Frank Otremba

Analysis of the capsizing of a tanker in the Rhine river

A dynamic simulation model for a tanker ship along the Rhine River has been proposed, based on a simplified computational scheme, involving a two-degree-of-freedom roll plane multibody system, subjected to lateral accelerations estimated on the basis of measured data. The resulting equations of motion are solved through the transition matrix approach. The results suggest that many contributing factors were involved in the capsizing of the ship, including the relatively high speed of the river water and the meandering path of the infrastructure, further affected by dynamic effects derived from the behavior of the payload and from the steering maneuvers performed.

Fire Testing of Total Containment Pressure Vessels

In North America certain hazardous materials are transported in rail tank cars that must be able to survive an engulfing liquid hydrocarbon pool fire for 100 minutes without rupture. To meet this requirement these tanks are normally equipped with pressure relief valves (PRV) and some form of thermal insulation or thermal protection (TP). These tanks sometimes have non-accident releases (NAR) due to unwanted activation of, or leakage from the pressure relief valves (PRV). These NARs are a nuisance for Industry and for this reason, the industry now wants to remove the PRVs from certain tanks. This is known as total containment and is common practice in Europe. However, Europe does not have a 100 minute fire survival requirement. This paper is about a series of fire tests of 1/3 rd linear scale US DOT 111 Tanks cars. The 2.4 m3 vessels were subjected to fully engulfing fires generated by liquid propane fueled burners.

Modeling of Vehicle-Cargo Interaction Under Different Environments

The safety of any transport system depends on a multitude of conditions, parameters and circumstances. In this regard, the interaction of the carried cargo with the carrying vehicle represents a factor influencing the overall safety of any transport. The effects of cargo on the vehicle have to do with the vibration or shifting of the cargo, affecting the lateral stability of the vehicles and the braking performance. Such interaction has been associated to road crashes and maritime vehicles capsizing. Simulation of cargo-vehicle interaction thus represents an interesting topic when a reduction in transport accidents is pursued. In this paper, the fundamentals principles for simulating the interaction of the liquid cargo and the carrying vehicle, is presented. In the case of a road transportation, the proposed simplified simulation methodologies, show good agreement with a full-scale test.

A testing rig to study vehicle-track interaction during turning

Preliminary data of accidents, pointing out about rail fracture potentials of sloshing cargoes. Testing rig, designed to characterize the effect of vehicle characteristics and infrastructure design, on the forces exerted on the rail. The corresponding mathematical model will be.

Fire protection systems for tanks made of GFRP

The application of lightweight materials for tanks for transportation appears promising. Besides saving weight and therefore transportation costs, new complex geometries that depart from common cylindrical shapes of steel tanks can be manufactured. For transportation of dangerous goods, fire and explosion safety must be maintained to prevent accidents with serious consequences. In this work the fire behavior of lightweight tanks made from glass fiber reinforced plastics (GFRP) with complex geometries is investigated. Pretests on intermediate scale GFRP plates are conducted to identify suitable fire protection systems and surface treatments for composite tanks. The fire resistance is shown to be improved by addition of fire protective coatings and integrated layers. Finally, a complex rectangular GFRP tank with a holding capacity of 1100 liters is fire protected with an intumescent fire coating. The tank is filled up to 80 % with water and burned under an engulfing fully developed fire. It was shown that the intumescent layer could expand before the decomposition of the resin occurred. Furthermore, the adhesion between tank surface and coating was maintained. The structure could withstand a fire for more than 20 min.

Experimental and Theoretical Modeling of Cargo Sloshing During Braking

Taking into account a multitude of experimental and theoretical studies reported in the literature, the braking efficiency of road tankers can be affected by the sloshing forces developed by the carried liquid during such maneuvers, as a result of the dynamic pressures exerted by the sloshing liquid on the vehicle containers walls, and of the shifting of the liquid center of gravity. However, such studies have not involved a full scale experiment. In this paper, a simplified model is proposed to study the effect of the sloshing dynamics on a road tanker braking efficiency. Results from this simplified approach, are compared with data from full scale testing, revealing that the simplified model is good to predict the maximum pressure that the sloshing liquid exerts on one of the vehicle chambers. The simplified model considers a straight truck and a pendulum analogy for the sloshing liquid, whose parameters are derived from a validated methodology to predict the sloshing frequency of the fluid within its container. Simulation of non-sloshing cargo further suggests that the stopping time can be increased by 7 % due to the sloshing cargo.Copyright

