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Manufacture of shells for field guns with improved design and performance

Primary Information

Domain

Manufacturing

Project No.

6596

Sanction and Project Initiation

Sanction No: F. No. 3-18/2015-T.S.- I(Vol. III )

Sanction Date: 24/04/2017

Project Initiation date: 01/.8/2017

Project Duration: 24

Partner Ministry/Agency/Industry

Ministry of Defence/Ordnance Factory Board

 

Role of partner: Providing necessary facilities and resources for prototyping and testing of the shells with new designs and improved performance. i. Trial manufacturing of the new shells a. Prototyping and testing b. Manufacturing of sample of new shells ii. Field testing at site a. Testing and performance data collection b. Analysis of the performance data c. Final testing with accepted process plan and performance.

 

Support from partner: i) Operational Support a) Providing necessary data for analysis of present shell design and shell performance (Ballistics) assessment b) Manufacturing prototypes of required units c) Utilizing the test facilities ii) Financial Support: 50 % of the total project cost.

Principal Investigator

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Prof. Pradip Kumar Ray
Indian Institute of Technology Kharagpur

Host Institute

Co-PIs

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Dr P L Narasimhan
Indian Institute of Technology Kharagpur

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Dr. Vikranth Racherla
Indian Institute of Technology Kharagpur

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Dr. Debalay Chakrabarti
Indian Institute of Technology Kharagpur

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Prof. Biswajit Mahanty
Indian Institue of Technology Kharagpur

 

Scope and Objectives

The following objectives with respect to design and manufacturing of the shells have been set: (i) To evaluate the existing design and manufacturing system currently in use from a number of perspectives, like materials property, design specifications, process capability, quality assurance, product and production cost, throughput time, etc. (ii) To develop an improved/new design of the shells and their manufacturing system, and (iii) To develop an integrated design and manufacturing process following the concurrent or simultaneous engineering (C/SE) approach. The scope of the research lies in the fulfillment of above-mentioned objectives in respect of 130-mm and similar types of shells.

Deliverables

The project work involves assessment of the existing design and manufacturing system of the shells, and development of the improved design and manufacturing system. The following outcomes and deliverables of the project meeting the project objectives are worth mentioning: (a) Reports on (i) cracking and failure study of shells, (ii) microstructure, hardness and residual stress distribution insides shells, and (iii) plant processing parameters, (b) Assessment of the existing design of the shells in terms of their specifications, quality and performance with selection of proper metallurgical characteristics, (c) Assessment of the existing manufacturing systems of the shells in terms of their production cost, and quality control and assurance, (d) Development of improved design of the shells, (e) Process planning for the shells, (f) A calibrated and validated material model for shell steel, (g) Monitoring and control mechanism for performance assurance of manufacturing processes, and (h) Development of C/SE Framework for shell manufacturing. In particular, the project deliverables are as follows: (i) For the IIT Team: (a) Design of the shell, and (b) Detailed process plan. (ii) For Ordnance Factory, Ambajhari : (a) Manufacture of 100 shells of improved design (test samples), and (b) Conduct of field trials for accuracy and consistency

 

