See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/305483415 Strength Analysis of Shipping Container Floor with Gooseneck Tunnel under Heavy Cargo Load Article in Solid State Phenomena · July 2016 DOI: 10.4028/www.scientific.net/SSP.252.81 CITATION READS 1 2,064 2 authors: Arkadiusz Rzeczycki Bogusz Wisnicki Maritime University of Szczecin Maritime University of Szczecin 2 PUBLICATIONS 1 CITATION 99 PUBLICATIONS 42 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Increasing operational effectiveness of complex technical systems by systematic development and implementation of innovations using novel materials and modifying the object’s structure View project All content following this page was uploaded by Bogusz Wisnicki on 06 September 2016. The user has requested enhancement of the downloaded file. Strength Analysis of Shipping Container Floor with Gooseneck Tunnel under Heavy Cargo Load Arkadiusz RZECZYCKI1, a* and Bogusz WIŚNICKI1,b 1 Maritime University Szczecin, Institute of Transport Engineering Henryka Pobożnego 11 Street, 70-507 Szczecin, Poland a a.rzeczycki@am.szczecin.pl, bb.wisnicki@am.szczecin.pl Keywords: Shipping container, gooseneck tunnel, heavy cargo, strength analysis, finite element method. Abstract. Currently, guidelines for safely loading shipping containers with heavy cargo in the gooseneck tunnel region do not exist. This work investigates the influence of the construction type of the gooseneck tunnel on the strength of the floor of the shipping container. The main objective is to develop guidelines for loading shipping containers with heavy cargo in the gooseneck tunnel region. This paper investigates strength of the floor using finite element method. The finite element analysis shows how the container's floor responds in the given loading scenarios. Introduction Shipping containers are most commonly used load units and can be utilized to transport any kind of cargo. Even the cargo which was thought impossible to consolidate, bulk or heavy, the only limits are internal dimensions and capacity of the shipping container. The number of shipping containers used globally is increasing dynamically and 20’ and 40’ ISO containers are the most common constructions. Standardization gives great advantage that shipping containers can be handled in every seaport but growing capacity of container ships makes loading time the most crucial aspect at the port terminal. High performance of gantry cranes and vehicles for internal transport reduces staff needed to operate such terminals. Every transshipment operations are controlled and supervised with the automatic Terminal Operational System. As a result, standardized procedures for container handling and automation and mass processes prevent individual treatment of individual shipments. Shipping containers are introduced into the system on the basis of the declaration of the shipper. In addition to the commercial information required external parameters of the container and its gross weight. In the case of universal containers are not uncommon any recommendations dunnage. Avoiding additional procedures reloading components guarantees fast service time and standard price for the service. In practice, therefore, there is a very limited possibility to check the information on the label of the container and the assessment of its current condition. Without calling the customs services there is no legal possibility of opening a container whose contents dubious from the point of view of the carrier or shipper. Containers that have not undergone proper verification during transshipment at the terminal can cause serious transport accidents. These events led to the loss of part of the containers, and even serious damage to the means of transport. Even one bad shaped container in which significantly exceeded permissible total or local load result in domino effect, leading to sinking of the entire ship. Frequently errors in stowage or anchoring cargo in the container can cause serious road accidents. The following analysis will focus on the consequences of transporting special container loads which are heavy cargo loads. These loads of high unit weight exceeding 5 tones, usually in the form of steel coils or machine parts. Such cargoes are often transported in standardized shipping containers, despite the fact that there is a possibility of selection of specialized containers having the appropriate structures for mounting this type of cargo. The use of universal containers is possible only provided the proper distribution of force exerted by the heavy cargo onto the floor of the container and its proper mounting. Strength calculations in this analysis focus on different construction of ISO shipping containers floor, including gooseneck tunnel. Shipping container floor construction Shipping containers specifications are dictated by the International Organization of Standards (ISO) and are subject to the control of the approved classification society. The load exerted by the stowed and fixed payload inside the container is transferred to the floor and frame structure through angular posts and the longitudinal and transverse beams. The standard floor of a container is stiffened by transverse steel beams equally spaced along the length of the container. The floor inside is covered with steel sheet and / or fiberboard with a thickness of 28 mm. 40 and 45 feet containers include gooseneck, which is a recess in the bottom of the container floor to secure of the container in the tractor unit. As a result, container loaded on a semi-trailer is lower by approx. 12 cm and can easily overcome obstacles like bridges. In accordance with standards so structured floor subject to static and / or dynamic tests, with uniform load no part of the base structure should extend more than 6 mm below the bottom plane of the bottom corner fittings. Fig. 1. Location and dimensions of gooseneck tunnel in accordance with the requirements of PRS [1] Fig. 2. Distribution of the load transfer areas in gooseneck tunnel (where the areas are not continuous) [1] Each load transfer area in the gooseneck tunnel (see Fig.2) consists of two parts - the upper A and lower B - forming a common the load transfer area. Sum of the areas (A and B) should not be less than 1250 mm2. The basic instrument establishing the principles of safe operation of containers is the International Convention for Safe Containers (CSC) from 1972. It requires the owners of the containers to maintain them in a safe condition. This obligation is implemented through technical inspections carried out in accordance with a specific timetable. There