Rail Tank Car Total Containment Fire Testing: Results and Observations

The frequent incidences of Non-Accident Releases (NARs) of lading from tank cars have resulted in an increasing interest in transporting hazardous materials in total containment conditions (i.e., no pressure relief devices). However, the ability of tank cars to meet thermal protection requirements provided in the Code of Federal Regulations under conditions of total containment has not been established. The intent of this effort was to evaluate through a series of third-scale fire tests, the ability of tank cars to meet the thermal protection requirements under total containment conditions, with a particular focus on caustic ladings. A previous paper on this effort described the test design and planning effort associated with this research effort.A series of seven fire tests were conducted using third scale tanks. The test fires simulated fully engulfing, hydrocarbon fueled, pool fire conditions. The initial tests were conducted with water as a lading under jacketed and non-jacketed conditions and also with different fill levels (98% full or 50% full). Additionally, two tests were conducted with the caustic, Sodium Hydroxide as the lading, each test with a different fill level. In general, the tanks with water were allowed to fail or reach near-failure conditions, whereas, the tests with the caustic lading were not allowed to proceed near failure for safety reasons. This paper describes the results and observations from the fire tests, and discusses the various factors that affected the fire test performance of the test tanks.Review of results from the one-third scale tests, and subsequent scaling to full-scale suggest that a full-scale tank car filled with 50% NaOH solution is unlikely to meet the 100-minute survival requirement under conditions of total containment.Copyright

Rail Tank Car Total Containment Fire Testing: Planning and Test Development

Given the frequent incidences of Non-Accident Releases (NARs) of hazardous materials from tank cars, there in an increasing interest in transporting hazardous materials in total containment conditions (i.e., no pressure relief devices). However, the ability of tank cars to meet thermal protection requirements provided in the Code of Federal Regulations under conditions of total containment has not been established. Also, the modeling tool commonly used by industry to evaluate thermal protection, AFFTAC, has not been validated under these conditions. The intent of this effort was to evaluate through a series of third-scale fire tests, the ability of tank cars to meet the thermal protection requirements under total containment conditions, and also, to validate AFFTAC for such conditions.This paper describes the test design and planning effort associated with this research, including the design and evaluation of a fire test setup to simulate a credible, fully engulfing, pool fire that is consistent and repeatable, and the design and hydro-static testing of a third-scale tank specimen. The fire design includes controls on the spatial distribution and temperature variation of the flame temperature, the heat flux, and the radiative balance, to best reflect large liquid hydrocarbon pool fire conditions that may be experienced during derailment scenarios.Copyright

Consistency Between Analytical and Finite Element Predictions for Safety of Cylindrical Pressure Vessels at Higher Temperatures

Abstract The prediction of the plastic collapse load of cylindrical pressure vessels is very often made by using expensive Finite Element computations. The calculation of the collapse load requires an elastic-plastic material model and the consideration of non-linear geometry effects. The plastic collapse load causes overall structural instability and cannot be determined directly from a Finite Element analysis. In the present paper the plastic collapse load for a cylindrical pressure vessel is determined by an analytical method based on a linear elastic perfectly plastic material model. When plasticity occurs the material is considered to be incompressible and the tensor of plastic strains to be parallel to the stress deviator tensor. In this case the finite stress-strain relationships of Henkel can be used for calculating the pressure for which plastic flow occurs. The analytical results are completely confirmed by Finite Element predictions.

Comparison Between Analytical and Finite Element Calculation for Pressurized Container

The prediction of the plastic collapse load of cylindrical pressure vessels is very often made by using expensive Finite Element Computations. The calculation of the collapse load requires an elastic-plastic material model and the consideration of non-linear geometry effects. The plastic collapse load causes overalls structural instability and cannot be determined directly from a finite element analysis. The ASME (2007) code recommends that the collapse load should be the load for which the numerical solution does not converge. This load can be only determined approximately if a expensive nonlinear analysis consisting of a very large number of sub steps is done. The last load sub step leading to a convergent solution will be taken as the critical load for the structure. In the instability regime no standard finite element solution can be found because of the lack of convergence of the numerical procedure. Other methods for the calculation of the allowable pressure proposed by the ASME code are the elastic stress analysis and the limit load analysis. In the present paper the plastic collapse load for a cylindrical pressure vessel is determined by an analytical method based on a linear elastic perfectly plastic material model. When plasticity occurs the material is considered as incompressible and the tensor of plastic strains is parallel to the stress deviator tensor. In that case the finite stress-strain relationships of Henkel can be used for calculating the pressure for which plastic flow occurs at the inside of the vessel wall or in the case of full plasticity in the wall. The analytical results are fully confirmed by finite element predictions both for axisymmetric and high costs three dimensional models. The analytical model can be used for fast predictions of the allowable load for the design of a large variety of pressure vessels under safety considerations. The accuracy of the predicted collapse load largely depends on the quality of the temperature dependent wall material data used both in the analytical and numerical calculations.Copyright