are completely related to the article and more precisely the novelty you claim in. So here it is difficult to judge the actual intention of the reviewer behind his comments. I also understand that you can not share the detail here due to its confidentiality. And I also strongly recommend not to share.
I guess the objective is to compare the samples with the help of load cell. Now if the dimensions of your sample are same up to certain degree of accuracy it can cancel the effect of error. But again the accuracy depends on many other factors such as measurement resolution becomes more dominant below 10%. So details of the entire system is necessary to comment further.
@P. K. Dubey
Thank you. The dimensions are same for sure. Would you please clarify what does this mean ? " measurement resolution becomes more dominant below 10%. "
I will explain the above statement with example. This is also related to the reviewer comment. Generally the output of any load cell is measured by the analog or digital meter or by some ADC. Let us consider that the load cell signal after suitable signal conditioning is monitored by 3&1/2 digit meter. In this situation the maximum output will be 1999. Suppose it is used for maximum 200 kN. So it can display maximum 199.9kN for full load. The minimum change in load it can detect is limited to 0.1kN. So the % change 0.05%.
Now consider the case where it is only used for 10% of full range that is 20kN. Here as the resolution still remains same now if considered in terms of % will be 0.5%. Which is 10 times poor than when utilised for full range. This can be achieved by using other load cell to have full range only up to 20kN.
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