---
title: "J.U. Brackbill"
type: "entity"
entity_kind: "person"
status: "hub"
canonical_name: "J.U. Brackbill"
aliases: ["Jeremiah Brackbill","Brackbill"]
first_seen: "2026-08-21T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["FLIP (fluid-implicit particle method)","Francis H. Harlow","Material Point Method","Los Alamos National Laboratory","particle-in-cell method"]
seek_code_commit: "17d9798"
---


Los Alamos National Laboratory physicist who, with H.M. Ruppel, developed FLIP (the
"fluid-implicit particle" method) in 1986 — a "full-particle" extension of
[[entity-francis-harlow|Francis Harlow]]'s particle-in-cell method
([[claim-pic-method-born-at-los-alamos-for-hydrodynamics]]). Matters to this vault as
the direct methodological predecessor both Material Point Method founding papers
name and repeatedly credit ("a procedure initiated by Brackbill and Ruppel") when
Sulsky, Chen, and Schreyer reformulated PIC/FLIP into MPM for Sandia-funded solid
mechanics work
([[claim-mpm-1994-paper-acknowledges-sandia-and-nsf-cofunding]]). Brackbill's own name
also appears on the Sandia report's Los Alamos distribution list, placing him as an
intended reader of the paper that built on his method.

## References
- [[claim-pic-method-born-at-los-alamos-for-hydrodynamics]]
- [[claim-material-point-method-1993-sandia-funded-penetration-mechanics]]
- [[claim-mpm-1994-paper-acknowledges-sandia-and-nsf-cofunding]]
- Captures: 10-inbox/raw/2026-08-21-was-the-material-point-method-actually-developed-for.md