Scientific Output

The Scientific studies and outcomes may be classified under the following categories: i) Effect of Process Settings ii) Effect of Errors on Shell Eccentricity iii) Study of Ballistic Behaviour iv) Important Sample Observations in Processes Process: Forging Process: Nosing Process: Machining v) Effect of Wall Thickness Variation (WTV) on radial force vi) Study of defects of shells under trial vii) Estimation of average WTV through defect analysis viii) Dynamic Balancing Study ix) Dynamic simulation and Finite element analysis x) Internal and External Ballistic behavior evaluation, including Balloting xi) Evaluation of Aerodynamic efficiency and flight stability xii) Materials property studies with respect to fragmentation at terminal ballistic stage Effect of Process Settings The run-out due to the effect of tolerances Errors observed compared to norms and standards. Effect of Errors on Shell Eccentricity There are various kinds of errors that may be occurring at each of the machining stages/processes. The total error in the output from last stage as obtained at the last stage of machining process last terminating (finished turning) process represents cumulative effect of individual errors occurring at all the previous processes.These errors lead to eccentricity in the shell. Effect of Eccentricity on Internal Ballistic Behaviour For the given shell, its ballistic behaviour in terms of maximum speed (rpm) achieved, travel time, and the radial force at the exit point has been studied. While analyzing the ballistic behavior of the shell, three eccentricity values of 0.25 mm, 0.5 mm and 1 mm are considered. It is observed that: The radial force on the barrel is mainly due to the eccentricity combined with rotational speed of the shell. The maximum angular speed is formed as about 13,221 rpm with the corresponding radial force of about 64kN. Important Sample Observations in Processes For production of 130 mm shell as per its standards/specifications, three processes, viz. forging, nosing, and machining are most critical. In order to assess their performance, viz-a-viz, conformance to quality standards, sample observations are made and analyzed. Effect of Wall Thickness Variation (WTV) on radial force The WTV of a shell is inspected at seven specific locations along its axis. For analysis purpose, the WTV is inspected at those specified locations as being practiced. The WTV of a shell may result in its unacceptable performance. Directly it leads to mass imbalance. Since the WTV values may be different along the axis of the shell, there may be multiple mass imbalances. The polar orientation of the mass imbalance may also vary as a consequence. Estimation of average WTV through defect analysis The mass imbalance induced is computed for all seven zones in a shell with the consideration of average WTV of the shell. From comparative Study, the values of AWTV for each of the 180 shells considered for study is less than the specified value of 2.0 mm; however, a shell may have various engraving or stenciling defects. If the value of AWTV is less than 0.46 mm (specific eccentricity of 155 micron), the defects can be of stenciling only and hence, may be accepted. Dynamic Balancing Study To calculate the dynamic unbalance, a shell is assumed to be a rigid rotor (supported at two rollers) with two balancing planes. There are seven mass imbalances along its axis. These masses exert radial forces that may be resolved at two balance planes (where corrections may be applied).

 

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Results and outcome till date

A detailed workplan for the inspection and testing of the prototypes of shell manufactured as per the modified design is being developed with participation of both IIT Kharagpur team and OFAJ team. The workplan is made as per the NATO Standardized Agreement (STANAG).

 

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Societal benefit and impact anticipated

The shells for field guns, manufacturing by Ordnance Factories as per its design supplied by foreign countries, have a number of deficiencies in their manufacturing system affecting performance of the shells in field testing. Considering strategic importance of defense preparedness from national perspective, technological up-gradation in design and manufacturing is essential. Innovative methods in both design and manufacturing system are necessary to improve the ballistic behavior of the shells. Development of indigenous methods is essential in this context to lessen the dependence on foreign suppliers. This project aims to develop an improved design and manufacturing processes (design details and process plans as deliverables) for the shells for field guns of defence services ensuring optimal manufacturing performance and best-possible ballistic behavior based on design, manufacturing, metallurgical and materials research as planned for the existing 130 mm and similar types of shells with active support of Ordnance Factory Board. In a country like India, where the design of defence-related products in majority of the cases is imported, the manufacturing system to be engaged for producing such products must be made world-class where the primary condition to be satisfied is to verify if the design is compatible with the manufacturing and to what extent the design and manufacturing can be integrated in overall product development process. The methodology to be used to address the research objectives will establish these issues for shell production in Ordnance Factories of the defence services. In order to achieve the objectives of the project work, the Ordnance Factory, as a partner and a client to this research effort and outcome, has the potential and capability to respond to various kinds of changes and demands, as needed for carrying out the steps in the methodology vis-a-vis product development process for the shell. While implementing and adopting the proposed research methodology, a collaborative and multidisciplinary approach is to be used. The proposed research work is a product development initiative leading to the development of indigenous shells with optimal manufacturing performance, production sustainability and assurance of ballistic behaviour. Literature on shell design and manufacturing shows that different types of shells (early shells, shrapnel shells, armour piercing shell, anti-tank explosive shells, etc.) with various manufacturing methods and materials have been used since their inception in World War-I. Hence, there exists enormous possibility to improve design and manufacturing system for the shells. Materials for the shells can be of different types, like low, medium and high carbon steels, alloy steels, high fragmentation steels, etc. Among the currently used processes like billet preparation, forging, shot blasting, contour turning, nosing, machining operations, etc., attempt will be made to apply CNC technology to assure compliance with overall cavity length, base thickness, eccentricity, wall thickness and other quality characteristics of the shells. All the above mentioned aspects, when considered and implemented, will have a significant impact on societal benefit in national level in terms of self reliance in Defence Armament Design and adoption of State of the art materials, methods and technology.

