Richard M. Christensen, expert on the mechanics of materials, has died

Richard Christensen, a research professor emeritus of aeronautics and astronautics and of mechanical engineering at Stanford University, and a noted expert in the field of the mechanics of materials, died April 12, 2024. He was 91.

Christensen’s long and diverse career included positions in industry, national laboratories, and academia. His academic career began at the University of California, Berkeley, where he taught until 1967 before joining Shell Oil Company as a staff research engineer. He remained with Shell for seven years, including a two-year stint with Royal Dutch Shell, during which time he and his family lived in the Netherlands, spending considerable time traveling around Europe. Returning to academia, Christensen accepted positions at the University of Houston and at Washington University in St. Louis before returning to California, where he once again joined the faculty at UC Berkeley and worked as a senior scientist at Lawrence Livermore National Laboratory. Christensen joined the UC Davis faculty as a member of the College of Engineering’s Department of Applied Science in 1988, remaining there until 1994. That year he accepted a position as professor (research) at Stanford University, which he held until his retirement as professor emeritus in 2007.

Christensen’s work focused on “failure criteria,” in particular the circumstances under which materials shift from safe states of stress to states of certain failure.

“He was an accomplished mathematician and came up with theories and mathematical methods to assess how advanced composite structures accumulate damage, how they respond to that damage, and how they eventually fail,” said Juan Alonso professor of aeronautics and astronautics at Stanford. “These materials revolutionized aircraft by making them as hard as steel but significantly lighter, and able to sustain damage while still maintaining safety.

“Dick’s work reflected the quintessential elements of being a great engineer,” Alonso said. “It’s trying to figure out how much you can push materials to get the performance of a vehicle as high as possible without failing.”

Much of Christensen’s work is detailed at his own website, FailureCriteria.com. In addition to writing scores of journal articles, he was the author of three books: Theory of Viscoelasticity, Mechanics of Composite Materials, and The Theory of Materials Failure. Christensen was elected to the National Academy of Engineering in 1987 for his work in continuum mechanics. His many other awards and honors include the 1988 Worcester Reed Warner Gold Medal from the American Society of Mechanical Engineers (ASME) and, in 2006, ASME’s Nadai Medal, awarded in recognition of significant contributions and outstanding achievements that broaden the field of materials engineering.

“His books were groundbreaking, had a lot of influence, and are still widely used now,” said Brian Cantwell, professor emeritus at Stanford School of Engineering. “Anybody working in the field would have them on their shelf. Dick was very well known, highly respected, and at Stanford he played an incredibly valuable role as an intellectual leader. His opinions and thoughts at faculty meetings were always very cogent, and he was a tremendously thoughtful, affable person.”

Christensen and his wife, Kristy, especially enjoyed traveling to professional conferences around the world, where he loved connecting with far-flung colleagues, said daughter Lori Enright. He ran every day into his 60s, including participating in San Francisco’s Bay to Breakers race. He also loved skiing – especially at Jackson Hole, Wyoming – and hit the slopes into his 70s. He had a special soft spot for his 1960s burnt-orange Ford Mustang, which he loved to take to car shows.

Richard Monson Christensen was born July 3, 1932, in Idaho Falls, Idaho. He earned his bachelor’s degree in civil engineering at the University of Utah in 1955, and went on to earn his master’s and professional doctorate in engineering at Yale University in 1956 and 1961, respectively.

Christensen was predeceased by his wife, Kristy, and is survived by daughter Lori Enright and son Kurt Christensen, son-in-law Bill Enright, daughter-in-law Karen Christensen, and grandchildren Sonja, Ian, Cale, and Natalie Enright and Piper and Parker Christensen.