How do you constrain input delay for a multidimenionsal input vector?
There is a -regexp option for get_posts. Try:

set_input_delay -clock [get_clock clk] 5000 [get_ports -regexp data_x\[\d+\]\[\d+\]\[\d+\]]


You can get bus ports by their base name. Not sure it it works on multi-dimensional arrays. So this might also work:

set_input_delay -clock [get_clock clk] 5000 [get_ports data_x]