Impact and Drop Testing

Impact events occur in a wide variety of circumstances across many industries including construction, transport and offshore. Uncontrolled impact and blast loading can have serious safety consequences, sometimes with devastating effect. We can see the tragic results of impact on the railways in the form of accidents such as those at Ladbroke Grove and Potters Bar. Less high profile, but nonetheless significant, examples include lifting equipment failures and workplace transport accidents. It is important to understand the physical characteristics of impact and its consequences to ensure a safe environment for workers and those affected by work activities.

The Health and Safety Laboratory (HSL) has a long history of providing high quality engineering research, technical support and advice in the field of impact. HSL's 550 acre site near Buxton, Derbyshire provides a unique capability for large scale experiments and includes the largest gravity impact track in Europe. Our wide range of expertise in engineering, materials science, computer modelling and specialist photography has been brought to bear on a number of major accident investigations involving impact. Our research work in this area is equally diverse in nature and has been used in the development of both national and international safety standards.

We are able to undertake a wide range of full-scale and sub-system impact testing to meet customer needs. We are committed to forging mutually beneficial relationships with our customers and to providing a quality service at an affordable price.

Facilities and Expertise
HSL has a comprehensive range of facilities and expertise that can be assembled rapidly to provide a multi-disciplinary response to meet our client needs. All our test facilities can be fully instrumented as appropriate with multi-channel digital data logging, optical tracking, video and stills photographic, high speed digital camera and thermal imaging systems to record experimental outputs.

Impact Test Tracks
These facilities allow high energy impact tests to be conducted on large engineering components and structures with the measurement of forces, displacements and accelerations. The test rigs extend over two acres and take advantage of the topography of HSL's Buxton site to generate the impact energy.

• Main track: 265 metres of four-rail track allowing two opposing trucks to run freely down opposite sides of a valley.
• Automated truck release at selected positions.
• Truck masses and speeds allow specimens to be subjected to impact forces in excess of 3MN (300 tonf) at speeds up to 27ms^-1 (60 mph).
• Maximum usable impact energy is 1.8MJ.
• Multi-channel digital data logging, optical tracking and high speed digital camera systems for recording output from various force, acceleration and displacement transducers.
• Adjacent laboratory which can be protected from fire and impact damage by the use of water screens and concrete barriers.
• Separate railway impact track.

This facility is available to public and private sector customers from the UK and overseas and is complemented by the analytical and interpretative skills of HSL's experienced scientific and technical staff.

  Further information

25 Metre Test Tower
This facility is a purpose-built tower designed to accommodate drop testing and other structural experiments. Either solid or wire rope guides can be installed readily to the tower sections to enable a controlled, guided drop of the sample to take place.

Features
• Winching system capable of hoisting masses up to 1000kg
• Substantial concrete foundations and thick steel impact pad
• Impact area can accommodate samples up to 2 metres square
• Impact velocities in excess of 20ms^-1
• Rocket propulsion can be accommodated if higher impact velocities are required
• Multi-channel digital data logging, optical tracking, high speed digital camera systems and thermal emission recording equipment for recording output
• Recording equipment housed in protected accommodation adjacent to the impact area.

Drop Test Facility
This facility is used to measure the response of engineering components to impulse loading including reactive forces, acceleration and dynamic displacement.

Features
• Substantial vertical 5 metre steel tower with a 10 tonne lifting capacity hoist
• Sophisticated control and release system permitting a variety of drop masses to be released at any point up the tower
• Drop mass can be varied up to a maximum of 10,000kg
• Available drop height of 4m, controllable with an accuracy of +1mm
• Impact velocities up to 13ms^-1

High Speed Gas Gun
This facility is used to measure the response of engineering components to high velocity impulse loadings.

Features
• 3 metre barrel length
• Short closed breech section used to install the projectile and propulsion charge; and a short one metre length of protractor. This latter structure is used to vent the products of combustion sideways thus reducing any obscuring smoke from the impact region
• Capable of projecting a missile with a mass up to 25kg at any speed up to 300ms^-1
• Can be used in either horizontal or vertical mode depending on requirements
• High speed digital video for monitoring and recording projectile speed and the effects of impact

Expertise
• Engineering and materials science
• Structural integrity
• Engineering critical assessment - fracture mechanics, fatigue studies
• Finite Element Analysis and modelling
• Development of instrumentation and logging equipment
• Fluid-structure-interaction modelling
• Specialist video, stills and high speed photography
• Specialist design and workshop skills
• Experienced project management for large scale field trials

Applications
Examples of impact related research, consultancy and investigative work carried out by HSL include:
• Crashworthiness of railway vehicles/components
• Assessing the performance of locomotive override protectors
• Impact resistance of fuel tanks
• Dynamic testing of chains, hooks and wire ropes
• Assessing hydraulic lift arrestor systems
• Impact characteristics of large reinforced concrete beams
• Assessing the performance of energy absorbers for offshore use
• Dynamic performance of safety harnesses
• Measuring the toughness of large notched rectangular hollow section
steel specimens
• Effects of dynamic loading on aluminium honeycomb panels used in nuclear reactor charge floors
• Assessing the pressure surge from the roll-over of road tankers
• Assessing the performance of scaffold boards and cast iron structural support columns under a variety of impact conditions
• Assessing the performance of industrial safety nets

Further Details
Contact our Business Development Unit by telephone (+44) 01298 218218, fax (+44) 01298 218822 or email hslinfo@hsl.gov.uk.

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