Marine Structures and Survivability

Effective Test and Evaluation (T&E) is critical to ensure modern high performing and complex vessel designs are operationally reliable, efficient and safe in hostile and challenging environments.

It is imperative that all equipment and systems within an operational warship not only have proven reliability but that any installation is also fit for purpose and does not compromise other systems or the safety of the crew. QinetiQ’s specialist dynamic shock test service provides the most representative method of equipment and system shock qualification for onboard installation.

Our shore-based shock machines replicate the structural response of a ship or submarine to the initial dynamic shock loading resulting from an underwater explosion. This ensures equipment is tested in the most representative manner and, by identifying any potential performance shortcomings, enables design and system specifications to be modified to minimise operational risks.

Shock Test Capabilities

• Specialist UK facility
• Deck shock machine
• Two tonne shock machine
• Expert impartial advice
• Effective and representative
• Tests meet NATO and national design requirements

Tests satisfy, MAP01-470, BR8470 & BR3021, DefStan 08-123 Data Sheet 27 & 28, NATO Stanag 4549, other Design Shock Response Spectrums (DSRS)

Deck shock machine – simulates the shock experienced by equipment on decks and bulkheads that are remote from a ship’s hull.

Payload up to 900kg and acceleration up to 900ms-2, depending on payload.

Two-tonne shock machine – simulates the shock experienced by equipment on the hull and structures close to the hull of ships and submarines:

Table size 2300mm x 1100mm and acceleration 2000ms-2 up to 2000kg payload

QinetiQ delivers expert structural analysis using a blend of appropriate engineering calculations through to leading-edge Finite Element (FE) modelling. Our service covers non-linear static and dynamic analysis, including collision and other applications. These include specialist areas such as fracture and fatigue, design optimisation, fluid structure interaction and localised stress analysis to support safety assessments.

Structural Analysis
Linear static analysis is used to develop an understanding of a structure’s behaviour before more complex analyses and in validation exercises against simpler analytic or numerical solutions are undertaken. It is often used in detailed stress analysis and, in some cases, can provide sufficient results without the need for more expensive procedures. Many processes are, however, non-linear by nature so will require more complex analysis.

By way of example, the collapse of a submarine hull under hydrostatic pressure involves geometric non-linearity, elasto-plastic material behaviour and loss of stability and is sensitive to shape imperfections, fabrication residual stresses and other variables. QinetiQ has extensive experience in non-linear collapse modelling - including any need to address fabrication issues - that has been validated against a substantial body of experimental test data. Such advanced techniques have also been applied to many other areas of submarine design and in-service issues.

Expert Finite Element Analysis
Finite Element (FE) analysis has become ubiquitous in engineering and science. The increase in computing power and capacity and the enhanced capabilities of the latest FE software products enables increasingly sophisticated analyses to be performed. As the scope for alternative and evermore complex analyses widens, QinetiQ’s stakeholders and customers benefit from the reassurance and added value provided by our specialist team and world class expertise in FE analysis.

Dynamic Analysis
The options and scope for dynamic analysis continues to grow. This may take the form of additional inertia forces being applied to a relatively simple extension of linear static procedure. Alternatively, it may entail structural dynamics at relatively low frequencies or explosive transient events involving very high frequency responses. QinetiQ has a wealth of experience in all of these areas and has extensive experimental test data to support and inform our analyses for even the most complex application. The grounding of submarines is a good example. Here, the analysis will involve structural dynamics, contact, fluid-structure interaction, non-linear material behaviour and structural response under hydrostatic pressure.

QinetiQ provides customers with expert structural integrity analysis and assessment. Our services are delivered in accordance with national and international standards that support defect acceptance and concession, safety and safe to go to sea assessments.

Structural Integrity
Structural integrity is a function of a structure or component’s ability to withstand in-service loading, resisting failure by fracture, deformation, buckling and collapse, or fatigue. QinetiQ has extensive experience in assessing complex loading and both static and dynamic loads as well as thermal and shock stresses, and we apply a wide range of skills to provide insightful and informed structural integrity analysis. Our service covers:

• Stress analysis
• Plastic collapse
• Buckling/Instability assessment
• Fatigue analysis
• Fracture analysis
• Crack propagation
• Corrosion fatigue
• Stress corrosion cracking
• Leak before break
• Weld analysis
• Pitting and wall thinning

Relevant standards include BS 7910, BS 7608, BS EN 1993-1-9, and PD5500.

Critical Inspections, Evaluation and Analysis
QinetiQ has a track record of developing and applying bespoke non-destructive evaluation (NDE) procedures that accurately determine the size of flaws and fulfil the requirements of an engineering critical assessment (ECA).

Non-destructive Evaluation
QinetiQ delivers expert advice and consultancy services in all areas of NDE. These include guidance on advanced ultrasonic techniques and inspection methods for marine composites as well as development of ‘fitness-for-purpose’ fracture mechanics using weld defect acceptance criteria, through-life methodologies, defect and crack growth monitoring and critical NDE. We also provide guidance on weld repair options, technical training in advanced ultrasonic and in the inspection of complex weld geometries.

Through-life Strategies, Repair Advice and Guidance
QinetiQ provides guidance on suitable in-service inspection regimes, NDE techniques and procedures for both metallic and composites structures. Our experience of developing fitness-for-purpose weld defect acceptance criteria has included one of the most complex engineering constructions in the world as well as determining critical flaw sizes under ECA assessments. Training, demonstrations, auditing of external NDE reports and peer review of design calculations (FE and hand-calculations) are all provided to customers.

Building on decades of testing experience and a deep understanding of survivability, QinetiQ helps users understand anticipated platform performance during hostilities or in challenging environments. This includes an assessment of consequences to the platform and all of its systems from an attack as well as recoverability - including the evacuation of the crew, if required.

Harnessing our market-leading Survive® modelling and assessment software, our survivability experts quantify the effects caused by damage sustained on a ship or submarine. This allows different protective strategies to be compared so that the most effective option can be selected. It also enables simple manipulation of designs or in-service platforms to assess the impact on vulnerability.

Thousands of potential attacks or damage scenarios can be analysed within minutes to provide prompt appraisal of designs based on engineering expertise and real world experience.

Vulnerability Analysis
QinetiQ provides computational predictions and modelling to determine the vulnerability of ships and submarines for blast, fragmentation, shock, whipping, fire and flooding damage. By assessing the damage inflicted to equipment in different scenarios, we will establish the vulnerability of the platform’s systems and, ultimately, the resilience of its primary capabilities - such as the ability to fight, move and float.

Lethality Analysis
QinetiQ performs lethality analyses for different weapons - from missiles, bombs, torpedoes and mines to improvised explosive devices (IEDs) and swarming autonomous vehicle attacks. QinetiQ can investigate a weapon design to determine its lethality. The impact of a weapon design can be investigated by changing aspects of the weapon, such as the warhead explosive content, velocity, fragmentation pattern and fuzing logic.

Recoverability Analysis
Using computational modelling, QinetiQ will investigate and assess alternative recoverability strategies for different forms of system, equipment or platform damage. Such assessments typically include:

• Firefighting
• Shoring of structure and pumping of flood water
• First aid treatment of casualties
• Repair of damaged equipment and restoration of key systems
• Crew ability level and location within the vessel

In addition, we will carry out evacuation analysis to determine evacuation times from a damaged platform.

Further information on QinetiQ’s Survive® software tool can be found here: Survive®