John F. Carney

Energy absorbing capacities of braced metal tubes

Abstract The collapse and energy dissipation characteristics of metal tubes braced with tension members are considered experimentally and load bounding techniques are employed to estimate collapse loads of such tubes. The results are applied in the full scale crash testing of a vehicle impact attenuation device composed of clusters of steel tubes and subjected to high speed roadway collisions.

Initial collapse of braced elliptical tubes under lateral compression

The initial collapse behavior of elliptical tubes subjected to lateral compression is investigated. Both unbraced and braced tubes are analysed, and the main factors which affect the initial collapse behavior are discussed and interpreted. Lower and upper bound theorems are applied to bracket the collapse load in a direct manner. The initial collapse loads for braced circular tubes, obtained as a special case of elliptical tubes, are compared to previous research results. The results and concepts presented herein can be useful in the development of design criteria for energy dissipating devices. Elliptical shapes, when loaded parallel to their major axes, can have an advantage over their circular counterparts in that they possess larger collapse strokes and an increased energy dissipation potential per unit mass.

Crushing analysis of braced metal rings using the equivalent structure technique

Abstract This paper presents a development of the equivalent structure technique to account for some of the effects of strain-hardening in structures undergoing plastic bending. The lateral compression of symmetrically deforming braced rings is analysed and the results compared with corresponding experimental data. The effects of strain-hardening on the analytical results both in the small deformation post-collapse regime and at large deformations prior to the onset of unstable deformations are discussed.

Passenger Train Crashworthiness—Secondary Collisions

Secondary collisions in passenger train crashes are considered and a companion paper dealing with primary collisions is followed up. The effects of crash pulse magnitude and duration, occupant flail distance, and the nature of the impacted surface are considered. The constitutive relationship for a Hybrid III dummy head satisfying the peak acceleration requirements of FMVSS208 is developed and used with the crash victim simulator MADYMO to investigate the impact response of train passengers seated in a unidirectional layout. It is shown that the design of the coach shell and the interior have to be integrated to obtain train designs that will minimize occupant injuries in the event of train collisions.

An experimental-modal computational technique to find dynamic stresses

Abstract It is shown how the dynamic stresses in a structure can be obtained from measured acceleration data in conjunction with computer calculations of the normal modes of the structure. The proposed technique is demonstrated and the treatment of experimental results is discussed.

NCHRP REPORT 350 CRASH TEST RESULTS FOR CONNECTICUT TRUCK-MOUNTED ATTENUATOR

The results of four full-scale crash tests performed on the Connecticut Truck Mounted Attenuator (CTMA) are summarized. The tests were conducted in accordance with the guidelines of NCHRP Report 350 for Test Level 2 devices. NCHRP Report 350 specifies two required and two optional tests. The four crash tests passed all requirements of NCHRP Report 350. No repeat tests were required, and the results were uniformly excellent. The successful CTMA test series is the first of several NCHRP Report 350 test programs that are anticipated to gain compliance for various impact attenuation systems designed and developed in Connecticut.

ENERGY DISSIPATION PROPERTIES OF LATERALLY CRUSHED TUBES AND TUBULAR CLUSTERS

This paper describes the energy dissipation characteristics of braced and unbraced tubes and tubular clusters when subjected to quasi-static and impact loadings causing large deformations. The effects of strain rate, stress waves and collapse mode on the impact response and energy dissipation characteristics are described and results of full-scale crash tests for the crash cushion application are shown. The large- scale deformation of metallic tubes is shown to be an effective method for dissipating the energy associated with an impact event. Such systems have a life saving potential when employed in safety applications where kinetic energy must be dissipated in a controlled manner such that decelerations remian within allowable limits. For the covering abstract see IRRD 863693.