are two types of inspection: • Periodic - the first inspection of a maximum of 5 years from the date of manufacture and the next within a period not exceeding 30 months since the previous inspection. • Constant - within the approved program of continuous surveillance ACEP carried on not less than 30 months. The choice of the type of inspection is dependent on the owner or lessee of the container. Finite element modeling of the shipping container The work focuses on strength calculations of 40 feet shipping containers floor under heavy load cargo. The analysis is to indicate the dangers of heavy load stowed in the gooseneck area. There were compared three variants of floor structure: Variant A – heavy load outside the gooseneck area – standard containers floor. Fiberboard set on steel beams with the cross-section dimensions of the channel section 45x118x4.5 mm (Fig. 3) Variant B – heavy load in the gooseneck area without any stiffeners (Fig. 4) Variant C – heavy load in the gooseneck area with stiffeners with the cross-section of channel sections and dimensions 26x100x4.5 mm according to the manufacturer's instructions structural Singamas Container Holdings Ltd. [2] (Fig. 5) Fig. 3. Var. A - standard containers floor - bottom view Fig. 4. Var. B - floor in the gooseneck area - bottom view Fig. 5. Var. C - floor in the gooseneck area with stiffeners - bottom view Fig. 6. Finite element model of the container Simplified finite element model of the container (Fig. 6) has been executed in the program Abaqus / CAE v 6.11[3]. The design was based on the design drawings of several manufacturers. To speed up the computation whole container was modeled with the plate elements S4R - a 4-node doubly curved thin or thick shell, reduced integration, hourglass control, finite membrane strains [3]. Comparison of 3-d elements with shell elements of finite element containers models show similar results [4] therefor only shell elements were used in this analysis. Doors and roof of container have not been taken into account in the model since they do not have a strong effect on the results for this type of load. The material used for the calculations is characterized by parameters: Young’s modulus – E = 210000 Mpa, Poisson's ratio – ν = 0.3, yield Y = 400 MPa. For the analysis a steel coil with a weight of 2.64 tons and dimensions B = 2200, and φ = 1.5 m was assumed as a heavy load. The calculations are performed for the load case acceleration equal to 2G. The role is perched in the cradle which is characterized by a continuous pressure on the rectangular area of the floor with dimensions b = 2200 mm L = 800 mm. In the FEM model pressure with a value of p = 0.03 MPa was distributed in the area A = 1.76 m2 (Fig. 7 & Fig. 8) which gives effective load weight Q = 5.384 T. In the calculations heavy load is located 1030 [mm] from the edge of the container. Fig. 7. Pressure in the gooseneck area Fig. 8. Pressure in the area of standard floor Analysis results Table 1. Finite element method results Von Misses stress Maximum vertical translations Maximum vertical translation of the lowest point of the gooseneck tunnel Translation below the bottom plane of the bottom corner fittings (negative values are above the plane) Variant A 121,5 [MPa] 4,7 [mm] 4,7 [mm] Variant B 417,4 [MPa] 79,7 [mm] 27,1 [mm] Variant C 406,4 [MPa] 22,75 [mm] 16,9 [mm] -13,8 [mm] 8,64 [mm] -1.6[mm] Table 1 presents the results of calculation for the three variants of load of the floor structure. The results show more than four times greater Mises equivalent stresses in the case of loading gooseneck area. Differences of the maximum stresses for variants B and C are within 3%, however, varies their area. The analysis of variant C shows that stiffening gooseneck significantly reduces the area of stress exceeding the yield strength. Fig. 9. Von Misses stress in the Var. A Fig. 10. Von Misses stress in the Var. B Fig. 11. Von Misses stress in the Var. C Analysis shows that the largest maximum displacements occur in variant B, up to 79.7 mm. In practice, this means the deflection of the floor which causes maximum displacement of the lowermost point of the gooseneck tunnel will be 27.1 mm, which gives exceeded the allowable limit deformation of the floor of 9mm. Again you can see that in variant C achieved far better results that fall within the limits of the rules. Fig. 12. Vertical displacements in the Var. A Fig. 13. Vertical displacements in the var. B Fig. 14. Vertical displacements in the var. C Summary This paper presents results of strength analysis of shipping containers floor under heavy load cargo. Finite element model of the 40 feet standardized container was developed following container specifications. Different container floor constructions were considered. Based on the analyses, the following conclusions are drawn: - - - Heavy load cargo can be safely transported in the standardized ISO shipping containers with standard floor provided the proper stowage of the cargo. Transport of heavy cargo load in the area of gooseneck tunnel, for the constructions without stiffeners should not be allowable. Displacements of the bottom plane of the tunnel exceed values allowable by the rules. Shipping containers with the floor construction of the gooseneck tunnel that includes stiffeners fulfill the displacement rules but stresses in the construction exceed safety standards. Older containers should not be used in transport of heavy cargo loads since it is hard to verify its technical condition especially when we take in account degradation of steels during the service. Balyts’kyi and Chmiel [5], and Balyts’kyi, Chmiel and Trojanowski [6] show that in similar conditions hull steel (that is similar to steel utilized in production of shipping containers) that impact toughness and low-cycle fatigue resistance decrease with time. References [1] Polski Rejestr Statków, Rules for the Construction of Containers, Gdańsk, 2014. [2] Singamas Container Holdings Limited, Kukdong MES CO., LTD, information on http://www.singamas.com. [3] Abaqus Analysis User's Guide (version 6.11-2). Providence (RI, USA): Simulia; 2011. [4] K. Giriunas, H. Sezen, R.B. Dupaix, Evaluation, modeling, and analysis of shipping container building structures, Eng. Structures 43, (2012) 48-57. [5] O.I. Balyts’kyi, J. Chmiel, Resistance of plate shipbuilding steels to cavitation-erosion and fatigue fracture, Materials Science, Vol. 50, No. 5 (2015) 736-739. [6] O.I. Balyts’kyi, J. Chmiel, J. Trojanowski, Degradation of steels in the hulls of river ships, Materials Science, Vol. 43, No. 3 (2007) 434-438. View publication stats