This is the 11792nd most frequent Russian word.
закрепились
"Secured," "established," or "firmly fixed."
Here, 'закрепились' implies that the warm memories have taken a firm place emotionally, indicating mental or emotional establishment.
В наших сердцах закрепились тёплые воспоминания о лете.
In our hearts, warm memories of summer have become entrenched.
In this sentence, 'закрепились' refers to the new rules being firmly established or adopted within the group.
Закрепились новые правила в рабочем коллективе.
The new rules have taken hold within the work team.
Here, 'закрепились' denotes the physical securing or fastening of the metal posts.