Head Expanders / Thermal Barriers

Head expanders consist of a large platform that is bolted to the shaker’s load table. They are part of many vibration test systems, and by increasing the effective mounting surface to accommodate larger or numerous payloads, a head expander increases the capability of existing shaker systems.

To enable the use of climatic chambers during environmental testing, a thermal barrier protects the shaker from high and low temperatures. Depending on your testing needs, thermal barriers can be used with or without head expanders.

All our medium- and high-force shakers (with armature diameters from 335 to 760 mm) can be fitted with a variety of head expanders and thermal barriers.

USE SCENARIOS

• Increasing the effective mounting surface of a shaker’s armature
• Accommodating larger, bulkier payloads
• Increasing the quantity of articles that can be tested at one time, reducing total testing times
• Providing increased flexibility in fixture design

CHARACTERISTICS OF HEAD EXPANDERS

Designed using finite element analysis (FEA) technology, LDS® Head Expanders are cast from a high-strength, aerospace-grade magnesium alloy with excellent damping properties to minimize force dispersion. They have a usable frequency range from DC – 2000 Hz. To prevent corrosion, non-machined parts are painted, and machine parts are coated with lubricant.

We offer two types of head expander as standard products: guided and unguided.

• Guided head expanders enable you to test payloads with masses greater than those the shaker can support. Available for LDS® V875, V875LS, V8, V9x shakers (whether trunnion- or combo-mounted) they are 1200 mm2 in size and have a support capability up to 1200 kg.
• Unguided head expanders allow you to test payloads whose dimensions exceed those of the shaker’s armature work surface. As they are intended to accommodate larger – not heavier – articles, unguided head expanders do not provide additional load support. Unguided head expanders for the V850, V875, V875LS, V8 and V9x come in four sizes: 610, 762, 1000 and 1220 mm2 – for model V830-335, a 610 mm2 expander is available. Head expanders are also available for the larger water-cooled systems, including the 289 kN V994 shaker system.

For immediate testing, all head expanders are supplied complete with fasteners and fitting tools, including keyed payload attachment inserts in both grid and armature patterns, as well as armature screws, dedicated wrench key and torque wrench, and lifting eye-bolt.

CHARACTERISTICS OF THERMAL BARRIERS

By reducing the heat conductivity between payload and shaker (or slip table, if one is used), thermal barriers enable vibration testing systems to operate with climactic chambers for environmental tests. We offer thermal barriers to match all sizes of head expander in the LDS range; other insert patterns can be supplied to special order.

The thermal barrier has clearance holes corresponding to the expander’s insert pattern and M6 helicoil inserts along the edges for the clamping strips. All thermal barriers are supplied with lifting eyebolts, clamping strips, corner clamping strips, and attachment screws.