Next steps

Activity-4 Trial Manufacturing, Field Study, and Standardization of Design and Manufacturing Systems (Timeline: August 1, 2018 to July 31, 2019) At OFAJ Trial manufacturing of the new shells (Prototyping and testing, Manufacturing of sample of new shells) Field testing at Chandipur site (Testing and performance data collection, Analysis of the performance data, Final testing with accepted process plan and performance) At IIT Kharagpur Final recommendation (Design blueprint, Process plan, and Preparation of the final report) At OFB Kolkata Meeting and presentation of final design Activity-5 Development of the Process Plan (Timeline February 1,2019 to April 30, 2019) At OFAJ Interaction meeting with project team regarding detailed process plan At IIT Kharagpur Determination of detailed specifications including selection of the materials, processes, machine tools, holding devices, control mechanism including inspection and quality control, and setups Finalization of the process plan At OFB Kolkata Interaction meeting on finalization of process plan for the new Design

Publications and reports

Three papers are under preparation at advanced stage: 1. Artillery Shell design in India :Scope and Status 2. Study of tolerances in shell manufacturing 3. Shell Design considerations and practices To be communicated to international journals of repute for publication

Patents

Nil

Scholars and Project Staff

Two Junior Research Fellows (Mr Suvradip Samaddar and Mr.Debasis Panda) Tenure : May 2018- July 2019/Till completion of the project.

Challenges faced

Not applicable at this stage (currently, the project is at prototyping stage, and on completion of testing at the work site, the product with new design will be implemented)

Other information

Committed Expenditure for Manufacturing and Equipment Purchase: As per the work plan of the project, budgeted amount of Rs 96,00,000 (Rs 30,00,000 for equipment and Rs 66,00,000 for Dies/Tooling/Precision Gauges) along with required software for data analysis will be utilized by partner organization (Ordnance Factory Board, Ministry of Defence) for making a number of prototypes of shells as per the new designs and subsequent field testing during the third phase as planned. Prototyping during the current third or penultimate stage of the project has already been initiated for which the above-mentioned activities are being carried out and respective amount of Rs 66,00,000 will be charged by OFAJ (Partner Industry) tentatively by December, 2018. Making of workstation with facilities, as stated above (in serial no 10) is in progress (purchase order being placed) and an amount of Rs30,00,000 is committed to it.

Financial Information

  • Total sanction: Rs. 19000000

  • Amount received: Rs. 11874975

  • Amount utilised for Equipment: Rs.199800

  • Amount utilised for Manpower: Rs. 400000

  • Amount utilised for Consumables: Rs. 0

  • Amount utilised for Contingency: Rs. 85481

  • Amount utilised for Travel: Rs. 296429

  • Amount utilised for Other Expenses: 118743

  • Amount utilised for Overheads: Rs. 2374995

Equipment and facilities

 

Work station and allied software tools (ANSYS Workbench, ABAQUS CAE, MATLAB Aerospace Module, FORGENxT) with the following computational requirements: a. Stress analysis of shellto simulate the internal ballistic phenomenon b. Flow simulation of the external ballistics c. Simulation of the trajectory of the shell after firing d. Study and simulation of material flow during nosing operation