It appears you have multiple variables in your workspace with names such as U_01, U_02, ... U_60 and you want to make more of these using T. There is a way to construct a loop to process these names using the "eval" function, but as you can already see it is a real pain to deal with variables such as this in your code. The best advice I can give you is to abandon this approach and use cell or struct or multi-dimensional variables instead. E.g., see this link:
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