That is one big problem. I have a Jack Russell who is a strong chewer too. We gave him a rubber kong!!! That is pretty indestructable. They have several different types. Also, we gave Sparky a cloth bone. It is made entirely of cloth. He cas shred it but there is nothing there that will get lodged in his intestines. The nyla bones usually work pretty well too (for us, anyway) Those usually shredd is very small bits so you don't have to worry about those either.
Sparky is a really strong jawed dog. He can hold on to something and not let go, not even if you pick him up off the floor with it. We do not give him stuffed toys or things like that. They don't last 1o minutes with him.
You can try one of those kongs...they have them at pet stores. As an added bonus, you can put peanut butter in some of them so they will lick it. Helps relieve cage anxiety when you have to work. Sparky knows he is getting peanut butter when we leave and he loves it.