Acoustical Society of America
Gold Medal Award - 1999

Henning E. von Gierke

HENNING E. VON GIERKE as born in Karlsruhe, Germany on 22 May 1917 into a family whose heritage includes scientists in the fields of medicine and jurisprudence. In the late 1930s he began studies of electrical engineering and acoustics at the Technical Universities in Karlsruhe and Munich, receiving a Diplom Ingenieur in 1943 and a Doktor of Engineering (Communications Engineering, Acoustics) in 1944 from the Technical University Karlsruhe. There, for his thesis, he studied pure tone sound radiation from gas jets under Professor Herman Backhaus, a great researcher on sound radiation from musical instruments and loudspeakers. After finishing his thesis he applied his knowledge of the physical instabilities of the gas jets to understanding the mechanisms that enable a human to whistle with results that many years later interested marine acousticians studying sounds of dolphins. His combined interest in physical principles governing mechanical processes and human responses formed the basis of his professional career in studying the interaction of acoustical, mechanical energy with the human organism. His work over more than five decades covers the transmission, action, and human perception of all types of mechanical energy from infrasound, vibration, impact, and blast through the audio spectrum to ultrasound in air as well as in tissue.

The outstanding results that he achieved in these five decades were due to a combination of several key qualities. Henning is a true teacher, who, through his quick focused and deeply probing questions, stimulates his associates to think and to think logically. His scientific curiosity, which accompanies him at all times, has led to the development of several patented devices and to the answers to many scientific questions. But the quality that has brought success to many of his endeavors is his remarkable ability to quickly find the central core of a complex issue, and then to energetically lead others in building solution bridges outward on a logical basis, using both experiment and theory in balance. To these qualities he adds both the realization that one of the most important responsibilities of scientists in our present society is to see that scientific results are applied in a correct and timely manner. He has had the energy, patience, and dedication to lead the development and adoption of national and international standards addressing human safety, health and well being with respect to noise, vibration, shock, and impact.

In 1947 Henning, together with several colleagues from the Helmholtz Institute, came to the United States to work for the Army Air Corps in the Bioacoustic Section of the Biophysics Branch of the Aero Medical Laboratory at Wright Field near Dayton, Ohio. In 1950 he married Hanlo Weil, the daughter of two noted artists. They have two children, Karin and Susanne, who were brought up in their home in Yellow Springs, Ohio. There, Henning is active in many civic organizations, and has also demonstrated his theatrical talents, for many years playing the leading role of star singer in Yellow Spring's annual medieval Christmas play.

His early years at Wright Field were dedicated to understanding the magnitude and effects of aircraft noise on humans. His research on intense aircraft noise exposures defined new data on human tolerance limits, noise-induced hearing loss, auditory pain, and hearing protection, all of which stand today. In 1957 he introduced with others the equal energy hypothesis as the time-intensity trade-off for the Air Force hearing conservation regulation. Many years later he chaired the International Standards Organization (ISO) working group which prepared and obtained consensus for the adoption of ISO 1999, which used the equal energy rule as the basis for determining the relationship between occupational noise exposure and the estimate of the resulting hearing impairment. To address the noise problems of residents near air bases, helped the ten-year development of a comprehensive procedure for prediction of aircraft noise exposure near airports, estimating community response, and land use planning for the Air Force, published in 1964. This methodology provided the basis for the procedures in use today. In the early 1970s, he chaired the Environmental Protection Agency task force charged with meeting the Congressional mandate to "identify levels of environmental noise requisite to protect public health and welfare with an adequate margin of safety." The findings in the task force's "Levels" and "Criteria" reports have provided the basis for non-occupational noise criteria in the United States for the last 25 years.

