I am pretty sure you mean: "In the research referred to above, springback and sectional deformation were studied separately but they should be studied together [ ... and in this paper I report on experiments on their combined effect. ]"

I'll just ask a few questions and give a couple of suggestions - I've read the comments on Ben's answer, and unfortunately the whole sentence makes very little sense. Perhaps it's better to write it as simple sentences first, then shape it into the sentence you want. When you wrote "unilaterally", did you actually mean "either"? Perhaps "independently" might work, but be careful where you place it in the sentence. The verb "ignore" also seems out of place (and in the wrong verb form anyway), so you might want to re-think that. I'm not sure why "should" is in the sentence, and the verb "control" is either unclear or misused. We can't tell without context. There are a couple of other phrasing problems, and I think you should be able to work these out. It's not difficult grammar. At least you can use "the two" to refer to the separate issues of springback and sectional deformation. You could consider hiring a proofreader to correct your whole text - a research paper in poor English is very embarrassing to look at.

Don't worry about it. The sentence as a whole makes very little sense. Find something better to read.

Don't even understand what it's trying to say.

Hi: The meaning is simple. There are two subjects, combined with a predicate. "The above research unilaterally studied springback or sectional deformation, while ignored the two should be controlled together". The 2 subjects are: (a) springback (which is flexibility or plasticity) (b) sectional deformation (changes to the material caused by stress) These 2 subjects constitute "the two". Both of these need to be "controlled".