The phrase "a weak part of" is correct and usable in written English.
It can be used to describe a specific aspect or element of something that is not strong or effective.
Example: "The report highlighted a weak part of the argument that needed further evidence to support it."
Alternatives: "a vulnerable aspect of" or "a flawed component of".
"The talent pool at Cathay has been a weak part of the group," Lee adds.
The results showed that a reinforcement of the interfacial transition zone (ITZ), a weak part of the concrete, by coating the surface of the original coarse aggregate with surface-modification material, can help suppress the occurrence of microcracks and improve the mechanical performance of the aggregate.
To put it bluntly, the feet separate because the ankle is a weak part of the body.
A weaker part of the systems then stalls overhead, keeping a chance of scattered showers in the forecast through at least the first half of the weekend.
By his own admission, scoring was a weaker part of his game in his first few seasons at Arsenal; wasteful finishing also being symptomatic of the larger problem surrounding Arsenal in the 2005 06 and 2006 07 seasons.
A particularly weak part of the skull that is vulnerable to damage causing extradural haematoma is the pterion, deep in which lies the middle meningeal artery, which is easily damaged in fractures of the pterion.
As is the case in other low-income countries, supply chain management is an especially weak part of the national health system.
Tenors are often the weak part of a chorus, but here they may have been the strongest.
A juggernaut wears a suit that is built for high damage, but we all know that the head is the weak part of a human.
This is the weak part of our value chain.
A man in the UK tried to kill three women because he was a virgin and thought of them "as a more weaker part of the human breed".