One of Henning's first research studies at Wright Field was to investigate the effects of high intensity ultrasound on humans. Although the press had speculated on an "ultrasonic sickness," the research soon demonstrated that there is no significant effect of airborne ultrasound on the hearing of humans, and that annoyance is eliminated by wearing hearing protectors. The results of measurements of the acoustic absorption of the skin produced questions that led to mechanical impedance measurements and fundamental studies of the physics of vibrations in human tissue. The results, understood only after analyzing the roles of transverse shear waves, compression waves, and surface waves in body tissues, enabled calculation of some of the unknown physical parameters of tissue. This whole body of information enabled Henning to develop among other things a lumped parameter model of the helmet–earmuff–earplug–ear system which is still in use. Several models of other aspects of the human mechanical system was developed which helped to explain and unify the results of vibration and impact experiments over the infrasonic and sonic frequency ranges accumulated over the years by researchers on both animals and humans. His work led to the development of human tolerance criteria for vibration and shock which were used as the basis for a comprehensive set of ISO safety and performance consensus standards for vibration exposure. His studies are documented in over 160 publications on noise exposure and its effects on biodynamics of human exposure to impact, crash and on vibration loads, on vestibular effects and protection against hazardous force environments.

Henning's laboratory grew from the Bioacoustics Section to a Branch which he headed and in 1956 expanded to a division which would be called the Biodynmamics and Bioengineering Division of the Armstrong Aerospace Medical Research Laboratory. He directed this division from 1956 to 1988 when he retired to become its technical advisor. Henning was an inspiring leader and teacher for its research scientists, and for top scientists from around the world who came to work in the laboratory with its unique facilities for periods of a few weeks to years.

From the 1950s on, Henning provided consultations to many organizations, including the Army on impulsive noise and blast, the Navy on underwater noise exposure, NASA on radiation of rocket noise and blast, the Navy on underwater noise exposure, NASA on radiation of rocket noise and the effects of noise, acceleration, and motion on astronauts, ground personnel, and communities, FAA on airport noise, EPA on the full range of environmental noise issues, and the automotive industry on noise and impact. He was Clinical Associate Professor, Department of Preventive Medicine, Ohio State University and is Clinical Professor, Department of Community Medicine, Wright State University.

Henning has been a member of the Acoustical Society of America for 45 years and a Fellow since 1956. He has been an active participant in several technical committees, organizer of many technical sessions, and author of numerous invited and contributed papers. He served on the Executive Council and on several administrative committees and was President in 1979–80. He has been the leader in the development of the Society's Standards Program, chairing the Committee on Bioacoustics and serving as the first ASA Standards Director. For many years he organized and led the United States delegation to the ISO TC/43 Technical Committee on Noise, and for 30 years he chaired the ISO TC/108 Subcommittee SC4 on human exposure to mechanical shock and vibration. He was a member and past Chairman of the National Research Council Committee on Hearing, Bioacoustics, and Biomechanics (CHABA) and was actively involved with several of its working groups. He is a member and past president of the International Commission on Biological effects of Noise, a member and past Chairman of the American National Standards Institute Acoustical Standards Management Board, a member of the Institute of Noise Control Engineering and the Aerospace Medical Association.

The honors and awards received by Henning clearly reflect his international stature and identify some of the organizations that he served so well. He is a fellow and past vice president of the Aerospace Medical Association and received its Eric Liljencrants and A. D. Tuttle Awards. He is an elected member of the National Academy of Engineering of the United States, the International Academy of Aviation and Space Medicine, and the International Academy of Astronautics. He received the Department of Defense Distinguished Service Civilian Service Award, and it's the Meritorious Executive Presidential Rank Award for outstanding government service, and in 1981 the Distinguished Executive Award by the President on the United States. He was awarded the Commander's Cross of the Order of Merit of the Federal Republic of Germany, the Acoustical Society of America Distinguished Service Citation and its Silver Medal in Noise, the H. R. Lesser Award by the American Society of Mechanical Engineers, and the Rayleigh Medal from the Institute of Acoustics, United Kingdom.

Kenneth M. Eldred