美國(FMI)Foundation Mechanics Inc www.jilsfwd.com
1969年，F(xiàn)oundation Mechanics Inc(FMI)公司成立于美國加州，為Wyle實驗室的下屬機構。而Wyle是最近50年來航空與原子能工業(yè)測試與測試設備設計領域的行業(yè)領導者。目前，F(xiàn)MI公司已是私有的設備制造供應商，是專門致力于設計和制造路面動態(tài)檢測系統(tǒng)的著名供應商。在1970年出品了第一件路面檢測設備“Road Rater”道路評價系統(tǒng)，隨后在1972年出品了“Pavement Profiler”路面斷面儀，1987年開始生產(chǎn)JILS FWD落錘彎沉儀。
今天，F(xiàn)MI以JILS FWD而聞名世界，為全球用戶設計并制造動態(tài)路面承載系統(tǒng)。產(chǎn)品早已獲得優(yōu)良聲譽，具有優(yōu)越的性能，精確、可靠。如今，用戶已遍布美國各州、大小城市、甚至私有機構和其他各國。FMI公司同時也為客戶專門設計制造“用戶定義化”的路面和地基的測試系統(tǒng)設備，并為醫(yī)用及航空領域設計和制造動態(tài)承載系統(tǒng)。

In 1969, Foundation Mechanics, Inc. was incorporated in the state of California as a subsidiary of Wyle Laboratories. Wyle Laboratories had been a leader in testing and in the design of testing systems for the aerospace and nuclear industry for nearly fifty years. Foundation Mechanics, Inc. (FMI) is now privately held and operates from its world headquarters near the Los Angeles airport in El Segundo, California. FMI has been designing and building dynamic pavement testing systems since its inception. The Road Rater™ was built in 1970, followed by the Pavement Profiler in 1972, and then the JILS-FWD in 1987. 

Today, FMI, now known and marketed as JILS, produces dynamic custom-designed pavement and foundation loading and testing systems for state, county, and city departments, private agencies, medical and aerospace applications, and numerous other entities world-wide. All JILS systems are well supported and have earned a strong reputation for performance, accuracy and reliability. 

A falling weight deflectometer, or FWD for short, is a testing device used by civil engineers to evaluate the physical properties of a stretch of pavement. This could include (but is not limited to) highways, local roads, and airport runways. The machine is usually contained within a trailer that is driven to a location by another vehicle. At a pre-designated change in distance, the FWD device is deployed. A metal plate on the device is set up to strike the pavement at a given force, and sensors are placed around the plate and in a straight line radiating from the plate. These sensors record the deflections in the pavement (analogous to ripples in a pond) induced by the falling weight, hence the name "falling weight deflectometer".
This device has several practical purposes in determining the properties of pavement. For one, voids or empty spaces can be detected underneath the roadway. Joint testing determines how two abutting slabs of concrete or asphalt are fitting against one another. Other statical analyses determine the general strength of the structure, and can even predict what materials and in what combination were used to build the pavement if such information is unknown.